Re: Cornmeal forming bad on a new barrel??
I neck down the 338 Lapua to 30, then form with COW and a toilet paper on top.
26-30gr of 800X, and COW jammed in tight with a rod = fully formed every time. [img]images/icons/smile.gif[/img]
If I wasn't forcing the shoulder "back" to be able to chamber it, which makes the longer neck, I might do what Bountyhunter does too, but then again I have to turn necks to .125" to chamber a round, so again, I can't.
COW does not stink, never tried cornmeal. Instant COW seems less abrasive, if it were a problem.
If I was blowin the shoulder forward and din't have to fit the necks, I'd seat the bullets into the lands and go clang some steel. The case surely doesn't know it's not formed yet, and it will be before it ever hits peak pressure, I assure you.
28gr of 800X and COW in the 30-338 Lapua Imp runs about 37,000 psi.
With this method during testing, 15gr on up formed the cases perfectly, the only difference was the very base of the neck where it's real stiff ends up getting more brass reamed out from the K&M fluted cutter than really needs to be, so I kept uping the charge until it blew out there a couple more thou.
Optimally, nothing down the bore except your tuned loads would be nice. [img]images/icons/grin.gif[/img] Some guys have a forming barrel chamber and use it. Necessary? Better, but I'm not sure it's really woth it IMHO.