new .308, brass shrank after firing… question before proceeding

[dcnyli]

Custom .308 with new schneider barrel and apparently there's "0" headspace(this thing is less then .5moa with FGMM), I've been using FGMM 175g ammo and my plan is to reloading that fire formed brass with Varget/175g VLDs…

after firing the brass shrank in length, and at the base of the body grew .001", I just want to confirm how I proceed before i do.

My thinking is this, I was only going to neck size the cases and keep rolling, trimming them only if they end up longer then the original unfired brass. I hadn't planned on shoulder bumping/FL sizing, only FL sizing if I use some of my other federal brass from the .308 prior to it's new barrel.

does that make sense? I have done a considerable amount of reading, but never came across what to do if the brass shrinks….

also with zero headspace & shrinkage, the primers had a slight crater(also my firing pin was purposely flattened for better ignition), was that just from the pin shape or is there already that as one "pressure sign" since there is virtually no room for the brass to expand? Will that effectively increase case pressure on my loads once i begin to work them up

Thanks for the help fellas..

i'm using a redding comp bushing neck sizer & redding comp seater with VLD micrometer/RCBS rock chucker press

 

[former naval person]

When you expand a piece of brass to fit the chamber it shrinks a bit. You have to expand a bit when firing to seal the chamber. The base grew .001...so there was room for expansion. JMHO

 

[dcnyli]

yes, but it shrank in length which is where I was confused.

 

[Spencerhut]

Shrink on firing is normal. Resize, trim and go on with life.

 

[former naval person]

Full length size a couple and measure them. I'll bet they lengthen a bit after sizing.

 

[dcnyli]

I'm ok with the shortening, just hadn't come across it in my readings. I was aiming towards using the brass fire formed in my reloading instead of FL sizing

I agree though, makes sense they would regain some length after resizing the entire case

 

[richidaho]

I agree with "former naval person" and "Spencerhut" both are correct. I see no reason to full-length size your brass in this case (bolt gun); anneal brass (keeps brass supple), neck size (to fit bullet), and trim (for consistency) and shoot them up.

Rich L

 

[dcnyli]

thank you for chiming in, and thank you to everyone for their input here. I'm glad I asked… It's a little nerve-racking to start reloading and you've all been very helpful on this thread.