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thedad,there are gigs and gigs of threads about sizing a case, the objective is to get the shoulder out of the way, best way is get the shoulder out of the way is over size it, full length sizing should size the case to minimum length/full length size, that should be accomplished by adjusting the die down to the shell holder with an additional 1/4 to 1/2 turn, when a case is sized according to the instruction (example 30/06) the case length from the head of the case to it's shoulder is .005 thousands shorter than the length of the chamber from the bolt face to shoulder of the chamber.
When I build a rifle and ream the chamber I do not finish the chamber until I have test fire it, I leave the chamber .010 short then size/form cases to fit. I form cases for short chambers by placing a .012 thousands thick feeler (leaf) gage between the deck of the shell holder and bottom of the case being sized (I do not use 5 time fired cases), Lee shell holders allow for more room, the .012 feeler gage represents .017 thousand head space with the perfect go-gag length chamber, all that is necessary is to get the shoulder out of the way, and when using your new tool, the neck must be trimmed back, without the tool, seat a bullet with the flat end out and even with the end of the case mouth, then start making attempts to chamber and if necessary trim. check etc., until it chambers. When the shoulder is moved back the neck gets longer, measure before and again after.
Again I use forming dies, the most versatile forming dies are are for the chambers that use the 308 W as it's parent case, again, because they are short.
Again, full length sizing should get the shoulder out of the way, I use the feeler gage to add an additional .010+. When using a forming die I can move the shoulder back an additional .200+, advantage? added neck length.
F. Guffey
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