Want to kick this off by saying this is excellent hardware. The machining, finish, and the way the top rail smoothy opens away from the bottom is even preloaded to eliminate rattle is very thoughtful and meticulous. Installation on an M249s was easy and the lock-up is solid. I also appreciate that the bipod-grabbing feature is removable if you have the PIP bipod or something else. Five stars here - something I would be happy keep forever if not for other options. My complaint, though, and why I'll be replacing this is simple. The top piece of the rail is only covering half the barrel. This is necessary to open the cover one direction but I would have liked to see it designed to open the other way - away from the carry handle instead. Installation of this handguard requires the heatshield on your barrel is removed and the barrel remain bare and in thumb-range if you do not have a foregrip installed. I'd recommend one of the smaller units from B&T, KAC, or anyone else that still permits use of a heatshield or the KAC mk46 rail that wholly covers the top.