this is a very good RIS system.
i converted my short barrel'd CQB m4 into a long, 550mm bareel using this RIS and it fits just right with my 10.5inch outer barrel and silencer. the gun looks beasty and my friends and teammates all druel over this.
my gun now fires about 150feet at 450fps very accurately, so if you're a sniper type of guy (specifically autosniper) buy this RIS if you intend to use a long barrel.
but at the same time the RIS has a little sharp finish and rubs against your hand. i suggest you get a bipod up in front and a foregrip a little toward the other end so you can move them around easily. It helped me ALOT to have a sling, but to do that you also need to buy a rail sling swivel. also, you need an EXTREMELY long outer barrel to fit a regular, triangular m4 front sight into this RIS, so i suggest buying a rail-attatched, folding front sight with it. i mean, it looks better with a silencer, anyway, haha.
cheap compared to the features
a bit heavy, but hey, its fully metal
more money needs to be spent on;
-foregrip or gloves
-frontal iron sight
Rating: [5 of 5 Stars!]