Guys, I have a problem I bet/hope you can help...

[RonR]

I'm reloading very carefully and unfortunately the velocity standard deviation and velocity extreme spread varies inconsistently from 7.5 fps to 60 fps - it's just all over the place and unpredictable.

I'm sure you'll want details so here ya go.

cases: new or once reloaded Hornady
bullet: .223 Rem Nosler 70 gn RDF
powder: Reloader 15 and Ramshot TAC
primers: Federal GMM

procedure:
sort cases by weight
resize cases with Hornady Lock N Load Match dies with 0.254 neck bushing
measure and trim cases as needed to 0.002"
light chamfer mouth inside and out
uniform flash holes
prime case
dispense powder from RCBS Chargemaster
confirm weight on beam balance scale
load powder in case
seat bullet to 2.26 COAL to fit in AR mag, although the mag goes in a MVP LR
Then measure the case to ogive and seat every bullet by that measurement to within 0.002"
Check/set concentricity to no more than 0.002"

Imagine after all that, getting SDs all over the place from 7.5 fps to 60 fps - completely unpredictable

The gun is a Mossberg MVP LR with (and without) a Liberty Triumph suppressor - suppressor on or off doesn't seem to make any difference.

I thought maybe the bullets are getting set back by chambering, so I very carefully hand loaded 3 sets of 5 rounds into the chamber and closed the bolt . I saw no difference.

What in the world am I doing wrong?

Many thanks for your help and thoughts!

 

[mdmp5]

With either powder is the same result?

 

[RonR]

With either powder is the same result?

Thanks!

Essentially the same.

I'm inclined to think it's something going on with the gun. I can't imagine why such carefully loaded rounds come out of the barrel at such wide spread velocities???

Would perhaps a marginal firing pin spring produce inconsistent primer strikes and explain the variation?

 

[Deleted member 113831]

I have never used RL15, but I will tell you that TAC does not like standard primers. CCI 450's or similar for that powder.

 

[winniedonkey]

Have you tested factory loads? How consistent are the RDFs? Mine (175)were good on weight but differed in CBTO would be different. These were around first release. My Hornady are GTG. How far is your jump?

 

[RonR]

I have never used RL15, but I will tell you that TAC does not like standard primers. CCI 450's or similar for that powder.

Thanks! That's good to know!

 

[RonR]

Have you tested factory loads? How consistent are the RDFs? Mine (175)were good on weight but differed in CBTO would be different. These were around first release. My Hornady are GTG. How far is your jump?

I have tested factory loads. The SD's are anywhere from 20-30 fps which is not what I'm looking for, but it's better than what I'm getting.

The RDFs seem to be pretty consistent using the ogive as the measuring point. I had maybe two that were a bit long so I just dialed in the amount into the seating stem and seated it the same as the others.

The MVP LR has a headspace of 2.300". That's from the base of the case to the tip of the bullet. From the COAL, I measured case to ogive. As I recall that should have given me a jump of about 0.031". I'm limited on what I can set the COAL to because the MVP LR feeds from an AR magazine which typically is about 2.260" overall. So I pushed it to 0.09" over the 2.260" mark and it didn't cause any problems.

 

[supercorndogs]

Did you mix your once fired and new? How did you work up your load? Did you run a length test on target or over the chromo.

 

[Rhed]

Try making a a dummy round or two. Do your exact workflow, minus the powder and primer. Load it in the mag, pop in the rifle, engage the bolt, then extract the round. Check the OAL again and see if there’s any bullet creep. If there is creep, that could lead to inconsistency in SD’s. Then if that’s the case, neck tension with a small taper crimp should help.

 

[winniedonkey]

I have tested factory loads. The SD's are anywhere from 20-30 fps which is not what I'm looking for, but it's better than what I'm getting.

The RDFs seem to be pretty consistent using the ogive as the measuring point. I had maybe two that were a bit long so I just dialed in the amount into the seating stem and seated it the same as the others.

The MVP LR has a headspace of 2.300". That's from the base of the case to the tip of the bullet. From the COAL, I measured case to ogive. As I recall that should have given me a jump of about 0.031". I'm limited on what I can set the COAL to because the MVP LR feeds from an AR magazine which typically is about 2.260" overall. So I pushed it to 0.09" over the 2.260" mark and it didn't cause any problems.

ASC SS mags give you a 2.316 ish COAL FYI. Have worked great for me. Also I can recall there were quiet a few people on here who had issues getting their 70 RDF to shoot well. Try the search and see if there was a theme to why. Don't recall if there was one. Worst case is try another bullet. Good luck to you.

 

[PinesAndProjectiles]

Are all rounds fired over a chrony? What are your charge weights? Are you not on a node? Does it group?

 

[RonR]

Did you mix your once fired and new? How did you work up your load? Did you run a length test on target or over the chromo.

No mixing, all cases new or all cases once fired, all cases sorted by weight. It's kind of exasperating - seems like I'm doing everything right, but I'm obviously missing something???
I did ladder tests and incremented by 0.5 gn per step.

I chrono every round with LabRadar.

By length test on target, you mean seating depth?

 

[RonR]

Try making a a dummy round or two. Do your exact workflow, minus the powder and primer. Load it in the mag, pop in the rifle, engage the bolt, then extract the round. Check the OAL again and see if there’s any bullet creep. If there is creep, that could lead to inconsistency in SD’s. Then if that’s the case, neck tension with a small taper crimp should help.

I did that and the bullet kept pulling out of the case. I then went to the Hornady thingy that measures headspace, got 2.30"

Thanks for the thought - I'm gonna take another run at headspace using a different method and try adjusting the bullet seating depth.

 

[RonR]

ASC SS mags give you a 2.316 ish COAL FYI. Have worked great for me. Also I can recall there were quiet a few people on here who had issues getting their 70 RDF to shoot well. Try the search and see if there was a theme to why. Don't recall if there was one. Worst case is try another bullet. Good luck to you.

Many thanks!

I'll sure keep the ACS mags in mind. Before I spend more (seems like there's no end to reloading) I want to try to eliminate everything else I can.

And thanks for the tip about the Noslers - I'll have to look that up.

 

[RonR]

Are all rounds fired over a chrony? What are your charge weights? Are you not on a node? Does it group?

All rounds are clocked by a LabRadar. Charge weight for Reloader 15 with 70 gn has been 22.5, 23, 23.5, 24 grains. With Reloader 15 and 77 gn SMKs they are, 23, 23.5, 24.

No, none of anything I've loaded groups well. Well, that's not entirely true, I have had some 1 MOA groups, but even then the SDs are high. I've had good groups with high SD's and 2-3 MOA groups with SDs of 18 fps and below - just really perplexing.

If being on a node would help, I'm obviously not on it. LOL. What's a node and how do I know if I'm on one?

Thanks!

 

[TxSteel]

If being on a node would help, I'm obviously not on it. LOL. What's a node and how do I know if I'm on one?

Thanks!

load 1 round at increasing charge weights by .2 to .3 grains until you get to 10 rounds. Last one should be your max load. Shoot using the lab radar and look for a flat spot. Pick the charge in the middle of the flat spot, and load 5 or 10 to confirm.

 

[MarinePMI]

RDF's usually like a healthy jump (like .050").

 

[Hawk in WY]

What do the two points under “Seat Bullet to 2.26 COAL” mean?

What are you doing to the cartridge after seating the bullet?

If the second last point means what I think it does and I ignore the third last some bullets touching the lands and some not would explain what you are seeing.

 

[Mike_in_FL]

Nobody could get very good accuracy out of these in ARs, same thing in your case, limited by mag length. My 700 with a Douglas barrel is something crazy like 2.400 to the lands with these so it sounds like that rifle has a fairly short throat. Maybe you should try seating them deeper to increase the jump as was suggested? I'd also try some 8208XBR before I bought new mags.

 

[Pvt.Donut]

What is your case neck thickness? 0.254" seems rather large unless your case necks are 0.014" or larger.

 

[supercorndogs]

All rounds are clocked by a LabRadar. Charge weight for Reloader 15 with 70 gn has been 22.5, 23, 23.5, 24 grains. With Reloader 15 and 77 gn SMKs they are, 23, 23.5, 24.

No, none of anything I've loaded groups well. Well, that's not entirely true, I have had some 1 MOA groups, but even then the SDs are high. I've had good groups with high SD's and 2-3 MOA groups with SDs of 18 fps and below - just really perplexing.

If being on a node would help, I'm obviously not on it. LOL. What's a node and how do I know if I'm on one?

Thanks!

You are making big jumps in charge weight in a small case. Your node windows probably will not be half a grain wide in a 223.

Headspace is the distance from the case head to the datum line on the shoulder. Not your OAL or bast to ogive measurement. If you are bumping your shoulders too far it will cause other problems.

If your gun is pulling the bullets out of the case, you may be jammed into the rifling on some or all of your rounds.

 

[Rhed]

I did that and the bullet kept pulling out of the case. I then went to the Hornady thingy that measures headspace, got 2.30"

Thanks for the thought - I'm gonna take another run at headspace using a different method and try adjusting the bullet seating depth.

So you are having bullet creep? Btw, measure to ogive instead. Cause most bullet lengths will vary cause not all is same. Measuring OAL will give inconsistent readings because of this. Unless you sort and/or doing something to the Meplat. Weights of bullet will vary too. So sorting is recommended if your doing precision shooting at long distance.

 

[Rhed]

Also something to give thought too. While seating depth is important, for me, I like seating bullets till I feel a little crunch of the powder. While being consistent with that depth after that. The reason being, powder having some space in the case to move around will have inconsistent case pressure. Though we don’t want too seat too deep like smashing or compacting the powder too much with the bullet, that might lead to dangerous case pressure. Anyways lots thought to think about while reloading. In the end it’s all preference. But that’s the whole beauty of it. We can make ammo far exceeding accuracy to a factory round. Well then of course 99.5% is the operator overall.. lol

 

[Hawk in WY]

[QUOTE="r

The MVP LR has a headspace of 2.300". That's from the base of the case to the tip of the bullet. From the COAL, I measured case to ogive. As I recall that should have given me a jump of about 0.031". I'm limited on what I can set the COAL to because the MVP LR feeds from an AR magazine which typically is about 2.260" overall. So I pushed it to 0.09" over the 2.260" mark and it didn't cause any problems.[/QUOTE]

So if I understand this you are loading 2.35 COAL and you measure the lands at 2.30. With measurement error you have some bullets in the lands and some not. Back off 20 thousands and see what happens.

Please also read this:


In firearms, headspace is the distance measured from the part of the chamber that stops forward motion of the cartridge (the datum reference) to the face of the bolt. Used as a verb, headspace refers to the interference created between this part of the chamber and the feature of the cartridge that achieves the correct positioning. Different cartridges have their datum lines in different positions in relation to the cartridge.[1] For example, 5.56 NATO ammunition headspaces off the shoulder of the cartridge, whereas .303 Britishheadspaces off the forward rim of the cartridge.

Good luck

 

[RonR]

What do the two points under “Seat Bullet to 2.26 COAL” mean?

What are you doing to the cartridge after seating the bullet?

If the second last point means what I think it does and I ignore the third last some bullets touching the lands and some not would explain what you are seeing.

First, Thanks to all for the help. Didn't mean to disappear on you, got tied up.

Here's what I meant by COAL. I used a Hornady Lock N Load O.A.L. Gauge to find the seating depth with the bullet I was using. After finding where the bullet touches the lands, I measured the length from case base to bullet tip. I then removed the bullet from the gauge and placed it in a sized case. I seated it until it was exactly the same length case base to bullet tip. I then used a Hornady headspace gauge to measure the case base to ogive and saved that number. That would be my number to set the jump.

Since each round is measured from the case base to ogive or at least the same point on the ogive, the bullets should all have the same jump.

 

[RonR]

What is your case neck thickness? 0.254" seems rather large unless your case necks are 0.014" or larger.

My bad, that was a typo. It should have been 0.245 instead of 0.254.

 

[supercorndogs]

First, Thanks to all for the help. Didn't mean to disappear on you, got tied up.

Here's what I meant by COAL. I used a Hornady Lock N Load O.A.L. Gauge to find the seating depth with the bullet I was using. After finding where the bullet touches the lands, I measured the length from case base to bullet tip. I then removed the bullet from the gauge and placed it in a sized case. I seated it until it was exactly the same length case base to bullet tip. I then used a Hornady headspace gauge to measure the case base to ogive and saved that number. That would be my number to set the jump.

Since each round is measured from the case base to ogive or at least the same point on the ogive, the bullets should all have the same jump.

You should have used a bullet comparator for that. The hornady headspace gauges are for measuring shoulder bump. I assume you are using the right things and saying the wrong things.

 

[RonR]

So you are having bullet creep? Btw, measure to ogive instead. Cause most bullet lengths will vary cause not all is same. Measuring OAL will give inconsistent readings because of this. Unless you sort and/or doing something to the Meplat. Weights of bullet will vary too. So sorting is recommended if your doing precision shooting at long distance.

Actually I measure to the ogive. Where I measured to the to the tip was so I could use that same bullet to set up a dummy reference round to the exact same over all length. Then I measured that dummy reference to the ogive and that becomes my reference.

At the time, I didn't realize I could measure base to ogive directly on the Hornady O.A.L. Gauge.

 

[RonR]

load 1 round at increasing charge weights by .2 to .3 grains until you get to 10 rounds. Last one should be your max load. Shoot using the lab radar and look for a flat spot. Pick the charge in the middle of the flat spot, and load 5 or 10 to confirm.

View attachment 6908014

I increased in 0.1 gr increments for 20 rounds, here's what I got. Measured with LabRadar and Magnetospeed together:

Never seen anything like this???

 

[RonR]

You should have used a bullet comparator for that. The hornady headspace gauges are for measuring shoulder bump. I assume you are using the right things and saying the wrong things.

Here's what I used to determine where the ogive contacted the lands:

https://www.midwayusa.com/product/4...d-overall-length-gauge-automatic-lever-action

Then here's what I used to measure from the base to the ogive:

https://www.midwayusa.com/product/4...headspace-gauge-5-bushing-set-with-comparator

 

[RonR]

...If your gun is pulling the bullets out of the case, you may be jammed into the rifling on some or all of your rounds.

I had a bullet seated long in a sized case with no primer or powder. I hand loaded it into the chamber and closed the bolt hoping that the bullet would be forced into the lands and hence back in the case. When I tried this, rather than extract the dummy round, the case extracted without the bullet.

Haven't had any live rounds seated into the lands (yet).

 

[MarinePMI]

Try splitting a case mouth vertically with a jeweler's saw. This will allow the bullet to be pushed into the case, when it is chambered. That should give you absolute max length. This is how it used to be done, before the Hornady Comparator was available....

 

[mdmp5]

Try splitting a case mouth vertically with a jeweler's saw. This will allow the bullet to be pushed into the case, when it is chambered. That should give you absolute max length. This is how it used to be done, before the Hornady Comparator was available....

Sometimes this kills all of the neck tension, and the bullet won't sit still. What I do is try to size a neck to about zero neck tension and close the bolt on it. Give your chamber and throat a quick patch beforehand

 

[supercorndogs]

Here's what I used to determine where the ogive contacted the lands:

https://www.midwayusa.com/product/4...d-overall-length-gauge-automatic-lever-action

Then here's what I used to measure from the base to the ogive:

https://www.midwayusa.com/product/4...headspace-gauge-5-bushing-set-with-comparator

This is what you should be using.

https://www.midwayusa.com/product/2...ad-bullet-comparator-basic-set-with-6-inserts

Headspace gauges are to measure shoulder bump during the sizing process.

 

[RonR]

This is what you should be using.

https://www.midwayusa.com/product/2...ad-bullet-comparator-basic-set-with-6-inserts

Headspace gauges are to measure shoulder bump during the sizing process.

Oops, sorry, I got in a hurry, that is what I'm using, and a RCBS micro case and bullet something or other:

 

[TxSteel]

I increased in 0.1 gr increments for 20 rounds, here's what I got. Measured with LabRadar and Magnetospeed together:

Never seen anything like this???

23.7 to 24.0 looks promising to me, if you aren't seeing any pressure. Personally i would load 10 rounds up at 23.9 and see what you get.

 

[RonR]

23.7 to 24.0 looks promising to me, if you aren't seeing any pressure. Personally i would load 10 rounds up at 23.9 and see what you get.

Thanks TxSteel, but should the velocity curve look like that??? How could the velocity go up and down with an ever increasing charge???

 

[TxSteel]

Thanks TxSteel, but should the velocity curve look like that??? How could the velocity go up and down with an ever increasing charge???

I would have to steer you to this video from the 6.5 Guys before I start lying to you. This is where I got the 10 round load development from.

 

[RonR]

I would have to steer you to this video from the 6.5 Guys before I start lying to you. This is where I got the 10 round load development from.

Great minds think alike! That's where I got the idea to do 0.1 gr increments thinking it would profile the barrel better with half the step size and twice as many bullets.

I'm gonna watch that again.