Finding the lands

[Dildobaggins]

So last night I tried using a method after watching a video by erik Cortina. Where you wax the inside of the bullet and send the bolt home slowly. Then open it fast. I measured before and after. (This is for a 6 creed) When I did this I was definitely hitting the lands. I measured before and after. And got the same measurement. My neck tension on the cases I was using was .240, so I think that might have been a problem? But I tried like 5 times and was getting measurements all over the place.

Questions

Has anyone ever used a fired case with loctite to find the threads? Ultimate reloader showed a video on how to do it, but red loctite? I can't imagine that would be fun if it got into the chamber.

Other than an OAL guage does anyone else have a simple method?

Thanks fellas

 

[nn8734]

Cut two or three small slits in the case neck and fit the bullet in just enough so it stays in place then insert it into the action and close the bolt. Carefully, slowly open the bolt and retrieve the round and take your measurements.

Its a crude method that takes some time to get a decently reliable measurement but costs nothing.

Ive done this a bunch of times years ago before simply spending the money for the Hornady oal gauge.

Unless you’re working with vld bullets (secant ogive) you can start with replicating factory match ammo oal, that is a sufficient starting point while you wait for your gauge to arrive.

 

[hafejd30]

Just get the Hornady OAL gauge. It’s cheap compared to the pain in the ass old school methods. Works very well and you can drill/tap your once fired cases if you can’t find a Hornady one in stock

Otherwise I used to cut relief grooves in the neck. Squeeze it slightly to create tension. Then sharpie the bullet to see that it made contact with the lands. But this measurement would be all over the place and take many times to confirm OAL

 

[Dildobaggins]

Cut two or three small slits in the case neck and fit the bullet in just enough so it stays in place then insert it into the action and close the bolt. Carefully, slowly open the bolt and retrieve the round and take your measurements.

Its a crude method that takes some time to get a decently reliable measurement but costs nothing.

Ive done this a bunch of times years ago before simply spending the money for the Hornady oal gauge.

Unless you’re working with vld bullets (secant ogive) you can start with replicating factory match ammo oal, that is a sufficient starting point while you wait for your gauge to arrive.

Great idea! Thank you.

 

[nn8734]

Great idea! Thank you.

You’re welcome.

As an aside (and you probably already know this but in case not) the Hornady gauge serves a more important purpose in that it enables you to measure case head-to-shoulder datum length which is needed for proper f/l sizing die set up so you can achive proper shoulder bump.

That is more crucial than knowing ogive jam length unless you’re working with either vld bullets, a wildcat chambering (or both).

 

[Dildobaggins]

You’re welcome.

As an aside (and you probably already know this but in case not) the Hornady gauge serves a more important purpose in that it enables you to measure case head-to-shoulder datum length which is needed for proper f/l sizing die set up so you can achive proper shoulder bump.

That is more important than knowing ogive jam length unless you’re working with either vld bullets, a wildcat chambering (or both).

I did not know this. I'm new to reloading. Been loading for my AR 223 with stellar results, but trying to squeeze all the accuracy out of this 6 creed. I've been looking all over this forum for months and I don't even feel like I've scratched the surface/ no idea what I'm doing. Haha

 

[hafejd30]

You’re welcome.

As an aside (and you probably already know this but in case not) the Hornady gauge serves a more important purpose in that it enables you to measure case head-to-shoulder datum length which is needed for proper f/l sizing die set up so you can achive proper shoulder bump.

That is more crucial than knowing ogive jam length unless you’re working with either vld bullets, a wildcat chambering (or both).

Good advice ^

 

[nn8734]

I did not know this. I'm new to reloading. Been loading for my AR 223 with stellar results, but trying to squeeze all the accuracy out of this 6 creed. I've been looking all over this forum for months and I don't even feel like I've scratched the surface/ no idea what I'm doing. Haha

Gotcha. New reloaders today have the opposite problem as those 25 years ago in that now it probably feels like you’re drinking from a firehose with all the available info whereas back then you were drinking from a trickle.

To me, reloading is like anything else in that at a high level I only really manage to three things:

Cost, Risk and Performance.

Keep your requirements crisp based on how you plan to employ the rifle then balance the above three when deciding how deep into the rabbit hole you want to go.

Here’s my load RTDE approach in a nutshell when im reloading a cartridge im not already familiar with, loading-wise:

Step	What I'm Doing	What I'm Looking For	Notes
1	Initial OCW 3-5 shots per group	POI Consistency from Chg Weight to Chg Weight, MV and Pressure Signs	MV Data: Im only looking at MV (not SD or ES) to see what charge weights my min required MV is met and if pressure is present at that MV where POI is consistent from increment to increment
2	Refined OCW 10-15 shots per group, adjacent CWs	POI consistency (repeated from initial OCW), group size at 100m and at 600m	If group size is not to my liking but MV and POI consistency is there, I go to seating depth testing in an additional session before going to step 3
3	Final validation - 40-60 rounds	MV Consistency (SD/ES), group size, elevation hold overs at various KDs vs predicted (either via FDAC or ballistic app), overall performance impressions	If SD/ES are reasonable (low double digits, high single digits across 40 rounds im good - i put the load into production. If it all comes apart, i diagnose and re-group (honestly, this very rarely happens)

The ocw method is one of a few popular ones and has worked well for me. Id avoid saterlee style tests unless simply testing to find your rifle’s pressure threadshold with a given set of components.

Lastly, pick up a good reloading manual - it will lay out the basics to help you get started. There’s also a couple sticky threads dedicated to helping new reloaders get off the ground.

 

[hafejd30]

I find with my guns,

Berger vld 180 in my fclass 284 like .015” jump
Hornady anything likes .020”-.030”
Sierra matching .015” in my 260

Just for reference

 

[straightshooter1]

I find with my guns,

Berger vld 180 in my fclass 284 like .015” jump
Hornady anything likes .020”-.030”
Sierra matching .015” in my 260

Just for reference

What are the COAL's for those jumps?

Since different guns can have substantially different sized chambers, that jump really doesn't tell us anything about your seating depth, like, how it might related to my particular chamber. Knowing the COAL, I can better determine better how those cartridges with those jumps relate to my chambers.

 

[hafejd30]

What are the COAL's for those jumps?

Since different guns can have substantially different sized chambers, that jump really doesn't tell us anything about your seating depth, like, how it might related to my particular chamber. Knowing the COAL, I can better determine better how those cartridges with those jumps relate to my chambers.

I guess I’m not following what your asking. This measurement is how far from the lands my ogive is on my particular chamber/throat. Just an observation I’ve noticed on what certain bullets seem to prefer. Some like some jump, some like none, some don’t care. My OAL measurement may not necessarily be what your gun prefers….

 

[CK1.0]

Cortina shares some great tricks... his "jam method" for finding the lands isn't one of them (IMO).

Here, Deep Creek Method:

 

[straightshooter1]

I guess I’m not following what your asking. This measurement is how far from the lands my ogive is on my particular chamber/throat. Just an observation I’ve noticed on what certain bullets seem to prefer. Some like some jump, some like none, some don’t care. My OAL measurement may not necessarily be what your gun prefers….

True, your COAL may not be what my gun prefers . . . because it's the seating depth (how far the base of the bullet is from the base of the case for a particular amount of case capacity) that's the important issue. That's why seating depth testing is so important to get a load tuned.

You tell me your 180's with .015" jump works for you. But in my chamber, your .015" jump might represent a .045" jump, which means the seating depth is way different if I were to do a .015" jump. If I know your COAL, I can figure out that seating depth and how much jump that represents in my chamber.

 

[hafejd30]

True, your COAL may not be what my gun prefers . . . because it's the seating depth (how far the base of the bullet is from the base of the case for a particular amount of case capacity) that's the important issue. That's why seating depth testing is so important to get a load tuned.

You tell me your 180's with .015" jump for you works for you. But in my chamber, your .015" jump might represent a .045" jump, which means the seating depth is way different if I were to do a .015" jump. If I know your COAL, I can figure out that seating depth and how much jump that represents in my chamber.

I got ya

I’ll try to get measurements tomorrow. I sort the bullets so I have both base to ogive of the bullet as well as base to ogive of the loaded round. But keep in mind that’s only good info if your running the same bullet with similar OAL

Truthfully I want to start sorting by bearing surface. Just haven’t got the second comparator yet

 

[Dildobaggins]

Gotcha. New reloaders today have the opposite problem as those 25 years ago in that now it probably feels like you’re drinking from a firehose with all the available info whereas back then you were drinking from a trickle.

To me, reloading is like anything else in that at a high level I only really manage to three things:

Cost, Risk and Performance.

Keep your requirements crisp based on how you plan to employ the rifle then balance the above three when deciding how deep into the rabbit hole you want to go.

Here’s my load RTDE approach in a nutshell when im reloading a cartridge im not already familiar with, loading-wise:

Step	What I'm Doing	What I'm Looking For	Notes
1	Initial OCW 3-5 shots per group	POI Consistency from Chg Weight to Chg Weight, MV and Pressure Signs	MV Data: Im only looking at MV (not SD or ES) to see what charge weights my min required MV is met and if pressure is present at that MV where POI is consistent from increment to increment
2	Refined OCW 10-15 shots per group, adjacent CWs	POI consistency (repeated from initial OCW), group size at 100m and at 600m	If group size is not to my liking but MV and POI consistency is there, I go to seating depth testing in an additional session before going to step 3
3	Final validation - 40-60 rounds	MV Consistency (SD/ES), group size, elevation hold overs at various KDs vs predicted (either via FDAC or ballistic app), overall performance impressions	If SD/ES are reasonable (low double digits, high single digits across 40 rounds im good - i put the load into production. If it all comes apart, i diagnose and re-group (honestly, this very rarely happens)

The ocw method is one of a few popular ones and has worked well for me. Id avoid saterlee style tests unless simply testing to find your rifle’s pressure threadshold with a given set of components.

Lastly, pick up a good reloading manual - it will lay out the basics to help you get started. There’s also a couple sticky threads dedicated to helping new reloaders get off the ground.

All good info man. Much appreciated. I have Lyman and Hornady reloading Manuel's. I remember when I got the Lyman it had some good info in it and life happened and I didn't read much further. I'll look alot more into the method you posted and continue to read Lyman's information. Glad I asked this question.

 

[SONIC SAAMI]

are you trying with the objector in the bolt?

 

[Dildobaggins]

are you trying with the objector in the bolt?

Yeah, I'm guessing I should remove that?

 

[SONIC SAAMI]

LOL…
And you might wanna try hooking the case over the extractor rather than the extractor jumping over the head of the case.

But I tell you what true one day about 25 years ago I sat down with a bottle of bourbon and meditated all this horseshit away and just started loading and shooting

 

[Dildobaggins]

LOL…
And you might wanna try hooking the case over the extractor rather than the extractor jumping over the head of the case.

But I tell you what true one day about 25 years ago I sat down with a bottle of bourbon and meditated all this horseshit away and just started loading and shooting

I'm an idiot. I hear you. I wish all this was simple for me, but last month I shot the smallest group of my life, and it almost made all of it worth it haha

 

[SONIC SAAMI]

You’ll be all right give yourself some time and about 10,000 rounds/5 barrels shooting the same cartridge.

 

[918v]

Cut two or three small slits in the case neck and fit the bullet in just enough so it stays in place then insert it into the action and close the bolt. Carefully, slowly open the bolt and retrieve the round and take your measurements.

Its a crude method that takes some time to get a decently reliable measurement but costs nothing.

Ive done this a bunch of times years ago before simply spending the money for the Hornady oal gauge.

Unless you’re working with vld bullets (secant ogive) you can start with replicating factory match ammo oal, that is a sufficient starting point while you wait for your gauge to arrive.

One slit is plenty

 

[straightshooter1]

I got ya

I’ll try to get measurements tomorrow. I sort the bullets so I have both base to ogive of the bullet as well as base to ogive of the loaded round. But keep in mind that’s only good info if your running the same bullet with similar OAL

Truthfully I want to start sorting by bearing surface. Just haven’t got the second comparator yet

Am looking forward to those measurements. And yeah, I understand about the issues for the same bullet, like differences in oal's.

I've sorted by bearing surface once and with one 500 count box, I found some with ES of .033". So, I ran a test to see what that difference might make and fired 20 rounds on each end of that ES. I found a definite difference in POI's and average MV's. This was with some Sierra bullets and typically, I haven't see that much difference again and seldom enough difference to make a difference on paper. So, unless I see a significant difference in bearing surface, I don't pay any attention to it.

These days, I sort my bullets from base to the seating stem contact point on the ogive. I do this because that give me a very consistent seating depth, which is my goal. Though the seating depths are very consistent, the standard BTO measurement varies. That BTO variance isn't important to me since the amount of jump has very little significance compared to seating depths. After all, the jump will increase over time as the throat erodes and keeping the same seating depth maintains the accuracy for quite a while for the non VLD bullets I've used. VLD's tend, in my experience, to need a little adjustment in seating depths after a while as the throat erodes.

 

[918v]

Don’t do anything to the bolt. Remove the bolt from the action. Size a case to achieve zero clearance. Cut one slit through the neck into the shoulder. Debur the slit. Seat a bullet long into the neck. Press the round into the chamber so the shoulder of the case bottoms out. The lands will push the bullet into the neck. Use a cleaning rod to push the round out of the chamber. You’ll feel the bullet wedged itself in the lands. That’s ok, just gently push it out. Measure the round.

 

[918v]

So last night I tried using a method after watching a video by erik Cortina. Where you wax the inside of the bullet and send the bolt home slowly. Then open it fast. I measured before and after. (This is for a 6 creed) When I did this I was definitely hitting the lands. I measured before and after. And got the same measurement.

What you did caused the bullet to get stuck in the rifling and when you extracted the bullet pulled out of the neck. Highly inaccurate way of finding the lands.

 

[Dildobaggins]

What you did caused the bullet to get stuck in the rifling and when you extracted the bullet pulled out of the neck. Highly inaccurate way of finding the lands.

Thats what I figured was happening. I'm going to keep looking but I think I'm either going to make some cuts in a case like mentioned here or try the loctite method.

 

[918v]

Thats what I figured was happening. I'm going to keep looking but I think I'm either going to make some cuts in a case like mentioned here or try the loctite method.

The bullet will always get stuck in the rifling, even slightly. That’s why pushing it out with a cleaning rod from the opposite end is better because it dislodges the stuck bullet without changing its position in the neck.

 

[straightshooter1]

Thats what I figured was happening. I'm going to keep looking but I think I'm either going to make some cuts in a case like mentioned here or try the loctite method.

Below is a pic of my .308 fired case that I cut two slots in to find the lands. The bullets is in just tight enough to slide when I close the bolt and not stick in the lands when I pull it out. It took some practice to get the feel for it where this method has worked pretty well in getting consistent measurements for me (like within +/- .0015").

 

[Dildobaggins]

Below is a pic of my .308 fired case that I cut two slots in to find the lands. The bullets is in just tight enough to slide with I close the bolt and not stick in the lands with I pull it out. It took some practice to get the feel for it where this method has worked pretty well in getting consistent measurements for me (like within +/- .0015").

View attachment 7936428

What did you cut the neck with? I was thinking maybe a Dremel. With a cutting wheel.

 

[straightshooter1]

What did you cut the neck with? I was thinking maybe a Dremel. With a cutting wheel.

That's exactly what I used.

 

[Haney]

So last night I tried using a method after watching a video by erik Cortina. Where you wax the inside of the bullet and send the bolt home slowly. Then open it fast. I measured before and after. (This is for a 6 creed) When I did this I was definitely hitting the lands. I measured before and after. And got the same measurement. My neck tension on the cases I was using was .240, so I think that might have been a problem? But I tried like 5 times and was getting measurements all over the place.

Questions

Has anyone ever used a fired case with loctite to find the threads? Ultimate reloader showed a video on how to do it, but red loctite? I can't imagine that would be fun if it got into the chamber.

Other than an OAL guage does anyone else have a simple method?

Thanks fellas

I use a stripped bolt , easy, accurate, and repeatable . Repeatable is key to knowing exactly where those lands are , erik cortina is a douche with a big mouth , I would avoid anything that idiot has to offer . The reason your measurements were all over the map was because his method is a joke .

 

[CK1.0]

Shit-show alert, these "slit case methods" being discussed are a bunch of dogshit... inaccurate and not reliably repeatable.

Also, COAL is an almost useless measurement unless rounds won't fit in your magazine and you need to figure out how much shorter they have to be, that's about it, please stop.

Don't waste your money on the stupid/useless Hornady modified-case/chamber-measurement tool. Buy a comparator tool instead, so you can reliably measure base-to-ogive (BTO/CBTO), and base-to-shoulder, measurements that you can/will actually use.

The Deep Creek Method is 100% reliable and repeatable and doesn't require or rely on any special tool or apparatus to deliver a trustworthy measurement. Pull the firing pin assembly from your bolt, if it's controlled-round-feed using a mechanical ejector (like an Origin), then that's it, you're ready, if it's traditional Rem700 style, with a spring-loaded ejector, then you'll need to temporarily strip that too. Now look up the Deep Creek Method on Youtube and follow the directions, remember to slip the case rim under the extractor hook (or be mindful that it pops under the hook) before the dummy round goes all the way into the chamber. When there is no more "click" upon extraction, you'll have a dummy round that's exactly at the lands, and then you can record that measurement using your comparator tool for your notes.

 

[Schütze]

I use a stripped bolt , easy, accurate, and repeatable . Repeatable is key to knowing exactly where those lands are , erik cortina is a douche with a big mouth , I would avoid anything that idiot has to offer . The reason your measurements were all over the map was because his method is a joke .

And wtf are you?

I would avoid ANYTHING you have to „offer“

 

[Dildobaggins]

I don't think Cortina's method is new, or maybe he modified it? In the ultimate reloader video I watched Eric's method and the loctite method. They both gave almost identical results. The Hornady gauge was the one that gave an off measurement for jam point

 

[Govt Mule]

The Deep Creek Method is 100% reliable and repeatable and doesn't require or rely on any special tool or apparatus to deliver a trustworthy measurement. Pull the firing pin assembly from your bolt, if it's controlled-round-feed using a mechanical ejector (like an Origin), then that's it, you're ready, if it's traditional Rem700 style, with a spring-loaded ejector, then you'll need to temporarily strip that too. Now look up the Deep Creek Method on Youtube and follow the directions, remember to slip the case rim under the extractor hook (or be mindful that it pops under the hook) before the dummy round goes all the way into the chamber. When there is no more "click" upon extraction, you'll have a dummy round that's exactly at the lands, and then you can record that measurement using your comparator tool for your notes.

The Alex Wheeler method is the most reliable method I have found for single shot actions in my competition rifles (BR and F-class). I used the Hornady OAL gauge for years with great results on my varmint rifles that were magazine fed. Rather than cutting slots with a Dremel, use a dowl with wet/dry sand paper wrapped around it to open up the inside of the neck to get a slight friction fit with the Hornady gauge. The 6CM is probably available in a tapped cartridge by now, so you won't have to do your own.

The lands/throat area is a constant moving target if you shoot much at all. It is nice to have a baseline measurement to start with, but you want to find that jump into the lands that gives you the largest/longest node for accuracy without changing your seating depth. I have barrel/bullet combinations that never have to be changed for the life of the barrel, and some that I have to adjust the seating depth every couple hundred rounds.

 

[hafejd30]

HORNADY LOCK-N-LOAD BULLET COMPARATOR BASIC SET | Brownells

Measuring cartridge lengths across the bullet tips is not a reliable (or repeatable) method for measuring loaded rounds. Its common for variations of up to .025" to exist from one round to the next. Hornady's Bullet Comparator measures rounds from...

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Hornady Lock-N-Load C-1000 Straight O.A.L. Gauge

Accurately measure seating depth with the Hornady Lock-N-Load C-1000 Straight O.A.L. Gauge. This gauge is designed for caliber specific Hornady Modified Cases.

www.midsouthshooterssupply.com

 

[918v]

Shit-show alert, these "slit case methods" being discussed are a bunch of dogshit... inaccurate and not reliably repeatable.

Also, COAL is an almost useless measurement unless rounds won't fit in your magazine and you need to figure out how much shorter they have to be, that's about it, please stop.

Don't waste your money on the stupid/useless Hornady modified-case/chamber-measurement tool. Buy a comparator tool instead, so you can reliably measure base-to-ogive (BTO/CBTO), and base-to-shoulder, measurements that you can/will actually use.

The Deep Creek Method is 100% reliable and repeatable and doesn't require or rely on any special tool or apparatus to deliver a trustworthy measurement. Pull the firing pin assembly from your bolt, if it's controlled-round-feed using a mechanical ejector (like an Origin), then that's it, you're ready, if it's traditional Rem700 style, with a spring-loaded ejector, then you'll need to temporarily strip that too. Now look up the Deep Creek Method on Youtube and follow the directions, remember to slip the case rim under the extractor hook (or be mindful that it pops under the hook) before the dummy round goes all the way into the chamber. When there is no more "click" upon extraction, you'll have a dummy round that's exactly at the lands, and then you can record that measurement using your comparator tool for your notes.

You are incorrect

 

[huntnh]

Get the gauge worth every penny I use mine all the time especially if you loading for several different rifles and bullet combos.

 

[CK1.0]

You are incorrect

How? Explain?

Tell us how using a unicorn-case and a bullet seated with a questionable press-fit that you have to hope doesn’t get bumped or moved in any way as it’s extracted… somehow yields a precise, repeatable measurement?

(Actually sounds even more retarded after typing that…)

 

[Fred @ Bison Tactical]

I have struggled with the same question. I have the hornady guage and I have to average the measurements because they are so inconsistent. I don't really like that about the gauge. I have seen I believe Erik Cortina's old method, which I like - which is remove the barrel and drop a round into the chamber, when it pops free with very little force using a fingernail, its free of the lands.

That being said I used to use the Wheeler method, which is similiar/same as the Deep Creek method. The problem even though Deep Creek says it doesn't rely on feel, is that is relys on a lot of feel, and you have to remove the extractor along with the firing pin assembly. If you don't remove the extractor it messes with the feel, and you wont get it right.

I like Erik Cortinas method with the drop best after trying a lot.

 

[straightshooter1]

Shit-show alert, these "slit case methods" being discussed are a bunch of dogshit... inaccurate and not reliably repeatable.

Also, COAL is an almost useless measurement unless rounds won't fit in your magazine and you need to figure out how much shorter they have to be, that's about it, please stop.

Don't waste your money on the stupid/useless Hornady modified-case/chamber-measurement tool. Buy a comparator tool instead, so you can reliably measure base-to-ogive (BTO/CBTO), and base-to-shoulder, measurements that you can/will actually use.

The Deep Creek Method is 100% reliable and repeatable and doesn't require or rely on any special tool or apparatus to deliver a trustworthy measurement. Pull the firing pin assembly from your bolt, if it's controlled-round-feed using a mechanical ejector (like an Origin), then that's it, you're ready, if it's traditional Rem700 style, with a spring-loaded ejector, then you'll need to temporarily strip that too. Now look up the Deep Creek Method on Youtube and follow the directions, remember to slip the case rim under the extractor hook (or be mindful that it pops under the hook) before the dummy round goes all the way into the chamber. When there is no more "click" upon extraction, you'll have a dummy round that's exactly at the lands, and then you can record that measurement using your comparator tool for your notes.

If one is loading to jump their bullets, say .020, .040, or .060", how accurate does one need to be for finding where the lands is?

 

[Govt Mule]

If one is loading to jump their bullets, say .020, .040, or .060", how accurate does one need to be for finding where the lands is?

That is why I said the best scenario is to find the jump that will keep the "tune" the longest without having to adjust the seating. I have throats that move .002 in a day. I would be fucked if I needed to adjust seating depth half way through a match.

If you are using a Hornady gauge with a fire formed case from your chamber (not a modified case from Hornady), you can be really consistent with your measurements. Even with the Wheeler method or the old Cortina method you can get readings that vary if the base to ogive is different in the bullets measured.

 

[spife7980]

If one is loading to jump their bullets, say .020, .040, or .060", how accurate does one need to be for finding where the lands is?

That depends on your bullet and chamber relationship and how effected by the change in depth the results are. Tangent ogive, not at all, secant its much more necessary.

But rather than arbitrarily saying how far off you are you should instead be testing what works best and let that testing dictate your actions.
Which is really what my understanding of the cortina seating depth method is. Ballparkish initial number so you arent jammed and then see what works best from there, the actual number off to the thousandth becomes inconsequential if you find what works.

 

[nn8734]

If one is loading to jump their bullets, say .020, .040, or .060", how accurate does one need to be for finding where the lands is?

Yep, this was the point I made in the first reply to the OP’s questions: unless you working with VLD bullets w/a secant ogive, its not going to matter…

I start with factory match ammo cbto and adjust from there if/as needed….people are pouring too much time into nailing down jump when using tangent or hybrid bullets and it’s totally unnecessary.

Example: Ive jumped 169 smks anywhere from .030 to .150” across multiple 308 rifles and they all shot tight and to expectations. What little variance i was getting with the Hornady tool when measuring for jam was inconsequential when it came to results on target.

The above applies when using Sierra Matchkings or Berger Hybrids across all my bolt rifles. For semis, you’re limited to mag length anyway most of the time so finding jam doesnt even matter.

 

[918v]

How? Explain?

Tell us how using a unicorn-case and a bullet seated with a questionable press-fit that you have to hope doesn’t get bumped or moved in any way as it’s extracted… somehow yields a precise, repeatable measurement?

(Actually sounds even more retarded after typing that…)

Read post number 23

 

[TCreedmoor]

I was lucky enough to find a Stoney Point OAL gauge at a gun show. I purchased the modified 6.5 Creedmoor case and measured multiple times using a Hornday 140 gr ELD-Match bullet. The readings were a consistent COAL of 2.847". Even if I was off by a few 1000ths of an inch, all you're trying to do is establish the starting point. Using Eric Cortina's process, you take the 'Lands' value and subtract 0.020" to define your starting point. Since everyone's comparator tool will read slightly different, I referenced all my measurements using the COAL with my 140 grain ELD-Match bullets. 2.847" - 0.020" = 2.827". I reference and label my cartridges using the COAL, but I'm actually measuring using a comparator on the Ogive. My longest cartridges were seated for a COAL of 2.827". Then down in 0.003" increments down to a COAL of 2.815". I've never tried making cartridges that are 2.830" or longer.

Hornady factory 140 gr ELD-Match ammo has a COAL of 2.800". I keep a master 2.847" dummy and a 2.800" factory cartridge by my reloading table. I zero out my comparator caliper using the factory 2.800" cartridge and measure every cartridge I reload. My caliper measurements are then 0.027" down to 0.015". I start reloading with the longest rounds so if I overshoot the bullet seating, I just save that one for a deeper seating depth (shorter length). By the way, even the longest cartridges (2.827" COAL) feed just time from the AICS magazine on my bolt action precision rifle.

I've found the powder, grain weight and seating depth all play a factor in the group size. For IMR 4350, my tightest groups are a COAL of 2.824". For Winchester StaBall 6.5 it's a COAL of 2.818". For H4350 it's 2.821". To compute my actual bullet jump, subtract those COAL values from 2.847".

If you don't want to buy a OAL gauge, ask around at your rifle range. If someone asked me, I'd bring my OAL gauge on my next visit for them to take measurements. If they had a different caliber, I'd tell them to buy the modified case at Bass Pro, Cabela's or online. And, most importantly, for them to bring the bullet(s) they plan on reloading. The outdoor range I visit is a fixed price for the entire day, so spending 20-30 minutes helping someone get the measurements they need (or sight-in their scope) is just good Karma in my book. I have people who teach/mentor me on precision shooting and reloading, so I need to pass it on.

 

[Dildobaggins]

Perhaps I'll just buy the Hornady OAL guage. I'm heading to sportsman's warehouse later today anyway. I'll do that method, and then 1 other, and see how they compare. Can't hurt doing it more than 1 way I guess.

 

[Fred @ Bison Tactical]

If one is loading to jump their bullets, say .020, .040, or .060", how accurate does one need to be for finding where the lands is?

The problem is you need to know where to start, otherwise you won't know where you are? Say you subscribe to the idea that you have a wide node between .050 and .080 and you want to keep start at .050 so you don't have to mess with things for a while. How will you know your not at .030 instead of .050?

Alternatively you may have strange pressure signs and be concerned your actually touching lands or something - so how do you figure out where something is touching - this requires determining where the bullet isn't touching something causing issues or so you can start where you want to jump...

 

[straightshooter1]

The problem is you need to know where to start, otherwise you won't know where you are?

Absolutely, you need to know where to start by finding the touch point on the lands and decide about how far from the lands you want to be. Then the tuning process begins (though one might try various distances from the lands like Berger recommends to maybe get close to a node, beforehand.

Say you subscribe to the idea that you have a wide node between .050 and .080 and you want to keep start at .050 so you don't have to mess with things for a while. How will you know your not at .030 instead of .050?

Whether it's .030 or .050, does finding the lands within something like .005's really make a difference to start with?

Alternatively you may have strange pressure signs and be concerned your actually touching lands or something - so how do you figure out where something is touching - this requires determining where the bullet isn't touching something causing issues or so you can start where you want to jump...

If one is loading to touch, jam or be something less than .010 from the lands, then an accurate measurement would certainly be important and in such a case to maintain the consistent presure spike, one would have to continually get accurate measurement to main touch or jam as the throat erodes. Right?

 

[TCreedmoor]

Whether it's .030 or .050, does finding the lands within something like .005's really make a difference to start with?


If one is loading to touch, jam or be something less than .010 from the lands, then an accurate measurement would certainly be important and in such a case to maintain the consistent presure spike, one would have to continually get accurate measurement to main touch or jam as the throat erodes. Right?

You are completely correct. As long as you're not chasing a touch, jam or really short jump, then an accurate measurement is less critical. As I stated in my earlier post, I followed Eric Cortina's recommendation of starting 0.020" off the lands and working down in 0.003" increments. My nodes are 3, 6 or 9 thousandths deeper than 0.020" depending on the powder. (IMR 4350 vs StaBall 6.5 vs H4350)

It's not about the exact dimension off the lands, or the bullet jump dimension itself. It's about finding the seating depth (and COAL) gives you the tightest groups. With a caveat of being at least 0.020" off the lands -- though some people want to shrink that dimension slightly (ex. 0.015") Shooting multiple groups at different seating depths is what allows you to find the node.

I shoot a 5-shot group at each seating depth. At some point I'll probably make a few cartridges that would be 0.017" off the lands -- just in case my original measurement was off. As I type this I'm wondering if I should try some additional seating depths for smaller COALs such as 2.812", 2.809", 2.806" and 2.803". (Factory ammo is 2.800") I punch holes in paper every other weekend, so spending a little bit more time adjusting the seating depth for an evening is no big deal.

 

[hafejd30]

Whether it's .030 or .050, does finding the lands within something like .005's really make a difference to start with?

I know we discussed stuff in pm’s. But generally I like to start .020” off with any bullet I use. Usually I test a range of powder charges at .020” initially. Testing seating depth is my last step generally if I’m looking for top level of accuracy. Watching for pressures as I approach the lands and seeing what range jump the gun shoots best. Then maybe fine tune powder charge if needed