Inside diameter is 1.3 inches you will need a block no larger than about 1.25 inches. Your going to have to remove the fsb to mount a ff tube less you get a shoddy two piece. You should be able to use a carbine tube for a midlength but i would contact mi to be sure
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." — L. Neil Smith
The problem with being stupid is you cannot simply decide to stop doing dumb things...
"I crapped my pants to avoid the draft!!" -Ted Nugent
Last edited by JonM; 07-11-2013 at 01:13 PM.