fwiw, i'm on day 21 of my experiment. AXSR 300nm @ 410+ yards, 1 shot per day across a holler one ridgetop to another, different times, positions etc. only 2 days rain. None of the misses were from prone or when raining.
17 hits, 4 misses - 81% hit rate
11 of the hits are inside IPSC A zone (1 7/8" tall by 3 7/8" wide box in upper half of the 6"x6" head).
IOW 11 of 21 shots are in a .5 x 1 MOA rectangle. The remaining 6 hits are in 1.5 MOA square.
1 miss was just low and due to ammo (at least, i assume as the garmin read the fps about 5 STD below mean.)
1 miss was just left missed wind call.
2 miss were just high, i attributed one to light and the other to wind moving up the face of the mountain toward the target, but just a guess
I will say, I think i'd have more hits shooting my 6dasher or 6.5x47. 300nm seems a lot less forgiving.