Garand Thumb gets satisfaction with the 8.6 Blackout round saying it is the quietest round they ever shot. The 8.6 Blackout, developed by Kevin Brittingham and his team at Q, is often referred to as the big brother of 300 Blackout. It does for AR-10’s what 300BLK did for AR-15’s. The parent case is 6.5 Creedmoor, trimmed down and necked up for a .338 projectile. The heavier mass means more energy transfer on target, and barrels are run with a fast 1:3 twist for devastating terminal performance.