The 8.6 Blackout scales the 300 Blackout concept up to a 338 caliber bore, and heavy subsonic class loads are the entire point. Ultramax feeds it a 300 grain boat tail hollow point match bullet, the weight built to run quiet through a suppressor while carrying serious mass to the target.Factory 8.6 Blackout ammo is still rare, so a production 20rd box matters to anyone feeding a bolt gun or large frame AR in the chambering. For hog control at night over a can, or simply proving out a fresh build, loaded ammunition with a proven match bullet takes one variable off the table.