I would love an AR-prefer gas piston to direct impingement- in 6.8SPC and 308, however for home defense the 300BO is the winner I would think. Lack of noise, very soft heavy for cal projectile would help stop offender quick and less chance of over penetration.

Why gas piston, well the two most reliable military weapons the AK and SLR (FAL) are piston. The fact that Piston requires less effort in cleaning has got nothing to do with it, nothing to do with it.