In a world full of extended rails, there are times when a carbine-length rail is needed. Whether running an SBR or simply going with a more traditional look, the shorter handguard has its place. This is where the Rock River Arms CAR length Quad Rail comes in handy.
The majority of the AR-15s I see at the range are carbine-length weapons with A2 front sight. Though I tend to run mid-length systems (and often use long handguards in conjunction with a low-profile gas block), the carbine length handguard offers a couple of distinct advantages: weight and rigidity.
If you are going for a lightweight build, but still want to have a free-float quad rail, then a carbine length may be for you. The Rock River Arms quad rail locks up solidly on a proprietary barrel nut by using a jam ring. Any handguard that uses a jam nut is going to be a bit more involved to install and properly align with the top rail on your upper receiver. To keep these lined up, some folks use a removable carry handle. I use my Trijicon SRS, which works well.
Once the handguard was installed, I took it out and ran it on a 5.56 upper. Given a moderate amount of vigorous handling, it held up well. I did not subject it to the type of abuse like I did with the Special Ops Tactical rail. I applied a significant amount of torque to the rail via a vertical foregrip. When shooting from a bipod the whole platform stayed quite stable.
Rigidity is a bit more abstract. Shorter rails, made of the same material and having the same wall thickness, will be more rigid and less prone to warping. However, The RRA carbine handguard will be more rigid than their longer versions.
The fact is that many in the shooting world are not ready to abandon the front sight bases on their carbines. Whether the reason is aesthetic or that they simply are comfortable with a front sight post (which I completely respect), they will not be looking for extended rails and low-profile gas blocks. The Rock River arms handguard is a lightweight, sturdy option priced very competitively at only $135 from the manufacturer.
-By Allen Cosby