This rail is not 1913 spec. If you only need the proper width then its okay, but if you have an item that uses 1913 picatinny rail slots (bipod adaptor or such) it wont fit. The lands are too narrow.

Inside fins on the Glacier guards that came stock on my DPMS wouldn't allow the front nut to fit, but ground the sides of the nut a bit and then the nut would seat properly. But...the holes didn't line up perfectly either and it took a bit of wrangling, but I eventually got it to fit. Seems solid, but after a couple of days, I wound up just buying a quad rail. Three bullets for having to modify the product.

Holes did not align up on the rear for my Bushmaster

I have a Bushmaster carbine with factory handguards and this rail fits perfectly on it. It seems like a solid platform. No complaints at all.

I got mine for a double star 16'' upper and the holes did not line up on those handguards so I did some custom mods to it myself. It is solidly mounted now.

Holes do not line up on Bushmaster either.

It can quite easily be made to fit the M4 and CAR handguards, with a little bit of simple work. Other than that, it is great quality for the price.

This is to inform everyone that this item does not fit RRA r-4 handguard. The screw spacing is different. Seems to be well made but i can't use it.