First let me tell you that I looked for this exact problem on the forums but did not find the answer. Maybe I missed something but here goes..
I'm using RCBS dies # 19112. Carbide .45 cal Colt.
These are in a Hornady L-N-L progressive press @ station #1.
I measured the O.D. of the once fired "R P" ( Remington Peters) cases at the mouth prior to sizing and removing the primer. They are straight walled cases, and the measurements read 0.470 O.D. @ the mouth and 0.4735 O.D. @ the base.
I ran the case through the die and looked at it again and could see what appeared to be a very slight "bulge" at the base. I measured it and found that the base measured 0.474 but the mouth end now read 0.468. So I ran a few more dry and then tried just a touch of RCBS case lube and got the same results. The effort to run them did not change at all by the way.
So the mouth was now actually smaller than it had been, so the sizing step worked.
According to Hornady's Handbook of Cartridge Reloading 8th Edition page # 1007, the O.D. for this cartridge should be .480.
The I.D. that I'm getting is .454 before resizing and .446 after resizing. I know that when it gets to the expander die it will open up enough for a .452 cast bullet to be started, but I'm concerned about the slight bulge.
I'm assuming that the case is not totally being resized. The visible "Bulge" starts 0.398" from the bottom edge of the case. This would make me believe that the case is only going 0.876" into the die.
The O.A. length is now 1.2835" so the case stretched a bit. Before sizing it measured 1.269".
O.K. that's a lot of fine measuring but from what I can gather, the sizing step is making the case longer and the O.D. is getting thinner making the base look fatter (it's not really- it just looks that way).
Is this what should be happening? Should the case be completely resized top to bottom or is it O.K. to have about 3/4" of it resized and call it a day?
I know that I've got the die installed properly and it's tight in the press. It's adjusted per RCBS instructions.
If any of you have had a similar situation, please let me know. If I ever figure out how to post a photo, I'll put one up to show what I'm referring to.
I have not shot any of these rounds yet. As soon as I do, I'll post a follow up.