So my curiosity kicked in again....
I did a comparison of a Lee and an RCBS resizing die, in 308 Win, and measured the shoulder headspace of 25 cases. I also measured 20 F-C loaded rounds. The same shell holder was used (Lee) in my vintage RCBS Rock Chucker press.
I started with the Lee, using the o-ring lock ring as supplied with the die. I noticed half way through that sample that the lock ring was not quite tight against the press. I did another sample later, using a split lock ring with the Lee die. The RCBS lock ring was the one supplied with the die.
The results are (inches):
Die Avg SD ES
Lee 1.568 0.0022 0.008
RCBS 1.566 0.0011 0.004
Lee - w 1.565 0.0011 0.004
Split lock ring
F-C ammo 1.566 0.0011 0.003
My conclusions?
The Lee o-ring lock ring can shift. The differences between the shoulder measurements of the resized cases - insignificant for my abilities. YMMV.
I did not measure the shoulder diameter, nor the case runout.
I did a comparison of a Lee and an RCBS resizing die, in 308 Win, and measured the shoulder headspace of 25 cases. I also measured 20 F-C loaded rounds. The same shell holder was used (Lee) in my vintage RCBS Rock Chucker press.
I started with the Lee, using the o-ring lock ring as supplied with the die. I noticed half way through that sample that the lock ring was not quite tight against the press. I did another sample later, using a split lock ring with the Lee die. The RCBS lock ring was the one supplied with the die.
The results are (inches):
Die Avg SD ES
Lee 1.568 0.0022 0.008
RCBS 1.566 0.0011 0.004
Lee - w 1.565 0.0011 0.004
Split lock ring
F-C ammo 1.566 0.0011 0.003
My conclusions?
The Lee o-ring lock ring can shift. The differences between the shoulder measurements of the resized cases - insignificant for my abilities. YMMV.
I did not measure the shoulder diameter, nor the case runout.
