I have used both ar15 and 10 extensions from BAT in the past and I'm looking for a different option. For whatever reason they leave a 90 degree corner for the bullet tips to catch on after they pass through the ramps. I'm shooting 75 bthp and its flattening the bottom side of the tip as it scrapes it going by. I see JP makes ar10 extensions and that's what I will go with next time I spin up an ar10 barrel, but who is making a quality barrel extension for ar15's?