A lot is going to depend what your trying to put it on and if the rail is mil spec or even maker specific spec. The two I've had the most trouble with, especially when trying to use them together is ARMS and Springfield. ARMS seems to like ARMS rails the best. Springfields rail, at least the Scout type they have on their SOCOM's are not anywhere near "mil spec", so anything that is wont fit(that means forget LaRue). ARMS may or may not, so if your going to use a Springfield rail with one, you'll just have to see. It took me three trys to get one to work, and this one works fine so far. I tried two ARMS mounts on my AK's Ultimak mounts with no luck, but my LaRue mount and my GG&G mount fits it fine(the Ultimak is mil spec) The GG&G also works great on my flat top AR and the LaRue fits it fine too. The LaRue has a lever that is adjustable for tension, but it also has two recoil blocks that are to spec, so it wont fit on a rail that isnt. ARMS lever isnt adjustable and it only has one recoil block. They are repeatable if you can get one to stay tight. My GG&G has the thumb nut, and has been repeatable when removed and replaced, but I now see the also have a lever model. I have some BUIS's and some of their other products and their stuff has all been first rate. I've also used a number of ARMS rings and mounts without trouble(mostly used together with their own stuff) its just these last couple of lever mounts that I've had trouble with.
