good points, all. there's always going to be a compromise between maneuverability and control of the muzzle end.
a 3-pt sling on the M3 is just too long. even putting the CQB solutions patrol sling with that quick release buckle on it so that you can 'extend' the sling for transitions i find a bit clumsy. unfortunately, my M3 is the regular length, not the entry length.
with my carbine, when i move it to my side, it's mostly out of the way, but i'll still get hit in the knee/back of the legs with the swinging muzzle.
another option i might try with the M3 is to use both the single point sling attach point, AND the front sling point (instead of ONLY the single point attach point). the weapon can pivot around the single point attachment, with the butt-end free, but i might still have some control on the muzzle end. it's all about playin' around with different configs :-) live and learn huh?
cheers,
MM