Guys--

A big tip of the hat to all who suggested the necks were being overworked.

I sent the sizing die and some once-fired and twice-fired brass off to Redding and they honed out the neck. Tried it out yesterday and twice-fired cases now come out with .002" or less runout *every* time.

Thanks!

John

Ah John, you stole my thunder! Redding is good about that, or even sorting dies to find one with a more amenable fit. Your die was sizing down way too much as pointed out by previous posters, but you know that now. FWIW, if you run into this again, a couple of things to try in the interim: Let your dies float, ie. don't lock them down. Secondly, try sizing and expanding as a two part operation, doing the expanding on the ram upstroke(how else?), with the expander floating.

Had a similar experience with K-Hornet dies from Redding a few years back, and after exchanging the sizer it will produce about 95% of reloads at .002" run out or less.

I just went through this with 2 rifles.If your fired cases fit back into the chamber there is no reason to full length neck size. The fireformed case is concentric on the case axis until you pull the expander ball back through the neck and it stretches the hell out of it and makes it crooked. A bullet crooked in the case enters the barrel crooked and exits crooked. I have gone to either Redding or Wilson neck sizing and inline seating dies. Go to L.E. Wilson online and look how their inline seating die is made. Your bullet will have no option but to be seated straight. The only problem is if they have the reamer for your caliber.http://www.lewilson.com/index.html. Good luck.

John,
I think your going overboard on the 375 H&H a round made to shoot big nasty animals at minimum range,say up to 300 yards....Its not a bench caliber...I just resize and shoot mine and it shoots an inch almost every time for 3 shots...The caliber, the quality of the brass, the design of the case, and several other factors really offsets the need for the type of play your getting into..

Letting something like that bother you in the least tells me you got way to much time on your hands! but on the serious side, that kind of reloading is for a different ballgame, not big bore cartridges...It works at the benchrest only, not even particularly usefull at the varmint game.