I reloaded about 250 rounds of .223 last night, using my 2x-fired brass, mostly nickel plated R-P, and some mixed headstamp unplated brass. All the brass was trimmed on a Giraud trimmer to about 1.751-1.753 range.
After shooting it all today in a Colt AR, I cleaned and resized the brass, planning to reload it again. After resizing it, I was surprised to see that most of the brass now measures 1.748-1.750
One of the cases was only 1.739 !
I don't know if my brass got shorter during shooting or resizing as I did not measure the brass prior to resizing it.
While I used an RCBS X-die to resize this brass today, I did so with the X-die mandrel raised well above the case mouth - about 8 or 9 turns, so I don't see how the X-die could have acted any different from any other sizing die, as I wasn't using it's unique "X-die feature" which keeps the brass from growing longer.
***Edited to correct the typo in case length - when posted, I left the digit "7" out of the measurement!
Any idea why this brass got shorter and should I be worried?
After shooting it all today in a Colt AR, I cleaned and resized the brass, planning to reload it again. After resizing it, I was surprised to see that most of the brass now measures 1.748-1.750
One of the cases was only 1.739 !
I don't know if my brass got shorter during shooting or resizing as I did not measure the brass prior to resizing it.
While I used an RCBS X-die to resize this brass today, I did so with the X-die mandrel raised well above the case mouth - about 8 or 9 turns, so I don't see how the X-die could have acted any different from any other sizing die, as I wasn't using it's unique "X-die feature" which keeps the brass from growing longer.
***Edited to correct the typo in case length - when posted, I left the digit "7" out of the measurement!
Any idea why this brass got shorter and should I be worried?
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