I got a replacement bolt from UT today, it's just like the first one. Actually it's a slightly better fit, but still not good. Very difficult to cycle, it sticks when fully closed. The bolt sticks in the carrier when fully compressed. And the bolt face isn't concentric. One side the wall is thicker than the other. That can't be good for accuracy or bolt life. Very depressing to have a new build and have one component screw it all up.
I said screw it and ordered a Young bolt, the new heavy duty Grendel bolt. I emailed UT and told them they could figure out how to make it right but this bolt isn't worth the postage back again and I definitely don't want another from them.