I want a .22LR man-portable minigun with built-in all-steel cans - yeah, not gonna be that great a suppressor, but it'd sure be sorta spooky.
I'll bet that a system, along with 10,000 rounds, could be schlepped by one grunt.
Couple it with motion detectors for an automatic firing system, and you'd have one heck of an air-droppable perimeter defense system. Set the thing to oscillate both side to side and vertically (to gain coverage out to 400 or so yards).
Yeah, I know. Little slow moving bullet. You wanna stand in front of a few dozen, even at 300 yards?