Lube. That bullet holds a lot of it and if it ain't right, it ain't gonna be happy. I about fell out of my chair when I saw how much 748 you were using, I quit at about 34.5 grains, but shoot a little heavier bullet (165 or so).
My hornady manual shows a max of 38.9gr with a shorter OAL than I’m using.
Maybe I need to back it down.
This one may be a good candidate for powder coat testing. For now I need a functional hunting load to put some does down with.
I plan to shoot several does for the freezer and I would like to test the 308 hunting bullet out. I’m afraid I might be a little hard with the heat treated 50/50 but not sure with it being a hollow point.
I ain't gonna tell you that what you have won't get it done, but it's more coyote medicine than deer medicine. HPs are for slower loads, you can't make an alloy that will hold together without a jacket and not be too brittle in the end to not explode at 2100+ fps impact velocity. I'd be looking to knock off a couple hundred fps at the muzzle and step up a few ticks in burn speed. Something like 25-26 grains of Reloder 7, or even 3031 should work well.