So besides the gas block cant, there were also some dark splotches in the chamber that I couldn't get to clean off with Hoppes patches, and I couldn't identify (leftover cutting oil stains or something? I'm not a machinist).
It probably would have run fine, but I knew it would always bother me, so I sent it back. The new (or fixed? Not sure) one hit my doorstep yesterday. Everything is beautiful.
Took it to the range today, and got all of 12 rounds through it before it started pouring rain. Unfortunately between having an old school chrono, and very little 6.5c ammo (and at over $2/pop for factory) I shut it down since I need all the data I can get from each round. For the Larue, the day consisted of:
2 rounds at 50yd to get near zero.
5 rounds of factory Hornady 140gr ELDX at 100yd. Average 2621fps with the best ES and SD I've ever recorded from a firearm that I own; obviously a small sample size, but still. Group size 7/8ths".
5 of my lightest ladder test load that I put together this week, 38gr H4350, 140gr Midway seconds (likely SMKs) at 100yd. Velocity average 2425, group size 1".
Surprised that the gun ran and ejected both those loads to the exact same spot; I don't think any AR15 I've ever shot would do that with velocities that far apart.
So not a single bad thing to say today based on a very small sample size. Definitely looking forward to shooting it some more. Also I really need one of those new Garmin chronos.