Originally Posted by justgoto
I would guess that you have full length sized the case too short. That would give you a young case life and possibly case head separation in just a few firings. I sure would like to see the whole case.
I neck size only, unless I have insertion/extraction problems.
But if you are set on using the full length sizer, I would set-up the full length die to where it just bumped the shoulder back a smidgen.
Thanks for the feedback, Justgoto, Gene and Boomtube. I really appreciate your thoughts.
So, . . . here is some of the rest of the story . . .
I bought three other sets of dies:
Neck only sizing die set from Forster
Neck only sizing die set from Lee
Full length sizing dies from Forster
. . . and was working with my Dad, remotely (he had all the reloading equipment) to try to get the FL dies set up for "minimum shoulder bump", very similar to what you described. I wanted to bump the should .001 or .002 (as opposed to neck-only) since these loads are for hunting. We have a head space measurement tool from RCBS, and were making measurements as the die set up was adjusted similar to your recommendation. We got it set so that it would do the full neck, and just touch the shoulder (based on permanent marker ink being disturbed), but when we tried to go a little further, there was no measurable change in headspace measurement. So we tried to keep cranking down on the die adjustment. After much much more than 1/8 of a turn (1/12, 1/8, 1/4, 1/2, whole turn, etc. . .) there was still no measurable change in head space. (!)
At that point, we were both scratching our heads, so Dad brought me a spare press, along with most of the equipment I would need to do some reloading, and I am going to try to reproduce the same results, or see if I can't figure out how to get the minimum shoulder bump I'm looking for.
In the meantime, Dad did some more reloads with the RCBS FL dies, which produced the latest results. Great groups on the target, but funny powder marks on the brass. (It may be that there were similar powder marks on the brass in previous reloads. I didn't pay that much attention to them, but I am seeing some evidence of it on older brass.)
At this point, I'm tempted to
1. try using my IMR 4831 recipe, which may produce higher pressures,
2. try annealing the brass (though I don't yet have the set up to do it) and use the Retumbo recipe again,
3. try using the neck-only sizing die . . . though this may not fix the issue if the brass has already been work hardened from too many cycles through the FL dies.
I suppose I should try all three.
Has anybody had a similar experience where the measured head space didn't seem to change, even as the dies were adjusted down more and more?
Seems bizarre to me. Maybe the dies are designed to go only so far, to stay within SAAMI specs?
Gene, here is a picture of the whole case, for three pieces.
I'm not sure if the resolution will be fine enough for you to see what you're looking for.
Notice that two of the pieces have powder on the necks, and a little area on the shoulder, while one piece has powder covering almost the whole area of the shoulder.