He has fired 1000 yd. 3-shot groups down to 3.5 in
Completly meaningless data (if true). The standard for measurement is 5 shot groups. Best group means nothing. If he can really shoot like this he should compete and totally dominate the 50 BMG 1000 yd contests.
What matters is typical 5 shoot groups. The AR-50 is a great gun, but it's not a BR rifle. If you want to make bug holes, go with the proven winner, ALS - much more accurate gun and less money.
Take a look at ALS FCSA Match Results
Three guys won in Raton using them ALS dominates 50 BMG World Championships
Even tho there are a lot more AR-50's made, you don't see them winning