SO I measured my brass before and after shooting my m1a and I measured a average elongation of 0.011". I want to reload my brass and was wondering if this is beyond reasonable limits for a .308...Should I somehow compensate by resizing, anybody have experience with this?
headspace compensation
- Thread starter ALMAR
- Start date
Ideally you want to knock the shoulders back about 0.003-0.004.
Make sure they chamber freely.
If you don't know what you are doing or are new to the platform you may just want to fully resize them.
Not enough wiggle room and you may have an out of battery detonation.
Make sure they chamber freely.
If you don't know what you are doing or are new to the platform you may just want to fully resize them.
Not enough wiggle room and you may have an out of battery detonation.
I've played around with shoulder bumping my M305 loads as Yo suggests however I have not seen significant accuracy benefits. Further, even resizing to maximum 308 SAAMI spec., my brass survives much longer than I'm comfortable using it. I've pushed it to 10 reloads then thought (and was advised) that this was starting to play with fire. I'm now saving the 10+ times reloaded brass for a bolt gun.
I now fully resize to SAAMI spec just so that I don't cause a problem for any friends at the range when we're chatting, swapping ammo, etc.
I now fully resize to SAAMI spec just so that I don't cause a problem for any friends at the range when we're chatting, swapping ammo, etc.
Headspace absolutely has a lot to do with case stretching! If your shoulder is over SAAMI spec, that overage is added to the amount the neck stretches. Derrr.
If you are confident in what you're doing, I'd suggest bumping back .004. If in question, just FL size and trim. What dies are you using?
I no longer even try neck or partial full length resizing for my semi-autos and straight-pull bolt guns. I need to know that it will fully chamber and fire. Brass life might be extended, but it's not that expensive, and I have found rounds based on F/L sized brass to be as accurate or more accurate to other methods.
RCBS small base.
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In this instance, it has nothing to do with headspace. However, after thinking about it, 11 thou sounds like a lot of stretching. How are you measuring the case?
You don't need SB dies if you have FL dies. It's one or the other. And one or the other is required for semi-autos(levers and pumps too). Neck sizing will give you grief.
You don't need SB dies if you have FL dies. It's one or the other. And one or the other is required for semi-autos(levers and pumps too). Neck sizing will give you grief.
Im measuring overall all length with digital calipers and doing an average. I have the initial length at 2.005..i have measured other spent .308 brass that i collected froom the range (shot by other rifles) and they seem to be around 3.009 or so...The elongation is what bothered me, excessive elongation and resizing cycles is pretty bad for fatigue damage...
Like I said I was new to this...I ordered small base because it seems to be what others are using for semi's...I really don't was to have a out of battery but I don't want to rework the brass for nothing either, not that brass is a big deal to buy or get but still... I'm planning to get a good bolt action .308 sometime next year or maybe this fall...if you (or anybody) have experience using normal dies with this rifle let me know because I can still change the order I believe.
Measuring the fired case from your M14 clone can be deceiving, due to the gas port location the bolt can start moving to the rear while pressure is still in the barrel. This "pressure" as the bolt moves to the rear can push the shoulder of the case forward and make the case longer than the chamber as far as headspace/shoulder location is concerned. Simply put your fired cases can end up longer than the chamber depending on how over gassed your rifle is and the burning rate of the powder.
At http://m14forum.com/ you will find a sticky on the proper way to check a fired case and get the correct shoulder bump for your chamber.
You can always send me three cases fired with the gas valve off and I can verify your measurements and headspace.
Pm me if you want my address.
I replaced my bolt so my headspace is about 1.631.. I had to modify my case holder so that my shoulder got bumped back to 1.628...
Pm me if you want my address.
I replaced my bolt so my headspace is about 1.631.. I had to modify my case holder so that my shoulder got bumped back to 1.628...
