I'd picked up a box of Sig's new .300 Blackout hunting ammo: 120-grain solid copper hollowpoint. Supposed to run 2250feet per second, and a little digging around shows some very impressive gel block tests on expansion.
This is a long bullet, and the cartridge looks halfway like something from a sci-fi movie. Not having any gel I just wanted to see how this cycled through my rifle, and what kind of accuracy I would get.*
*Remember that this was after forty-something .45-70 rounds; probably should have shot this first