Doesn't tighten on the rail - NcSTAR GEN II SPR Cantilever QR Scope Mount

Theoretically, this should work great and I was looking forward to getting it for my new Saint Victor AR rifle. However, the cams are too small to tighten on the Picatinny rail; it's sloppy loose - I even tested it on the included rail for the red dot. Also with this mount, my Swampfox Arrowhead LPVO 1-10X24 scope is too close to the flip-up rear sight and would rub just a tiny bit (yes, in the down position). I don't need a quick disconnect mount if I have to remove the flip-up rear sight to get adequate clearance.