Our Black out Barrel extensions are available in all threads sizes for M-11 9mm, Mac-19 .45 acp, as well as all Master Piece Arms 9mm & .45acp. Threads sizes available are:
1/2x28, 3/4x10, and 7/8x9
$46.99 + shipping
http://www.usmachinegun.com/proddeta...rod=MPA45-0142
http://www.usmachinegun.com/proddeta...rod=MPA30-0109
http://www.usmachinegun.com/proddeta...od=MPA930-0107