It's made to fit with most. I can't say it'll be a perfect match with each and every manufacturer but we strive to stay + or - .001 with our CNC machines for this very reason. I can't say how close other manufacturers stay but I've had it on a rock river upper and it fit.
If you're interested check it out at
www.blacksheep6tactical.com. I've got them in stock and ready to ship.
BlackSheep6
Manhattan KS
07 FFL