headspacing

[jarhead]

Alright, well I am not going to be able to convince the Mrs that I really do NEED a Dillon so I'll be stuck with the Lee Pro for now.  So that decision is made.  Will carbide dies be worth the extra money?  I know that the 357 sig headspaces on the shoulder and from what I've read carbide are best suited for straight walls.  Also, since it's a bottle neck I shouldn't have to expand the case mouth, or should I?  And more, I read that longer bullets would not be suitable for the sig.  How can I tell before buying them how long they are and what is suitable for the cartridge?

[Blackhawk44]

You are right about the carbide dies.  Best use is straight cases.  I know there are carbide bottleneck dies but are used mostly to add life to the dies for commercial loaders turning out thousand upon thousands of rounds.  They still need to have lubed cases.  The use of Imperial Sizing Die Wax will probably most benficial to you.  Just wipe a little on a couple of fingers every few cases to lube them as you insert them in the shell plate.  I like to just pour a little rubbing alcohol on an old towel, pour on a handful of loaded rounds, fold the towel up around them and rub them around a little.  Pour them in a box and all lube is gone.  About the bullets, the best advice I have is that the cartridge was designed to duplicate the 125gr 357 load.  I would stay with 115-130gr bullets for most use.  You have to be rather careful working up loads for 147gr bullets as the powders used tend to peak pressure somewhat suddenly with the heavier bullets.  Belling the case mouths a tiny bit will help production speed a bit and lessen the chance of crushing a case.  Definitely needed if you turn to cast bullets.  BOL

[dave375hh]

Jarhead,

   The .357 sig headspaces on the casemouth not the shoulder. Heavier/longer bullets can cause a problem with bullet set-back because of the extra weight in the short neck. I use Redding dies and a Redding taper crimp die and have had no problems with bullet slip. Yes you do need to expand the casemouths or you'll crumple the neck while seating the bullets. I've seen data for bullets up to 147gr but I only load 115 to 125grs which the .357 sig was designed for. Without the high velocity it's just another 9MM. I've clocked 1420 with Speer 124gr Golddots w/Alliant Power Pistol. That's not guessing, that's over my Procrono @ 6ft.