Requirements for Replacement of Currently Issued 5.56 M-855 and 7.62 M-80.

[LRRPF52]

Oh, I also have the new unubtanium Lapua .260 Rem brass, so this will be fun on a few levels for me. I've been necking-down Winchester 7mm-08 brass, since it is harder than the Remington .260 brass, and I've gotten up to 4 re-loads out of it running pretty hot loads. I'm pushing 123 Scenars at 2960, and 130 Berger VLD's at 2850, with cratering primers, and light ejector swipes. I reached my, "Ok, this is too far..." load when the naked 130's pierced primers and my chrono made huge jumps and drops over 100 fps in the spread, so I came down from that quite a bit. I had to dig the remains of some primers out from around my firing pin when I broke her down, and my firing pin retaining pin was badly disfigured. I'm thinking if I got my firing pin hole bushed and the pin matched to it that I could prevent that, but I'm already well over book figures. The AR10 bolt and barrel extension can take a lot more beating than a 5.56 one...

I'll have to take it easy with the 144 FMJ's, and drop down quite a bit for starting loads. I'm using N540 for the .260 right now, and getting .75 MOA with my initial loads, so it has some room to be tweaked.

LRRPF52