I posted this a month ago on slickguns. they are actually pretty decent rails.I have attached them to two of my rra lar15s. I have stuck an aimpoint pro, green laser, bipod, and fore grip on them without issues. There fixed foregrip does suck so avoid that one
it doesn't seat tight and will wobble back and fourth.
Extremely easy to put on, but didn't fit my Lar-308. 1 of the 6 that i have had, only had 1 screw(missing 3), but I will dig up some at the gun show next week.
If you order 4 of these the shipping comes down to about $3ish per item(at least for me to Ohio).
"From My Cold Dead Hands..." C.Heston (God rest his soul)