Case shrinkage vs Headspace

[swerv512]

what if i fired brass twice and see ZERO case growth. does that mean that i'm headspaced ok- or does it take longer for some brass to stretch than others

[ar15barrels]

what if i fired brass twice and see ZERO case growth. does that mean that i'm headspaced ok- or does it take longer for some brass to stretch than others

Are you talking about shoulder length or case length?

[swerv512]

i was referring to case length, but i do see why you asked. i'll be measuring shoulder length now.

[30Cal]

i was referring to case length, but i do see why you asked. i'll be measuring shoulder length now.

You'll need a gage (case mic or comparitor) to measure the shoulder.

[swerv512]

already have some on the way!

[bridgeport]

This is exactly why it is a good idea to measure the shoulder. Lets say you pick up a bunch of brass at the range, and it was fired from a few different
rifles. Each batch of brass will conform to the rifle chamber it was shot out of,
(of course) but you want this brass to fire properly from your rifle, so you can take a fired casing that came from your rifle, measure, set your dyes to push
back a couple of thou, and then run some pieces and check them to make sure
the shoulders are getting sized evenly. Some brass sizes differently than others so always check different types , say Winchester or R-P, to make sure
things are working right.

[swerv512]

Oh my GOD!! It's 1am early tuesday morning and after unwrapping my rcbs headspace gauges around 10pm last nite, I finally get it!!

I averaged 10 once fired cases in my Rem700 .308- averaging 1.6275 (a little tight, but who cares because i'm reloading, right.)

so i set my sizing die down and after 3 dummy rounds i'm set at 1.625 or so according to my headspace gauges. badaBAM!

[bridgeport]

I would not even attempt to reload without gauges. There is simply not other way of telling where the shoulder actually is when full length sizing. Isn't it
interesting how the brass stretches when the dies are not screwed down far enough.... this is no laughing matter though. Even if you fire a precision bolt rifle,
it is still imperative to know that you are ending up with properly sized brass for your chamber via the neck sizer, knowledge is your friend.