Troy TRX rail and their gas block which is full length. Get the 13" for a carbine

Originally Posted By TacticalBlack19:
I want to remove the front site, add full length rails. I do not need some tier 1 top of the line items.
With rail handguards you
really notice the difference between different quality levels. If there's a part you'll not regret splurging on, it's a quality rail handguard.
For a quad rail I still like the older DD M4 design, the newer Omega X are also nice though. For the low profile block you want a "clamp on" style, not the type with a set screw when used on a barrel that has taper pin scars. Daniel Defense also makes a nice clamp on gas block that's trim enough to fit under virtually any rail.