Quoted: world.guns.ru/sniper/sn00-e.htm Kind of a neat website. Is there any laws precluding the import of these?

Not certain other than they get very fussy about .50 being the limit, and would expect the alphabet bunch to round up and say no.

In my limited experience, the Serbu shark brake rules. A local guy has an 18" AR upper with this brake, and using surp rounds last spring I could one hand it with only a few inches of jump back along with side blast clearing adjacent tables.

There are also .50 spotter rounds, or .50 shorts. Made to mimic heavy shell trajectories, these bbls were along the heavy guns and launched a cheap marker round to adjust aim before the big ones were sent. Bullets are pretty much the same but the cases are shorter.