Advice please!

[farmer7]

Hello,

 

I have a 100 Lapua .308 cases (once fired, but not from this rifle) which I have run through a redding body die and then neck sized. Can I work up a load from here or will I get different results on the next loading (after fireforming in my chamber).

 

I dont need maximum case space with the charge range I'm using with N140, so case capacity isn't a concern. But I just cant figure out if pressures will be different after forming on the second loading or on the first loading will the pressure be the same as it will form to the same size ultimately.

 

Does peak pressure happen before the case is fully formed or after?

 

Do I have to form them before load development?

 

I hope this makes sense!

 

Thank you.

[Andrew]

If you are planning on neck-sizing only from here on out then you will probably get different results than from the fully sized cases. What will you do if you get an excellent load with the fully sized cases? Neck size on the next loading?? or continue to fully size??~Andrew

[Jagged 77]

Providing you have only used the body die to just bump the shoulders and body enough to fit your chamber (as opposed to bumping everything back to factory specs or tighter) my prediction is you will see little difference. I say this as I frequently alternate between neck only and body die / neck sizing on my 308 loads and don't see any change. You will find that you can only neck size for 2-3 firings before needing to bump back with the body die again (depending on how hot your load is). Once you have found a good node on load work up it is usually tolerant of a small change in case capacity.

[farmer7]

Providing you have only used the body die to just bump the shoulders and body enough to fit your chamber (as opposed to bumping everything back to factory specs or tighter) my prediction is you will see little difference. I say this as I frequently alternate between neck only and body die / neck sizing on my 308 loads and don't see any change. You will find that you can only neck size for 2-3 firings before needing to bump back with the body die again (depending on how hot your load is). Once you have found a good node on load work up it is usually tolerant of a small change in case capacity.

Thank you. Thats what i hoped! Thats also what I do neck size and bump back every 2nd or 3rd. Just wasn't sure if a load would behave differently with new or fireformed brass.

[Jagged 77]

Thank you. Thats what i hoped! Thats also what I do neck size and bump back every 2nd or 3rd. Just wasn't sure if a load would behave differently with new or fireformed brass.

 

No problem. Each load / rifle combination will perform differently of course and the proof of the pudding will be in the eating. However I think if you correctly identify a good accuracy node it will be tolerant of a couple of tenths of powder and case variation.