People have made 'em... There's a dumbsh... er... vendor who sells cleaning crap (he'll gladly sell you a stainless brush to clean your rifle with... In fact, according to him, they work best....). He's got a few cases necked down to tiny calibers, and if he gets going, why, they'll turn a coyote inside out if they just pass nearby... 8,000 fps and all that...