For frame of reference, USSOCOM chose the "lowly" Harris S for their new Advanced Sniper Rifle (ASR) Barrett MK22 Deployment Kit. That seems to be a rather pragmatic application. They tested, evaluated every thing they could get their hands on, and had no constraints in selection process......other than what supports putting rounds on target.......reliably...and what will "take a lickin', and keep on tickin'" despite young Jarheads under grave stress.. According to Kevin Owens of the Development Team, the Atlas has more play requiring more pre-load and recoil management technique than the Harris......and was cheaper. Wait, that last part can't be right coming from my government????? I'm sure they'll figure that oversight out better. Harris mounts to hand guard via M-Lok and QD lever attachment. Recently received it and haven't removed to further inspect yet.