Lets start by saying I am an experienced reloader with over 50 years experience. I have come across something I can't explain. I am loading for a Savage 112 single shot bolt action 338 Lapua. Firing factory Hornady match and also Herters ammunition in rifle everything is fine. Attempted to neck size only and Savage brass can not be chambered no matter what setting on die. Herters neck sizes easily and chambers. I measured everything I could think of and can find no difference. All the Hornady I must full length size and it chambers as easily as the neck sized Herters. Any ideas?
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338 Lapua sizing issue
- Thread starter Ordsgt
- Start date
I measured everything except base to neck. I did measure from base to start of shoulder and it appears the same. Not sure how accurate as I am using dial caliper and start of shoulder may be + or-. I will have to shoot some more as all brass has been sized. Then I will check measurements again
That’s not how you measure shoulder length. Take a fired pistol case and put it over the case neck to touch the shoulder, then measure the difference.
It’s a very useful tool. Measuring the shoulder and only bumping it back 0.001”-0.002” is a very important part of reloading for me. This helps to ensure the case will fit in your chamber and doesn’t work the brass too much in case your bumping the shoulder too much. Bumping the shoulder a minimal amount also helps to avoid case head separations. When the brass expands in the chamber, the back end of the case is supported by the bolt so it can only expand forward into the chamber. The farther it expands forward the more it stretches the case and weakens the section near the head or web.
I know this doesn’t help you if you only want to size the neck.
I follow a different logic. The minimal shoulder bump you mention is extremely important but , I believe, for a different reason. When a resized case is chambered the front is supported because the ejector pushes the round forward until the chamber stops the shoulder. Any gap due to a "bump" dimension is at the rear of the case between the casehead and boltface. When fired, gas pressure obturates the brass and seals it to the chamber walls. The stretch can't go forward since the shoulder is in contact with the chamber. The case body is sealed to the chamber walls so that portion of the case is relatively fixed. The stretch goes toward the boltface gap and is concentrated in the very short section of the case behind the supporting chamber wall and forward of the web.
When loading for the range I neck size but only bump when the pressure needed to cam over the bolt during chambering becomes stiff. And then I only bump enough to reduce the pressure to an amount I find acceptable for my rifles. If I have done the steps correctly the shoulder is tight and the case has pushed the ejector back so the casehead is supported on the boltface.
Loading for hunting or other purposes is different. I increase the "bump" to guarantee chambering in field conditions.
When loading new cases there is an extra step. Some new brass can be quite short, especially .338LM. I'm sure you have seen this as well. I have found some at .007". That is a lot of stretch to force into the short unsupported portion of case just forward of the web. Initial stretch must go forward where it is distributed over a longer portion of the case. If not, the case, just forward of the web, will be strained and permanently weakened. My new cases get slightly squeezed with a set of padded pliers so that the upper body, just below the shoulder, is slightly out of round. On the first firing the bolt needs to force the case into the chamber with enough drag to overpower the ejector spring so that the casehead is in firm contact with the boltface. When fired the case becomes formed to that chamber. I only do this on the first firing of a new case.
I'm sure others use different techniques.
Thank you,
MrSmith
When loading for the range I neck size but only bump when the pressure needed to cam over the bolt during chambering becomes stiff. And then I only bump enough to reduce the pressure to an amount I find acceptable for my rifles. If I have done the steps correctly the shoulder is tight and the case has pushed the ejector back so the casehead is supported on the boltface.
Loading for hunting or other purposes is different. I increase the "bump" to guarantee chambering in field conditions.
When loading new cases there is an extra step. Some new brass can be quite short, especially .338LM. I'm sure you have seen this as well. I have found some at .007". That is a lot of stretch to force into the short unsupported portion of case just forward of the web. Initial stretch must go forward where it is distributed over a longer portion of the case. If not, the case, just forward of the web, will be strained and permanently weakened. My new cases get slightly squeezed with a set of padded pliers so that the upper body, just below the shoulder, is slightly out of round. On the first firing the bolt needs to force the case into the chamber with enough drag to overpower the ejector spring so that the casehead is in firm contact with the boltface. When fired the case becomes formed to that chamber. I only do this on the first firing of a new case.
I'm sure others use different techniques.
Thank you,
MrSmith
I understand what you are saying. My 6.5 creednore and 7.62 rifles have outstanding accuracy with no issues on brass. Now the Lapua is new territory for me. I got it to participate in a mile match but am experiencing the brass issue that I have never had before. On an unrelated matter. I have never seen such disparity in load manuals. What one manual calls for as a minimal load another has it as a max load. So far the Lyman 50th edition appears to be accurate based on my chronograph and pressure signs. Load is Hornady 285 ELD match with 88 gr Retumbo velocity 2692 avg
I can see your point of view or direction. You could be very correct as well since many ejector springs are very stiff and would push the round forward.
Absolutely correct. A very valid concern. I should have included this earlier as a pitfall of pushing the headspace past zero.
Thank you,
MrSmith
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Savage 338LM chambers tend to run on the tight side. I have helped a few buddies out with similar issues. Bolt sticking at the top or "clickers" as some guys call them, are quite common if you do not full length bump size every time. A comparator like Jugerxxx suggested is indispensable for establishing proper shoulder bump. If you are loading near the top end for 338LM loads and you have a tight chamber, I doubt you will ever be able to just neck size your 338 brass. Its also very easy to overpressure 338 brass and everything look okay with your rifle but you could be straining the receiver with a savage or Remington based action so be careful. See thread below
http://www.snipershide.com/shooting/threads/338-lapua-and-lug-sheer.53600/
http://www.snipershide.com/shooting/threads/338-lapua-and-lug-sheer.53600/
I had the same problem with my savage 112. I ended up getting a redding body die to bump the sholder back 2thou after neck sizing. Everything feeds smoothly now. Also as others mentioned get yourself a headspace gauge. It is very useful
Got headspace gauge and this is the measurements
case - Measurement - Chamber ?
Factory Hornady - 2.348 - Yes
Hornady fired case - 2.348 - Yes-stiff
Herter Neck Size - 2.348 - Yes
Hornady neck size - 2.348 - No
Hornady FL size - 2.344 - Yes
What am I missing? Makes no sense too me.
Factory bolt lift good all reloads stiffer with more resistance at end. Possible pressure issue? Everything as per Lyman manual and velocity at or below
the published and my barrel is 26 inch theirs 24 inch. Loads are 1 to 2 grains below Lyman. 5 grains under Hornady max
case - Measurement - Chamber ?
Factory Hornady - 2.348 - Yes
Hornady fired case - 2.348 - Yes-stiff
Herter Neck Size - 2.348 - Yes
Hornady neck size - 2.348 - No
Hornady FL size - 2.344 - Yes
What am I missing? Makes no sense too me.
Factory bolt lift good all reloads stiffer with more resistance at end. Possible pressure issue? Everything as per Lyman manual and velocity at or below
the published and my barrel is 26 inch theirs 24 inch. Loads are 1 to 2 grains below Lyman. 5 grains under Hornady max
Are you using a true neck die or a bushing FL sizing die? If you are using a true neck only die I would suggest that you take the ID and OD measurements of the herters and hornady brass and compare. The hornady brass may not be getting sized enough in the neck. I suspect that the herters has a slightly smaller od in the neck or has thicker case web than the hornady and is able to go 1 firing without needing to be FL sized as a possibility as well. Take a second OD measurement about .3" above the web of each brass type.
Coated 3 shells with graphite and chambered them 1st shell hornady neck size, 2nd Hornady FL size, 3rd Herters neck size. Am using a separate neck size die set the same for both Hornady and Herters. Hornady case had to be pushed out with cleaning rod.. On the full legth size case I did not have graphite on the very bottom of the shell
m.
It looks to me that your Hornady brass is softer and needs to be FL sized everytime.
Peterson is worth a shot, for sure. Good to see you worked through the problem. With each new brass/chamber combination, I do a little extra work in the beginning to get to know how they work together. I do a range of measurements with unfired brass, then fired, to see where the movement occurs and how much. I have the Hornady headspace gauge, but like the ease of use and excellent reproducibility of the Whidden Case Gauge:
https://www.whiddengunworks.com/product/case-gauge-3/
I'd like some hotshot engineer to make a little interferometer that you can put a case into and get accurate 3-D measurements of the entire case.
(not holding my breath and probably couldn't afford it anyway)
