Flasher,
You didn't mention caliber but since you're talking the "Scout" rifle concept I'd guess you are primarily interested
in the .308. I've had the 16" barreled Ruger Compact in .223,.243, .260 & 708. Of those only the .243 displayed enough muzzle blast to be of concern. I made the assumption that it had more to do with velocity than caliber......
FWIW