Originally Posted by
gloob
This is also my experiece in multiple calibers. That even if your expander is 1 thous LARGER your bullet size, you still get 100% neck tension.
I personally have transitioned to 358 bullets for my 9's, and I pulled the last of my 356 reloads the other day. I installed some gas checks on those bullets and crimped/sized the checks to 358. Then... I had a dilemma.
I have a 356 expander that I use for jacketed and 356 cast. I have a 358 expander I use for my 357+ reloads. Well, I used the 358 expander, and my bullets seated nice and tight, even though the expander is 2 over bullet diameter. But to be fair, the checks on these bullets are tall and probably cover more of the seated bearing surface than not.
I believe 2 over on the expander will be right at the point of messing up neck tension, normally. But the "1 under bullet diameter" that is frequently recommended is definitely smaller than necessary, and IF your case needs expanding, an expander that is any bit smaller than the bullet won't expand the case all the way and will leave some potential for case swaging. And it won't increase your neck tension, despite increasing seating force/effort. The idea is right; to keep a safety margin. But going even 1 over still leaves a safety margin and still gets full tension. For the accuracy nuts, even with a hard cast or jacketed bullet that won't get swaged, a case that is too small also reduces concentricity/straightness of bullet seating. The bullet finishes the expansion, and the bullet is free to wobble a little compared to an expander plug that is rigidly installed to the press.
I'm not sure what fiddling you can do with an NOE expander. NOE expanders are pretty easy to set. As soon as you feel the expander step touching on your shortest of cases, you're done. Not sure what else you can do with it.
Yes, powder makes a difference, too. For faster powders you may need harder bullets and you might still not reach as high of a velocity before you have fouling/keyholing. Never used that powder. Unique is about as fast as I want to go for my cast 9mm, if I want max velocity. But my 9's are Glocks with a long throat, and I load my 9mm extra long.
I take it you're doing a taper crimp, to remove the flare? That's the one issue you can have when using off the shelf expanders that are "too big." The flare is more than necessary. Your flare is 5 over bullet diameter, using this expander, and IME you only need 2 if your cases have smooth mouths (chamfer them once, if necessary). Or 3, on rifle cases where you don't want to have to chamfer after each trim. (Or if your guns don't mind a bit of extra flare. My Glock 9's chamber a 362 flare on a 358 bullet, and I don't normally need to taper crimp them.)