I tried one out, they work fine. I replaced the rear "thumb" screw with a cap head bolt to get rid of some of the bulk. Just make sure you set up the rear set lug properly. the NC star mount can correct for an out of spec receiver, that rear lug is whats used to do it.
If you unclear what i mean by "rear lug" if you unscrew the rear thumb screw completely, you find the piece that it screws into is actually a lug that screws in and out and has a set nut on it to stop it from moving. Just make sure that that piece is screwed in the correct distance to make contact with the receiver. If the mount is pointing "left" (relative to the receiver) screw it in; if the mount is pointing right screw it out a bit.
Once the left/right issues is resolved, crank on the set nut and lock tight that ##### down tight, you will never need to move it again on the same gun.
People harp on them, but these are actually decent mounts, they are just super bulky, a little heavy and a bit tricky to setup. but they let you use irons still, and if you have a out of spec receiver you can use the mount to correct for it instead of your scopes internal adjustment.
