.308 brass - trim to length question...

Tonester

Tonester

New member
I have a question for those who reload for the .308 Winchester cartridge. I recently bought a .308 Savage Axis XP. I used some brass and noticed that it does not chamber. I started checking the trim length. Some brass cases were at 2.016/2.017. I expected that to happen with a chuck trimmer.

My reloading manuals show a max trim length of 2.015 and a minimum of 2.005. I looked at the SAAMI specs and they show 2.015 with a variation of .020. That means 1.995 to 2.015. After trimming some brass, my rifle likes cases trimmed at 2.000.

After talking with other reloaders, they did not seem to find an issue with the length. However, some online say there is potential for carbon build up when trimming the case at that length.

Does anyone else trim their .308 brass to 2.000?"

Any info/advice welcome.

TC
 
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I don't trim that short on purpose but wouldn't think it'd hurt bad. My guess is you don't have the size die screwed down far enough or you're using unsized brass fired out of a different rifle.
 
Unlikely that it is case length causing your issue. I would address shoulder height first and then worry about trimming. The Hornady HS tool is your friend or even a 9 MM case and a caliper. You want a shoulder bump around 0.004 for your cases. In the absence of the tool try screwing your sizer in 1/8 turn and trying a couple. Keep trying until they chamber without any hard bolt closing.

Greg

2.000 is fine though I stop at 2.005.
 
I suppose it is possible to find a factory rifle that has a chamber short of SAAMI specs, a chamber cast will give you a measurable item. Find a case that will not chamber(that measures close to 2.015) and adjust your die until it chambers with minimal bolt closing pressure, make sure the case is lubed well as it may take several die adjustments to reach the correct sizing amount. I do not use the decapping/expander rod when adjusting the sizing die(I decap with a decapping die for .224 and larger).
 
I have my trimmer set to 2.005. I'll let it get up to 2.010 and i'll trim again. Has been fine in my Savage 11 action.

Are you bumping the shoulder enough in the sizing die?
 
Thank you for the input! Now I have some work to do. I will experiment by turning in the die 1/8 until the case chambers.
 
Rather than go through the gymnastics of the chamber casting pick up one of these in 308 and you will have a definitive answer quickly of how long your cases can be without being a problem.

https://www.sinclairintl.com/reloading-e...-prod32925.aspx

You may well have your eyes opened on factory chambers. I had one that had the longest allowable case length about 0.060 over SAAMI spec. It still shoots good but it was a learning experience. I also had one fellow doing a custom for me lie and tell me a chamber was 0.010 to the "shelf" and dang if it wasn't 0.070 long. Not a happy camper was I. With that chamber I theoretically would never have to trim based on the safety issue of too long a neck.

Greg
 
Update: My buddy traded me some of his processed brass. He used a small base sizer die. I do not believe that is the issue. He is running an AR-10 chambered in 7.62x51. There is more headspace in his rifle than my Savage bolt action.

Now I really have some experimenting to do!
 
Greg, those chamber gauges look like a potential time saver. I'm going to buy a 7mm one to start with. I have a 7saum that has gave me problems working up loads with the heavier vld bullets.
 
While I've not done it intentionally, I have trimmed some 308 to 2.000 and there was no issues and I wouldn't worry about it. I accidently trimmed some 223 brass to 0.025" under the min case length and reloaded them many times without issue in my ar until the necks split.
 


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