Re: Compressing IMR 4831
First of all, since you have no other takers, I'll jump in here and give you my 2 cents worth.
Compressed charges can be good, up to a point. Consistent powder location in the case is the reason, reduces a variable.
I do not like to seat bullets on a case charged so full that powder kernels are crunched and broken by the pressure of seating the bullet. Powder burn rate is determined by the shape of the powder kernels, as well as the deterrent coating.
Granted, the number of broken kernels may be a negligable number and have a mimimal effect.
Heavily compressed charges can push the seated bullet back out of the case after loading, causing magazine length problems and jamming the bullet into the lands upon chambering a round.
How you are determining powder compression by percent is a mystery to me, I just used the "crunch" factor. A different powder may be the answer here.
edited to add: You may want to try using H4831SC (SC for short cut) if you are not already. The SC version allows for better load density and uses the same load data as the original. Sorry - just looked back and saw you were using the IMR not the H. Load data would be slightly different.
Paul
