Because I'm resizing 45 Colt brass now, I'll use these as an example. When I check fired, empty brass OAL I get 2.70". The body of the case, roughly around where the base of the bullet would be, is .478".
Now, after I run these cases (winchester) through my RCBS carbide sizer die, I get an OAL of 2.80" and the body measurement has shrunk to .470.
Now, what I'm wondering is, how much of this case length increase after sizing is from the body O.D. being reduced and manifesting in case OAL, or, how much, if any, of this is from the case stretching in the die?
Yeah, I have a lot of free time...
Are you sure your readings are correct? If I am reading your post right, your brass OAL is increasing
100 thousandths of an inch. I would highly question that.
I have seen little case stretch in straight wall handgun brass in 44 Rem Mag, 357 mag, and 38 +P.
If you had said 8-10 thousandths stretch...maybe...but 100 thousandths...I don't know.
