Springback

[Semtav]

Has anyone accurately measured the springback of a cartridge when fired?
annealed - unannealed
full length resized - as fired

(chamber diameter at end vs dimension of cartridge at mouth)

[powderburner]

Brian that would be tight, hot, and a dangerous job,
Wouldnt it depend on chamber dimentions as well as charge and bullet weight,I am thinking there are too many variables to have to measure, to say one figure is accurate.

[Semtav]

I don't know never gave it a thought before. I'm going to start measuring a few before I relegate them to the tumbler.

[powderburner]

I think that the springback would be different in every chamber , I have zero in my thick wall brass and my pp bullet the bullet seats with the same pressure and I do not resize at all , my 44 does need about 2 tho, sizeing on the neck to hold the bullet , my tight chamber 45 does not move either , the inside is bore diam and the outside is chamber diameter , the case does not have to move to seal the chamber hardly at all and then drops out and does not need sizing, I have put a lot of loadings on both the thickwalled 45 and the tight chambered brass and have yet needed to tighten up the necks , I have to full length resize the 50-2.5 to get it to hold a bullet as that chamber is really generous,
you shoot a lot of different calibres it would be interesting to see how they change especially with some of your high intensity ctgs ,,,

[Semtav]

Just measured some Starline 45-90 shells that had been annealed a couple times ago. Not sure how accurate I can get, but most were less than .0005 smaller than chamber at the neck. ( 90 - 93 gr swiss 1.5)

[powderburner]

now let them harden up and see if they spring back differently..

[Rick Mulhern]

Semtav

This isn't an exact answer to your question but....this article is very enlightening to say the least!

http://yarchive.net/gun/ammo/cartridge_expansion.html

[Lumpy Grits]

The harder the brass gets, the more spring back. Right up to the case mouth/neck spliting due to work hardening.
That's why I now anneal all my rifle brass including .308 etc.
Gary