If its the original pro target stripper, it can only fit in one positition, also it was all alloy( so there should not be a plastic insert?).
as for the groups opening up....... if its fine without it but then opens up when it put on?, then it can only be the muzzle break( its not an air stripper).
Try one from rowen there pretty nice and tidy up the muzzle nicely.
Last edited by fireblade; 16th April 2015 at 02:08 PM.