Does crimping help or hurt accuracy?

[NamibHunter]

Have been struggling with high ES (35 fps or more) in my target load, even though SD is usually below 10 (typically 6-8 fps). Always 2-3 wild shots that mess up the ES.

Tried higher neck tension and the gun seems to like that more. Went to very high neck tension (5 thou), via a Whidden FL die with a full set of sizing buttons of different size, and during the seating process the (narrow) resized case neck cuts the pressure ring clean off the bullet. Bad!

Have had good success before crimping hunting bullets like the Barnes TTSX. So tried to crimp a Berger Hybrid batch to increase neck tension.... Of course, no cannelure on a Berger target bullet....

Unloaded 4 of the crimped rounds.... they all had varying degrees of damage (deep annular indentation in the bullet bearing surface). So clearly i damaged the Berger Hybrid projectiles in the crimping process.... Some had pretty ugly deep indentations and others had very little... inconsistent, so obviously this not going to work very well at distance, as BC will shift quite a bit i guess, and speed could be affected too. SD was 8.7 (pretty good) but ES was 36 fps, which is too high (even after deleting the cold bore shot).

BTW: The box of ammo shot well (0.4-0.6” groups) at 100 yards, which is a little surprising...

Does the bullet “slug” up when it accelerates at several thousand g’s down the barrel, and push the jacket outwards against the grooves, undoing some or most of the crimp indentation? Or at least making it more consistent?

Root cause: I think some cases might have been 1-2 thou shorter than others, and they get crimped very little. Hard to get them exactly the same length. The longer cases will have the most severe crimp - by quite a lot!

Measured the case length post firing and they vary by 5 thou, but that probably does not mean much.

I guess only bullets with a proper cannelure are suitable for crimping?

[.... and i guess crimping is most useful in a gas gun? BTW: Crimping did improve accuracy of my Barnes hunting load for a 30-06 bolt gun.]

 

[Dstoenner]

I use Lee Factory Crimp Die on my rounds and found they do not make accuracy worse but can help it a little by making a more uniform neck tension for the batch.

david

 

[RTH1800]

Might try a Redding taper crimp die but I suspect your problem is elsewhere. Old brass, powder charge etc?

 

[NamibHunter]

Thanks for the Redding taper crimp die suggestion, will look into it.

Rarely used crimping before on a target load, and this was only an experiment. Generally use an FL die with different bushings (Redding Type S), or the Whidden non-bushing die with different size expanders, or a bushing neck die. Can get ES to 30-34 fps range. Was hoping the crimp die can get it below 25, but no luck!

Any other way to get neck tension up without damaging the projectiles? How high is too high....

Would a solid copper target bullet like a Cutting Edge do better with crimping?

 

[NamibHunter]

I use Lee Factory Crimp Die on my rounds and found they do not make accuracy worse but can help it a little by making a more uniform neck tension for the batch.

david

@Dstoenner: What bullets do you crimp with the Lee die? If you pull the bullet, do you see any damage.

 

[Dstoenner]

@Dstoenner: What bullets do you crimp with the Lee die? If you pull the bullet, do you see any damage.

I don’t use the full crimp capability but i have pulled bullets and there is a faint ring at the crimp site. I think the lands would iron it all out. I use it on on 223,308,30-06,6br,6x47L and 17 Hornet

David

 

[Skeptic1]

i don't crimp unless loading 45acp or .223 to be run through a gas gun. I can't tell you what to do but...... stop crimping your precision loads.
You can add as many steps as you want and buy as many different seating dies as you want. At the end of the end of the day you'll not beat the Lee factory dies.
I use to be ashamed to say that but, I've lived a bit longer now.

 

[Nimothy]

I honestly think your problems are somewhere else besides a crimp or neck tension. What are you loading and with what components

 

[NamibHunter]

Lapua SRP brass 5x fired
MPA comp rifle in 6.5 CM
Berger Hybrid 140 gn
H4350
GM205M or CCI450
Loaded to book length (not optimized jump yet)
COAL of 2.80”
Brass is fully prepped and neck turned
Concentricity 1-3 thou range, average 1.5 thou of bullet runout
Loaded to 0.04 gn on FX120i

 

[Gustav7]

How many rounds you got down the tube?

I also use the Lee Factory Crimp on my good AR loads. I set it up so i can just barely see the faintest mark from the crimper...then I back it off just a touch. I will most likely not be using the factory crimp on my upcoming 6.5cm loads. I'll run a batch with 0.002 neck tension and see how those go.

 

[Milo 2.5]

Loaded to book length (not optimized jump yet)

Before you go all out with a crimp, or even neck tension variations, do you think it is possible finding the primo seat depth may iron out some discrepancies?

 

[Nimothy]

Lapua SRP brass 5x fired
MPA comp rifle in 6.5 CM
Berger Hybrid 140 gn
H4350
GM205M or CCI450
Loaded to book length (not optimized jump yet)
COAL of 2.80”
Brass is fully prepped and neck turned
Concentricity 1-3 thou range, average 1.5 thou of bullet runout
Loaded to 0.04 gn on FX120i

All of that looks about like what I do, but 1-3 thou on turned brass is concerning. What’s your charge weight and what speed are you running those 140’s at? I’ve found that when your not in a node, your numbers look like you’re shootings a sbr with cheap as it comes xm193 (that shit is really whacky when it comes to consistent velocity) also how far are you setting your shoulders back. What numbers do hornady factory eld ammo give you? And last but not least what crono?

 

[Bender830]

I see the argument against crimping as this: you want more pressure holding onto the bullet then I would want that pressure to be uniform. How can squeezing the brass into the bullet possibly be uniform if the brass itself isn't uniform? Thicker material here means its forced further in that where its thin over there. That seems like it would only exacerbate neck tension issues unless the necks were turned. And no one wants to turn necks that would then just squeeze them down into a bullet.

 

[NamibHunter]

How many rounds you got down the tube?

I also use the Lee Factory Crimp on my good AR loads. I set it up so i can just barely see the faintest mark from the crimper...then I back it off just a touch. I will most likely not be using the factory crimp on my upcoming 6.5cm loads. I'll run a batch with 0.002 neck tension and see how those go.

The MPA is a new, about 250 rounds so far, gun shoots like a champ, out to 300 yards. Even with Hornady 140 Match and Berger factory ammo, with groups around 0.4”.

Hand loads: Group size is on average 0.25” to 0.35” MOA, so very happy with the gun. Some vertical stringing issues at longer distances. Want to get ES down below 25 fps (so looking for a 30% improvement). SD is good enough, but usually 2-3 rounds that end up exceptionally slow or fast. Scrubbed out a minor carbon ring. Brass has all been trimmed shorter than trim length (1.905”) to keep it consistent as some came out if the blue Lapua box shorter than they should be...

Would my load development benefit from serializing the brass and checking if the same brass cause the problems and cull them? I put aside any loaded rounds that have concentricity (runout) worse than 3 thou and use those for fouling shots.

Have tried all of the following and it did not help: Bullet weight sorting, primer weight sorting, case weight sorting. Putting aside loaded rounds based on poor runout (Concentricity) but going to higher neck tension helped some.

I have the kit to measure seating force (K&M press) and can cull the loaded rounds that seat light or heavy. Will try that next.

I shoot slowly, have a temperature strip on the barrel, stop when barrel temp gets to 120, and cool it down to 100 deg F before restarting, and usually delete the cold bore shot (always 15-25 fps slower). Some rounds are in the chamber for 5 seconds, some for 2-3 minutes (so perhaps “cooking” the rounds?) as i tend to wait for the wind speed and direction to go back to normal. Is that the main cause of my problems??

 

[Gustav7]

I see the argument against crimping as this: you want more pressure holding onto the bullet then I would want that pressure to be uniform. How can squeezing the brass into the bullet possibly be uniform if the brass itself isn't uniform? Thicker material here means its forced further in that where its thin over there. That seems like it would only exacerbate neck tension issues unless the necks were turned. And no one wants to turn necks that would then just squeeze them down into a bullet.

I could see this with serious crimping, meaning a lot of force. I always thought of Lee Factory Crimping as additional help to keep excessive runout in check...provided the crimp is very light in force. I don't think it necessarily applies to someone turning necks etc.

As a hypothetical, lets say some standard attention (not BR retentiveness) precision loads average about 2-3thou of runout or so. I view a light lee crimp being able to bring the 4-5 thou variations down to the average of 2-3thou. So its sort of grabbing the outliers or poorly seated/sized/etc rounds and bringing them back into check, giving you more consistent and accurate loads overall.

I think the advantage something like a light Lee crimp gives you goes down with the more precise and better components you're utilizing. I'm sure theres also just random cases where a Lee crimp seems to help a specific rifle or load all the time, etc. Just my $0.02

 

[Gustav7]

The MPA is a new, about 250 rounds so far, gun shoots like a champ, out to 300 yards. Even with Hornady 140 Match and Berger factory ammo, with groups around 0.4”.

Hand loads: Group size is on average 0.25” to 0.35” MOA, so very happy with the gun. Some vertical stringing issues at longer distances. Want to get ES down below 25 fps (so looking for a 30% improvement). SD is good enough, but usually 2-3 rounds that end up exceptionally slow or fast. Scrubbed out a minor carbon ring. Brass has all been trimmed shorter than trim length (1.905”) to keep it consistent as some came out if the blue Lapua box shorter than they should be...

Would my load development benefit from serializing the brass and checking if the same brass cause the problems and cull them? I put aside any loaded rounds that have concentricity (runout) worse than 3 thou and use those for fouling shots.

Have tried all of the following and it did not help: Bullet weight sorting, primer weight sorting, case weight sorting. Putting aside loaded rounds based on poor runout (Concentricity) and going toigher neck tension helped some.

I have the kit to measure seating force (K&M press) and can cull the loaded rounds that seat light or heavy. Will try that next.

I shoot slowly, have a temperature strip on the barrel, stop when barrel temp gets to 120, and cool it down to 100 deg F before restarting, and usually delete the cold bore shot (always 15-25 fps slower). Some rounds are in the chamber for 5 seconds, some for 2-3 minutes (so perhaps “cooking” the rounds?) as i tend to wait for the wind speed and direction to go back to normal. Is that the main cause of my problems??

The only thing I can think of...and I'm not an expert so just honest opinion, is you might be on the edge of a node. I found a high node around NATO max pressure in my AR using 77gr TMK's, but the node seems tiny. I'd have 8/10 shots with great placement, then have 1-2 fliers, both physically on target and in the chrono. It drove me to forgo using TAC and pick up some XBR 8208 to try and find a better node above 2600fps. Just a thought.

Sounds like you're doing everything right

 

[Bender830]

I could see this with serious crimping, meaning a lot of force. I always thought of Lee Factory Crimping as additional help to keep excessive runout in check...provided the crimp is very light in force. I don't think it necessarily applies to someone turning necks etc.

As a hypothetical, lets say some standard attention (not BR retentiveness) precision loads average about 2-3thou of runout or so. I view a light lee crimp being able to bring the 4-5 thou variations down to the average of 2-3thou. So its sort of grabbing the outliers or poorly seated/sized/etc rounds and bringing them back into check, giving you more consistent and accurate loads overall.

I think the advantage something like a light Lee crimp gives you goes down with the more precise and better components you're utilizing. I'm sure theres also just random cases where a Lee crimp seems to help a specific rifle or load all the time, etc. Just my $0.02

How can crimping uneven brass possibly make the resultant force imparted on the bullet more even? And then even straighten it to boot?
If you have runout issues then you need to fix the cause, not squeeze on it.

 

[Gustav7]

How can crimping uneven brass possibly make the resultant force imparted on the bullet more even? And then even straighten it to boot?
If you have runout issues then you need to fix the cause, not squeeze on it.

Because the runout that uneven brass causes could be less than the runout thats currently on the round. If squeezing on uneven brass causes 0.003 of runout, but the round itself due to some error has 0.005 runout, then a lee crimp die could bring that runout down, making it more consistent across the board. It was hypothetical, and its very possible it could happen. Theres a lot of people who use lee crimp dies because they notice a difference. Not to mention the majority of people aren't turning their brass and some of them are still getting great results, myself included. I use a lee crimp on my AR, but not on my 6.5cm. I have yet to see where the crimp hurts me. But as always, ongoing testing is constant.

Im not advocating that a lee crimp will fix his issues, just speaking about how I envision a lee crimp working for some people.

 

[NamibHunter]

Before you go all out with a crimp, or even neck tension variations, do you think it is possible finding the primo seat depth may iron out some discrepancies?

Fair point. I was planning to do seating dept optimization after finding the best speed range (node) and usually get positive compensation to work well for me. Groups with the MPA rifle were superb up to 300 yards, around 0.25” to 0.4” (so skipped that step), even with the undesirably high ES...

So: Still need to do seating depth optimization for the MPA, primer selection, and culling cases that always perform poorly. Will give it a go, one at a time..

 

[spife7980]

Because the runout that uneven brass causes could be less than the runout thats currently on the round. If squeezing on uneven brass causes 0.003 of runout, but the round itself due to some error has 0.005 runout, then a lee crimp die could bring that runout down, making it more consistent across the board. It was hypothetical, and its very possible it could happen. Theres a lot of people who use lee crimp dies because they notice a difference. Not to mention the majority of people aren't turning their brass and some of them are still getting great results, myself included. I use a lee crimp on my AR, but not on my 6.5cm. I have yet to see where the crimp hurts me. But as always, ongoing testing is constant.

Im not advocating that a lee crimp will fix his issues, just speaking about how I envision a lee crimp working for some people.

Thats not how it works. Stay away from hypotheticals and stick to logic and solid reasoning.

I you really want to "cure" the run out on the loaded round rather than whats causing it in the first place then they make tools for that.

 

[NamibHunter]

All of that looks about like what I do, but 1-3 thou on turned brass is concerning. What’s your charge weight and what speed are you running those 140’s at? I’ve found that when your not in a node, your numbers look like you’re shootings a sbr with cheap as it comes xm193 (that shit is really whacky when it comes to consistent velocity) also how far are you setting your shoulders back. What numbers do hornady factory eld ammo give you? And last but not least what crono?

Meticulous about shoulder bump, exactly 1.5 thou on deprimed brass that has been fired and neck sized 3 times, so fully fire formed.

Labrador, compared it before with a MagnetoSpeed and they were close.

Hornady 140 match ammo shot around 2730 fps, Berger 140 was much faster around 2820. Only tested them at 100 and they shot well, with SD between 8-12 fps. ES around 35 fps.

My hand loads have SD of 6-9 fps, but ES is similar to factory ammo... around 32-36 fps. If i delete the 2-3 bad apples, i get SD of 4-5 and ES of 20-25. Trying to find the reason for the bad apples!

 

[Gustav7]

Thats not how it works. Stay away from hypotheticals and stick to logic and solid reasoning.

I you really want to "cure" the run out on the loaded round rather than whats causing it in the first place then they make tools for that.
View attachment 7205556

I appreciate the edit lol.

So how does it work? and why is my hypothetical scenario wrong? I envision a tool like this doing something similar to a lee crimp die, just a lot better. I'm also curious WHY, or HOW some people get better uniformity with a lee crimp die... generally curious here

 

[918v]

Have been struggling with high ES (35 fps or more) in my target load, even though SD is usually below 10 (typically 6-8 fps). Always 2-3 wild shots that mess up the ES.

Tried higher neck tension and the gun seems to like that more. Went to very high neck tension (5 thou), via a Whidden FL die with a full set of sizing buttons of different size, and during the seating process the (narrow) resized case neck cuts the pressure ring clean off the bullet. Bad!

Have had good success before crimping hunting bullets like the Barnes TTSX. So tried to crimp a Berger Hybrid batch to increase neck tension.... Of course, no cannelure on a Berger target bullet....

Unloaded 4 of the crimped rounds.... they all had varying degrees of damage (deep annular indentation in the bullet bearing surface). So clearly i damaged the Berger Hybrid projectiles in the crimping process.... Some had pretty ugly deep indentations and others had very little... inconsistent, so obviously this not going to work very well at distance, as BC will shift quite a bit i guess, and speed could be affected too. SD was 8.7 (pretty good) but ES was 36 fps, which is too high (even after deleting the cold bore shot).

BTW: The box of ammo shot well (0.4-0.6” groups) at 100 yards, which is a little surprising...

Does the bullet “slug” up when it accelerates at several thousand g’s down the barrel, and push the jacket outwards against the grooves, undoing some or most of the crimp indentation? Or at least making it more consistent?

Root cause: I think some cases might have been 1-2 thou shorter than others, and they get crimped very little. Hard to get them exactly the same length. The longer cases will have the most severe crimp - by quite a lot!

Measured the case length post firing and they vary by 5 thou, but that probably does not mean much.

I guess only bullets with a proper cannelure are suitable for crimping?

[.... and i guess crimping is most useful in a gas gun? BTW: Crimping did improve accuracy of my Barnes hunting load for a 30-06 bolt gun.]

Case length nothing to do with ES.

Crimp if you have something to crimp into.

Condition your necks with graphite lube to make bullet release smooth and consistent.

Adjust your load to be in the middle of its sweet spot, both on the COAL and powder charge.

 

[NamibHunter]

Thats not how it works. Stay away from hypotheticals and stick to logic and solid reasoning.

I you really want to "cure" the run out on the loaded round rather than whats causing it in the first place then they make tools for that.
View attachment 7205556

Runout: Pretty sure this is not the main problem, but open to advice! Checked runout on a Sinclair tool post firing, and they are as expected perfectly round (neck turned) with the exception of the 2-3 cases that got dropped on the concrete floor and bent the necks... i should probably carry a Sharpie pen and mark them, put them aside and use them for fouling ammo. They always end up with 3-3.5 thou runout.

The unmolested brass comes out of the Redding Type S and the Whidden non-bushing die with 0.5 to 1.5 thou for 90% of the cases. Average of 1.0 to 1.5 thou. Then seat using a Wilson inline seating die with an arbor press, which loads them very straight. There is usually a 0.5 thou degradation in case neck runout from pre to post FL sizing which is bot much. A tiny percentage of loaded rounds have runout higher than 2.5 thou and i put them aside (foulers).

 

[spife7980]

I appreciate the edit lol.

So how does it work? and why is my hypothetical scenario wrong? I envision a tool like this doing something similar to a lee crimp die, just a lot better. I'm also curious WHY, or HOW some people get better uniformity with a lee crimp die... generally curious here

Probably because the pressure curve of the chosen components prefers a bit of the pressure build up that a crimp can impart- the brass is holding that bullet just a hair longer before the bullet starts to move due to the extra grip imparted, maybe that allows for a more consistent of efficient burn of the powder. Its the same thing as some rifles liking more neck tension. And you can adjust the tension via neck bushing in your sizing die. Maybe that momentarily delayed release is just timing the bullets exit from the barrel just a smidge later which can also be done via seating depth. There are lots of factors tht go into accurate ammo. A crimper cant know where and how to straighten ammo, it can only squeeze.

 

[NamibHunter]

Case length nothing to do with ES.

Crimp if you have something to crimp into.

Condition your necks with graphite lube to make bullet release smooth and consistent.

Adjust your load to be in the middle of its sweet spot, both on the COAL and powder charge.

Will give it a go. I always use dry lube, either graphite or mica powder.

The rifle shot basically everything well up to 300, so i got a little over confident, and did not complete load development like i normally do. Who knows, maybe it can do sub 0.2” groups... but not sure i can!

Question: What is ideal neck clearance? Alpha brass is too thick for the tight chamber so i am forced to neck turn them...

Edit: To be more precise, i think MPA intends to cut a “minimum SAAMI chamber” and it is not undersize. And i think Alpha is intentionally making their brass thicker than normal to have less neck clearance in the typical oversize factory chambers... If i do not neck turn the Alpha cases, the fired round needs a little bit of finger pressure to push the bullet into the case, it does not fall freely into the case with a gap between fired neck and bullet....

 

[918v]

I like a lot of clearance .007” or more. Tight necks cause pressure problems.

 

[Nimothy]

I and I’m pretty sure other think consistency is in brass prep. There has to be something amiss. You are using a type s dies? And the expander button is removed? Now are you mixing your alpha brass with lapua? And coal isn’t a good measurement here, I’ve seen .007+ in size difference in 1 100 count box of Berger 140h

 

[Milo 2.5]

Fair point. I was planning to do seating dept optimization after finding the best speed range (node) and usually get positive compensation to work well for me. Groups with the MPA rifle were superb up to 300 yards, around 0.25” to 0.4” (so skipped that step), even with the undesirably high ES...

So: Still need to do seating depth optimization for the MPA, primer selection, and culling cases that always perform poorly. Will give it a go, one at a time..

If you are shooting quarter inch groups at 300, not sure how a seat depth change can benefit too much. If your spread is vertical, adj your charge. If it is horizontal, shoot farther and group the rifle. If it is still grouping great, find a different chrono to measure your speeds, and rule that out.
If your load shoots great to 800-1k, numbers no longer matter

 

[MarinePMI]

Crimping (IME) seem to help when:

You have excessive free bore (have to jump the bullet a lot).

Ball powder ignition issues.

Now will a crimp make generic ammo into match quality? That's up for a lot of debate (as seen above), and there is much more weight given to the "garbage in, garbage out" logic.

That being said, there are use cases where a crimp is very helpful. It just really depends. I've had loads that shot well over an inch and a half, suddenly shoot 1/2" with a crimp.

TBH, I've never tested crimped ammo (outside of .223) at long range, so I'm not entirely certain it would help ES/SD's. It'd likely just help in consistency...but consistency is a pretty broad term. A batch of ammo can consistently be mediocre, consistently accurate, or it can be consistently crap.

A crimp is just like anything else...another tool in the tool box that may (or may not) work for your particular powder/bullet/velocity. You just have to test it to find out. In a couple cartridges it has worked wonders for me, in others it just made crap worse....

 

[NamibHunter]

Replies below:

“I and I’m pretty sure other think consistency is in brass prep. There has to be something amiss.“

N: Have rechecked everything a few weeks back, and found case lengths were different, and i had a very minor carbon ring in the neck area, just before the freebore. Took care of that. Results were not materially different after that, so i don’t think the carbon ring extended far enough down to pinch the neck.

“You are using a type s dies? And the expander button is removed?”

N: Lately i have been using the Whidden non-bushing die (with a set of sizing buttons) and concentricity and measured neck “tension” was pretty consistent. The die is not mangling the brass. But the button is in place.

N: Have used the Redding Type S full length sizing die until recently. Sizing button was left in. What are the benefits of removing it?

“Now are you mixing your alpha brass with lapua?”

N: No sir, i do not mix brass from different brands or different shipments of the same brand. All batches are serialized with a small number engraved on the side (web area), to make sure they never get mixed up.

Tumble brass every time in a mix of corn cob plus walnut media, with a spoonful of mineral spirits mixed into the media plus a teaspoon amount of Nushine car wax (aim is to prevent bullet weld, which was a major problem before). I Keep brass together from one shipment, weight sorted into batches of 50 with a range of 1.5 grain or less.

Check variations in neck thickness with a micrometer and culled them if off by more than 1 thou. Should i cull more aggressively, and what is a good spec?

Neck turned all my batches, to 12.2 thou +- 0.2 [Except for the latest batch of Lapua brass (derived from Berger factory ammo that shot well). Trying to see if i can avoid neck turning. Neck turning is a lot of work.]

Primer pockets were cut to the same depth via a Lyman case prep center.

Case length is cut to the length of the shortest case in the batch with a Wilson lathe type cutter to within about 1 thou. Necks are chamfered and deburred.

Flash holes are untouched. Should i chamfer that as well on the inside if the case? Did not see a burr with my bore scope, but might have missed the odd one or two. Also i believe Lapua brass has drilled flash hole, so that should not be an issue?

“And coal isn’t a good measurement here, I’ve seen .007+ in size difference in 1 100 count box of Berger 140h”

N: Fully agree. I use a Hornady bullet comparator, and Berger Hybrid bullets are seated to within 1.5 thou. Seating depth is not yet optimized, but will do that next.

N: Maybe my cleaning regime is not adequate? I use WipeOut with accelerator now (twice over), but in the past i cleaned every 150 to 200 shots with Birchwood Casey BoreScrubber, now i clean after ever range session. What is best?

 

[Nimothy]

Replies below:

“I and I’m pretty sure other think consistency is in brass prep. There has to be something amiss.“

N: Have rechecked everything a few weeks back, and found case lengths were different, and i had a very minor carbon ring in the neck area, just before the freebore. Took care of that. Results were not materially different after that, so i don’t think the carbon ring extended far enough down to pinch the neck.

“You are using a type s dies? And the expander button is removed?”

N: Lately i have been using the Whidden non-bushing die (with a set of sizing buttons) and concentricity and measured neck “tension” was pretty consistent. The die is not mangling the brass. But the button is in place.

N: Have used the Redding Type S full length sizing die until recently. Sizing button was left in. What are the benefits of removing it?

“Now are you mixing your alpha brass with lapua?”

N: No sir, i do not mix brass from different brands or different shipments of the same brand. All batches are serialized with a small number engraved on the side (web area), to make sure they never get mixed up.

Tumble brass every time in a mix of corn cob plus walnut media, with a spoonful of mineral spirits mixed into the media plus a teaspoon amount of Nushine car wax (aim is to prevent bullet weld, which was a major problem before). I Keep brass together from one shipment, weight sorted into batches of 50 with a range of 1.5 grain or less.

Check variations in neck thickness with a micrometer and culled them if off by more than 1 thou. Should i cull more aggressively, and what is a good spec?

Neck turned all my batches, to 12.2 thou +- 0.2 [Except for the latest batch of Lapua brass (derived from Berger factory ammo that shot well). Trying to see if i can avoid neck turning. Neck turning is a lot of work.]

Primer pockets were cut to the same depth via a Lyman case prep center.

Case length is cut to the length of the shortest case in the batch with a Wilson lathe type cutter to within about 1 thou. Necks are chamfered and deburred.

Flash holes are untouched. Should i chamfer that as well on the inside if the case? Did not see a burr with my bore scope, but might have missed the odd one or two. Also i believe Lapua brass has drilled flash hole, so that should not be an issue?

“And coal isn’t a good measurement here, I’ve seen .007+ in size difference in 1 100 count box of Berger 140h”

N: Fully agree. I use a Hornady bullet comparator, and Berger Hybrid bullets are seated to within 1.5 thou. Seating depth is not yet optimized, but will do that next.

N: Maybe my cleaning regime is not adequate? I use WipeOut with accelerator now (twice over), but in the past i cleaned every 150 to 200 shots with Birchwood Casey BoreScrubber, now i clean after ever range session. What is best?

Nah man you’re doing way more that I am and my old 2400rd creed has had two kids it’s entire life. Not sub 10es. If your seating depth is consistent I might have a Smith look at the rifle. Now this is second hand knowledge and I’m not going to stand by it but I e heard that some mpa factory cut chambers have sucked. Not sucked to the point of new barrel so to speak but definitely needed attention. I’d hate to tell you to drop that thing off at a smith but dude your handloads should do better than 30es with everything your doing.

 

[Dthomas3523]

Are you seating with a regular press, or inline dies/arbor press?

Also, how clean are you getting the inside of the necks?

Now that I’m using a hydro press for seating, I’ve noticed that neck tension and seating pressure aren’t always the same. I’ve had times where less neck tension (using size of mouth) still takes more PSI to seat than some brass with more neck tension.

I can now pretty much predict which rounds will cause a higher ES based on the PSI of seating pressure.

I will set the outliers that take noticeably more pressure to seat off to the side. I’ll shoot a string and have a low two or single digit ES. I’ll then throw the higher PSI round in and my ES will double or more.

Cleaner (especially factory new) necks will require more seating pressure (I’m assuming because more friction) than once fired necks that are sized the same. Due to the carbon that is now inside the fired neck. So, if you are getting some cases too clean, you may have some rounds with higher seating pressure even though your neck tension is the same.

If you’re using a standard press, you’ll almost never be able to feel the difference in 10psi and 60 psi of seating pressure.

 

[NamibHunter]

Replies below:

“Are you seating with a regular press, or inline dies/arbor press?”

N: Inline Wilson seater die with a K&M arbor press. I put aside anything with concentricity worse than 2.5 thou. Average is often 1 to 1.5 thou. Should i pick a threshold of 1.5 thou perhaps?

N: However: Seating depth consistency can vary, sometimes by as much as 3 thou, as the arbor press doesn’t have a lot of force.... so i need to check each of them (takes time), and then reseat/thump the handle multiple times to ensure consistent seating dept.... Then get base to ogive within 1.5 thou (some of that delta is bullet variarion). But i have not yet found another die that seats as straight in my RCBS press.... So: Maybe my BR seater die is causing more problems than it is solving? What is the best seater die?

“Also, how clean are you getting the inside of the necks?”

N: Tumble for 2 hours, in a mix of walnut and corn cob, and there is a lot of carbon left in the necks, and even in the primer pockets. Outside of cases are very clean due to addition of mineral spirits (meant to keep the dust down, but it dissolves the carbon too). Should i stop doing that? Since it is a hydrocarbon (a light oil), does that affect the powder that comes into contact with the microscopic layer of oil that is left on the case post tumbling? Also a tiny amount of car wax is used to coat the cases, to avoid bullet weld, which was a big problem before (and the addition of mineral spirits and Nushine helped a lot to prevent/reduce bullet weld). Gulf Coast. Very humid climate. I will do another test and load bullets very long, wait a month and then see what is the required seating force to reseat them to the correct base to ogive. Maybe that is driving up my ES.

“Now that I’m using a hydro press for seating, I’ve noticed that neck tension and seating pressure aren’t always the same. I’ve had times where less neck tension (using size of mouth) still takes more PSI to seat than some brass with more neck tension.”

N: Yep, I have had the same experience with the K&M arbor press with the force measurement tip. The press measures pounds of seating force as the bullet glides into the neck (which varies a lot as it moves down), so i try to record the peak force required (in pounds) to seat the bullet. Peak force usually varies about 30% even with neck turned and annealed brass, with dry lube, or brass that has had an expander ball or mandrel die open them up again. I did polish the inside of the necks with fine steel wool. Made no difference.

N: I wonder if peak force is NOT what really matters here, which is often achieved when the pressure ring on the bullet slips past the false shoulder on the neck left by the bushing (the entire neck is not sized)? Maybe it is the lesser force needed to just get the bullet moving (long before the pressure ring on the bullet will hit the false shoulder again on the way out, and this number is often much lower). What should i record? Should i seat twice, and record only the last amount to reseat the bullet the last 20 thou? (Which is twice the work ☹)... but if that works, i will spend the time!

“I can now pretty much predict which rounds will cause a higher ES based on the PSI of seating pressure.”

N: I was hoping for the exact same result but did not get it! Recorded peak force with a Sharpie on the case, and plotted speed vs peak force, and found zero correlation! Weird. So maybe peak force is irrelevant... How do you do it?

N: I will set aside the more difficult to reseat rounds, and use for fouling shots, try to infer bullet starting force, and see how much that helps.

N: Also: Now using the Whidden non-bushing sizer die (i can control neck tension with the choice of button, all are 1 thou apart), so the false shoulder is not present anymore... and maybe that will help. [I realize some people are deeply sceptical of sizers with buttons....not meaning to start a controversy!!]

“I will set the outliers that take noticeably more pressure to seat off to the side. I’ll shoot a string and have a low two or single digit ES. I’ll then throw the higher PSI round in and my ES will double or more.”

N: This is EXACTLY what i am chasing!! Never ever got an ES below 23 fps for a large batch (total of maybe 20 rounds), only seen it twice for a 5 shot string during load development, which does not count. For 35-50 round strings i get 32-36 fps ES. Consistently!

N: Just to clarify, do you get an SD of 2.x where x is a low number, and an ES < 10 fps? If so you have my respect! That is phenomenally good!! What was the major contributing factor that got you there? How do you clean your brass and what steps do you follow for brass prep?

“Cleaner (especially factory new) necks will require more seating pressure (I’m assuming because more friction) than once fired necks that are sized the same. Due to the carbon that is now inside the fired neck. So, if you are getting some cases too clean, you may have some rounds with higher seating pressure even though your neck tension is the same.”

N: Understood. I used to over clean my brass, would forget them in the tumbler for 4-6 hours and the inside necks would be cleaned down to the bare brass surface, but have purchased a timer, and now run them for exactly 2 hours. Is that too still much? What is the right amount...

“If you’re using a standard press, you’ll almost never be able to feel the difference in 10psi and 60 psi of seating pressure.”

N: Agreed. I gave up on screw-in seater dies that requires a standard press. I have an RCBS Rock Chucker press. Don’t feel like there is any slop, but who knows.... Concentricity was not great, around 3-6 thou, so gave up on it. Maybe the press, maybe the die (tried several), or maybe the operator putting the bullets skew in the neck... Willing to try again, so what would you guys recommend.

N: Wilson arbor setup seats very straight, average is 1.5 thou bullet concentricity, but
any brass with previously bent necks (for example dropped on concrete floor) gives 2-3.5 thou. Sizing operation improved these necks, but they need to be fired to be totally round again.... i will be even more meticulous, or OCD, and mark them with a sharpie and keep them apart.

N: Open to any good idea.... Bought the equipment and added a lot of steps as i thought i needed to do that to load ‘Olympic’ level ammo, but so far it is barely better than good quality factory ammo. Berger and Federal Match ammo quite often have equal or close numbers.... Very aggregating....

N: I don’t think it is the MPA rifle. It shoots rediculously small groups at 100. All four of my barrels have given the same high ES. Must be the ammo, or my lack of periodic cleaning.... or a ghost in the machine!

 

[NamibHunter]

Nah man you’re doing way more that I am and my old 2400rd creed has had two kids it’s entire life. Not sub 10es. If your seating depth is consistent I might have a Smith look at the rifle. Now this is second hand knowledge and I’m not going to stand by it but I e heard that some mpa factory cut chambers have sucked. Not sucked to the point of new barrel so to speak but definitely needed attention. I’d hate to tell you to drop that thing off at a smith but dude your handloads should do better than 30es with everything your doing.

N: Thanks for the reply. I had a good bore scope in the chamber, and all looks well to my untrained eye.... MPA rifle shoots 0.2 to 0.3” three shot groups at 100, and 0.35-0.45” five shot groups. Second most accurate rifle i have ever owned. [Aside: Best three shot group measured 0.08” but that was likely just luck. One single good three shot group does not count. Five shot aggregate is 0.41” so far, which is ‘good’ given my current skill level and total lack of wind reading skills....]

Even 300 yard groups are often 0.3-0.4 MOA, but at 300 (Edit: My apologies, 600 was a typo) there is a lot of vertical stringing, around 6-8”. Either ES is too high (likely the primary cause), or my amateur attempt at positive compensations needs to be redone....

Edit: First two pics are three shot groups at 100 in a 6-8 mph wind if i recall correctly, last one is a three shot group at 300 (NOT 600!) yards. Same wind. Yes these are amongst my best results so far. [I did not bother to take a photo of the 0.08” group, it was slightly oval, looked like a 2 shot group, and everybody will call me a damn liar... ?]

BTW: I find that i aim more accurately if i shoot at diamond shaped targets or very small circles, rather than large circles. Helped my groups to improve about 0.15 MOA.... Try it!

 

[NamibHunter]

.... and apologies for the mile long post! Trying to answer the many good questions and be completely accurate....

 

[NamibHunter]

If you are shooting quarter inch groups at 300, not sure how a seat depth change can benefit too much. If your spread is vertical, adj your charge. If it is horizontal, shoot farther and group the rifle. If it is still grouping great, find a different chrono to measure your speeds, and rule that out.
If your load shoots great to 800-1k, numbers no longer matter

No, i probably explained badly, i get 1/4-1/3” groups at 100, 1-1.5” groups at 300 yards (0.3 to 0.5 MOA). Sorry for the confusion.

“Only” problem is vertical stringing at 400 and beyond. With the high ES it will not work well at 1000 yards, which is the goal here...

 

[Nimothy]

N: Thanks for the reply. I had a good bore scope in the chamber, and all looks well to my untrained eye.... MPA rifle shoots 0.2 to 0.3” three shot groups at 100, and 0.35-0.45” five shot groups. Second most accurate rifle i have ever owned. [Aside: Best three shot group measured 0.08” but that was likely just luck. One single good three shot group does not count. Five shot aggregate is 0.41” so far, which is ‘good’ given my current skill level and total lack of wind reading skills....]

Even 300 yard groups are often 0.3-0.4 MOA, but at 300 (Edit: My apologies, 600 was a typo) there is a lot of vertical stringing, around 6-8”. Either ES is too high (likely the primary cause), or my amateur attempt at positive compensations needs to be redone....

Edit: First two pics are three shot groups at 100 in a 6-8 mph wind if i recall correctly, last one is a three shot group at 300 (NOT 600!) yards. Same wind. Yes these are amongst my best results so far. [I did not bother to take a photo of the 0.08” group, it was slightly oval, looked like a 2 shot group, and everybody will call me a damn liar... ?]

BTW: I find that i aim more accurately if i shoot at diamond shaped targets or very small circles, rather than large circles. Helped my groups to improve about 0.15 MOA.... Try it!


View attachment 7206339
View attachment 7206341
View attachment 7206347

I agree with your diamond targets they are easier to put crosshairs on for sure. You have and hornady once fired cases? Could you just neck size them if they chamber and seat the bullet to 20 thou off, with 2 thou neck tension, and run say 41.5 of h4350 in it like 10 rounds over a crono. And see what the es is then. That would narrow it down to your sizing die. If needed I’ll send you a lee collet die to do the test if you send it back lol. I can also send you a few once fired hornady cases that have been annealer but not sized to see if they fit. That is if you don’t have any. Your rifle has me perplexed man. I’ve had some dudes on another forum help me out when my bra was sucking and I always try and pay it forward if I can

 

[Rocketmandb]

I'm curious, have you tried not crimping? You might want to get everything as consistent as possible without crimping, then reintroduce it and see what the impact is.

Additionally, seating depth can have an impact on ES. I was having a hell of a time getting to "my" load on my 6mm BRA, so shifted my attention to seating depth. I got that locked down then turned to getting the right load. I zeroed right in.

Particulars:
- 6mm BRA
- Lapua brass
- No crimp
- No neck turn
- No bullet lube - going to start playing with this soon, though.
- ES's in the 4 range, give or take
- I can get groups down to just over 1/2" at 300 if I do my part.

Also, you mention getting within .04 gr using the A&D 120. With 4350, you should be able to get to exactly your target load showing on the scale. Not that it will make a huge difference - maybe 3-4 fps, but you should be able to get there and will obviously help a little with ES. Even on larger powders (e.g. H1000, Retumbo, RL 26), I hit -0/+.02 gr.

 

[NamibHunter]

I agree with your diamond targets they are easier to put crosshairs on for sure. You have and hornady once fired cases? Could you just neck size them if they chamber and seat the bullet to 20 thou off, with 2 thou neck tension, and run say 41.5 of h4350 in it like 10 rounds over a crono. And see what the es is then. That would narrow it down to your sizing die. If needed I’ll send you a lee collet die to do the test if you send it back lol. I can also send you a few once fired hornady cases that have been annealer but not sized to see if they fit. That is if you don’t have any. Your rifle has me perplexed man. I’ve had some dudes on another forum help me out when my bra was sucking and I always try and pay it forward if I can

@Nimothy: Believe in the “pass forward” philosophy of life. Work in engineering. Many people have trained me over the years, and i am training a bunch of bright youngsters.... probably working myself out of a job, but retirement is beckoning anyway..

I have the 4 die Lee set, and have used their superb Collet neck sizer die before, with very good success. Can give it a try. That will remove the effect of the FL die... Clever.

I have a box of 50 Lapua once fired (so cases are fire formed to the MPA chamber, and so far unsized) derived from firing Berger 140 factory ammo. Not neck turned. Presume that will work equally well (Lapua SRP brass)? [Also have 40 Hornady cases from the 140 ELDX Match ammo (that shot well).]

I usually hit pressure signs (full moon ejector marks) before i get to 41.5 but will pick a value 0.3 below max. Chamber is minimum SAAMI dimensions so tighter than most rifles. Ambient temp is low enough this time of year.

 

[NamibHunter]

Replies below.

“I'm curious, have you tried not crimping? You might want to get everything as consistent as possible without crimping, then reintroduce it and see what the impact is.”

N: Fair point. Yes i tried 4 boxes of hand loads (50 each) without crimping, and every time got SD below 10, ES well above 30 fps. Best load had high neck tension (3 thou), wanted to go higher.... But the prior comment that seating depth could achieve the same ignition delay makes sense. Will try to optimize seating depth soon.

BTW: I know a little bit about stats and the data i have shows close to a Normal / Gaussian distribution. I don’t think my high and low speed shots are true “outliers” (i. e. not belonging to a different probability distribution), just bad luck that is bound to happen now and then. So if i want to get ES below 25 fps, then we have to assume that for sample size of 50-100 rounds, that ES could quite likely be 4xSD to 5xSD, so my SD target has to be 5-6 fps, and currently i am at 6-9 fps. So the current load is not terrible, but not yet a 1000 yard load.

“Additionally, seating depth can have an impact on ES. I was having a hell of a time getting to "my" load on my 6mm BRA, so shifted my attention to seating depth. I got that locked down then turned to getting the right load. I zeroed right in.

Particulars:
- 6mm BRA
- Lapua brass
- No crimp
- No neck turn
- No bullet lube - going to start playing with this soon, though.
- ES's in the 4 range, give or take
- I can get groups down to just over 1/2" at 300 if I do my part.”

N: OK now i am a little jealous... That is absolutely superb! So ES around 4 for a shot string of 5?

N: Will be happy if i can get 3x your numbers. I might not be in the center of the node anymore. Barrel has sped up since i started shooting it. Will redo a quick load development tomorrow morning (5 rounds each), drive the 5 miles home and load 50 rounds of the winning load in 90 minutes, then gl back and shoot that. Can reseat at the range and optimize seating depth while shooting. Very conven

“Also, you mention getting within .04 gr using the A&D 120. With 4350, you should be able to get to exactly your target load showing on the scale. Not that it will make a huge difference - maybe 3-4 fps, but you should be able to get there and will obviously help a little with ES. Even on larger powders (e.g. H1000, Retumbo, RL 26), I hit -0/+.02 gr.”

N: Yep, FX120 scale can do that, once warmed up. Means turning off the AC, to stop the draft. Will do so.

 

[Nimothy]

@Nimothy: Believe in the “pass forward” philosophy of life. Work in engineering. Many people have trained me over the years, and i am training a bunch of bright youngsters.... probably working myself out of a job, but retirement is beckoning anyway..

I have the 4 die Lee set, and have used their superb Collet neck sizer die before, with very good success. Can give it a try. That will remove the effect of the FL die... Clever.

I have a box of 50 Lapua once fired (so cases are fire formed to the MPA chamber, and so far unsized) derived from firing Berger 140 factory ammo. Not neck turned. Presume that will work equally well (Lapua SRP brass)? [Also have 40 Hornady cases from the 140 ELDX Match ammo (that shot well).]

I usually hit pressure signs (full moon ejector marks) before i get to 41.5 but will pick a value 0.3 below max. Chamber is minimum SAAMI dimensions so tighter than most rifles. Ambient temp is low enough this time of year.

I would try the once fired lapua that’s non neck turned, but first I would find the lands in that rifle and load .020 off. How many rounds are on this barrel?

 

[Nimothy]

What’s your velocity at your max load without pressure? What velocity does factory eld run at?

 

[Rocketmandb]

Replies below.
Will try to optimize seating depth soon.

More food for thought:

A friend of mine was having some fits with ES on his new 338. He did the same thing that I did with finding a decent load then shoot groups for seating depth. His numbers went from truly abysmal to somewhat egregious to the numbers you're shooting for in fifteen thousandths (.005 increments).

N: OK now i am a little jealous... That is absolutely superb! So ES around 4 for a shot string of 5?

Sorry, I misspoke (mistyped) - my SD (not ES) is usually around 4, with ESs in the 8-10 range. With that said, with a couple loads that didn't group as well, I would routinely get ES in the 5-6 range and SDs in the 2-3 range. This was with a 29.2 gr (H4895 - 105 Hybrid) load. I took a pic of the Labradar on one particularly good group during testing - also, I usually shoot 5-shot groups during validation, one shot in this string didn't register.

Based on just SD/ES, this should be a winner, right? This load grouped just "okay" though, so this is when I went back to the drawing board and played with seating depth. Landed on .025" then went back to the beginning of load development. Finally landed on 30.7 gr - I like the velocity a lot more with this load at ~2950 fps than the 2830 I got with the lower load. This new load gives me those SDs in the 4 range. Not nearly as consistent as the 29.2 load, but then I'm getting groups like this at 300 yards.

 

[J McGriddle]

I had a similar problem and found that annealing brass every other firing (every firing if I have the time) was the only way for me to get to single digit ES for a 5 shot sample. It's easy to get caught up in the minutiae but at the end of the day putting rounds on target is all that matters, to me anyway.

 

[Rocketmandb]

I had a similar problem and found that annealing brass every other firing (every firing if I have the time) was the only way for me to get to single digit ES for a 5 shot sample. It's easy to get caught up in the minutiae but at the end of the day putting rounds on target is all that matters, to me anyway.

Good point and something I left out of my reply. I anneal every time.

 

[NamibHunter]

What’s your velocity at your max load without pressure? What velocity does factory eld run at?

With H4350 and Berger Hybrid 140 reloads i get a max speed of 2765 when “half moons” show up in summer (partial or faint ejector marks). It has a 26” MPA barrel. Barrel looks good inside via bore scope.

Hornady 140 ELDM match ammo ran about 2720-2730, but barrel was not broken in yet at that time, and shot well. Did not see pressure signs. Expect is is faster now, but need to order a few boxes.

Berger factory 140 ammo was much faster than Hornady during the break-in period, but some showed pressure signs, with a few ejector marks, flat primers, and two pierced primers. [Large firing pin and SRP brass, will need to get the firing pin bushed.]

 

[NamibHunter]

Good point and something I left out of my reply. I anneal every time.

Over thr past year i have annealed every reload via the AMP machine, using Aztec mode. Now anneal every three reloads, just feels like the gun shoots non-annealed brass better (2x higher seating force if you skip annealing).

Also: AMP machine makes the surface finish of the neck very rough (sand papar feel), at least on the outside, and found that i had to tumble it a second time to remove it. That might remove too much carbon inside the neck. Bullets look like they were scoured with sandpaper when i unloaded a few. Also necks got very soft, and bullet seating force would be way lower than i have seen with gas flame annealing before (checked temps via Tempilaq).

I might have to go back to gas flame annealing, which did not have these problem (or at least not as pronounced, or did not notice it).

Happy to try gas flame annealing... ? Just a little sceptical of the AMP machine these days...

 

[NamibHunter]

More food for thought:

A friend of mine was having some fits with ES on his new 338. He did the same thing that I did with finding a decent load then shoot groups for seating depth. His numbers went from truly abysmal to somewhat egregious to the numbers you're shooting for in fifteen thousandths (.005 increments).




Sorry, I misspoke (mistyped) - my SD (not ES) is usually around 4, with ESs in the 8-10 range. With that said, with a couple loads that didn't group as well, I would routinely get ES in the 5-6 range and SDs in the 2-3 range. This was with a 29.2 gr (H4895 - 105 Hybrid) load. I took a pic of the Labradar on one particularly good group during testing - also, I usually shoot 5-shot groups during validation, one shot in this string didn't register.

View attachment 7206803

Based on just SD/ES, this should be a winner, right? This load grouped just "okay" though, so this is when I went back to the drawing board and played with seating depth. Landed on .025" then went back to the beginning of load development. Finally landed on 30.7 gr - I like the velocity a lot more with this load at ~2950 fps than the 2830 I got with the lower load. This new load gives me those SDs in the 4 range. Not nearly as consistent as the 29.2 load, but then I'm getting groups like this at 300 yards.

View attachment 7206804

Thanks for the clarification. You are Achieving what i am aiming for, so will follow your process.

I sometimes hear that the good / “best” 6 mm cartridges like 6BRA or 6 Dasher tend to get better ES than 6.5 CM. Am i chasing an unrealistic ES goal with the 6.5 caliber? Should i switch caliber... pretty major investment though....

 

[Nimothy]

Thanks for the clarification. You are Achieving what i am aiming for, so sill follow you process.!

I sometimes hear that the good / “best” 6 mm cartridges like 6BRA tends to get better ES than 6.5 CM. Am i chasing an unrealistic ES goal with the 6.5 caliber? Should i switch caliber... pretty major investment though....

No I get sub 10 out of a bart 5r on a trued Remington and I shoot 147’s how you shoot 140’s speed wise with no pierced primers and no ejector marks. At what length does a Berger 140 touch the lands? I might be wasaay off here, but what if your chamber is throated for more of a tangent type bullet and your setting up your cases way to short and causing the pressure spike that Is throwing off your es. It all seems to boil down to seating depth. I’m think I’m now on the same page as all the other folks on this thread. Load them .020 off even if they are more than mag length and give it a go single feed if you have to.