I am loading for a friends rifle, 6-284. I am using necked down 6.5-284 brass from Norma that I purchased new. First testing was with 75 gr. V-max and H4350. Worked up using Hodgdon's data from 49gr., stopping at 51.5gr. at 3600fps. Didn't notice anything out of the ordinary untill measuring brass afterward. Using the Hornady tool, the shoulders on fired brass measure .020" longer than new brass. Have only been reloading a couple of years but this gives me pause. The rest of the guns I have loaded for have shown .005" growth or less from new brass. Case head separations don't sound fun. I have used the bent paper clip trick to feel around and dont notice anything but don't really know what an incipient separation would feel like. Visual inspection of the inside of the case doesn't raise any suspicions either.
What do you guys think? Would I be safe to proceed as long as I dont set the shoulders back more than a couple thou, or is one time stretching of the brass by this much enough to compromise it to the point I should abandon the project? Any advice is much appreciated, I can provide more detail if it would be helpful. Thanks.
Although that is a lot of stretch, the brass might have started out undersized (not familiar with Norma 284 brass). One, initial big stretch is probably fine. Most brass is going to crack from oversizing and being repeatedly stretched. And my experience with Norma brass is it's usually rather soft brass to begin with so it's a bit more tolerant. You could section a case or two to see if the dreaded incipient separation is present just to be sure and for peace of mind.
I'm assuming this a custom/rechambered bbl?
Casey
