RHF (Railed Handguard, Forward Controls) is based on the superb CMT UHPR Mod2, with full length 1913 rails at 12 o'clock, and MLOK at 3, 6, and 9 o'clock.
Since its introduction in 2018, RHF has progressively become more robust and durable with the deletion on lightening cuts and slots. It's gained some weight in the latest 2020 version, but we value strength durability far more than light weight. It directly contradicts the light weight fad which, like all fads, are rarely about improving anything for the end user.
RHF is machined from 6000 series extruded aluminum, its barrel nut is machined from 7075 aluminum, both are Type 3 anodized, while the rail mounting hardware is machined from 17-4 PH (patent pending). RHF also incorporates anti-rotation tabs.
RHF's inside diameter is 1.315" and compatible with most low profile gas blocks. The barrel nut diameter is 1.378", and a barrel nut wrench is included. It does not require specific timing.
RHF incorporates design input from Forward Controls, the changes include:
1. Omission of QD swivel attachment points. Location of the front sling attachment is left to individual users. The eliminates wear on the aluminum rail from steel QD swivels.
2. Barrel cooling vents changed to the classic round shape. One might say FCD is paying homage to Knight's Armament's RAS and RIS where meaningful modular revolution began.
3. Simplification of the already understated aesthetics of the CMT UHPR Mod 2 handguard.
Available in 15", 13.7", 11.5", and 9.5" lengths.
Weight of each length as follows (total weight, including mounting bracket and bolts):
15", 12.35 oz
Barrel nut torque: milspec 40-70ft/lbs
Rail clamp screws torque: 45 inc/lbs.
A single use (we've successfully used it half a dozen times without ill effects) barrel nut wrench is included.
Made in USA.
SIG M400 upper requires slight modification to fit RHF.
RHF is incompatible with BCM's Mk2 upper receivers without modification to the RHF's anti-rotation tabs, or to the upper receiver itself.
The scoffed up area is where RHF's anti-rotation tabs need to flank.
NOTE:URF requires the vertical portion of the upper, below the 1913 rails, to be TDP width (0.617 +0.000 / 0.010) . The anti-rotation tabs of RHF inside diameter is 0.6325. Some upper receivers have a wider section below the 0.617 width, at 0.6575, RHF will need the anti-rotation tabs relieved before they can go over the wider section of the upper receiver. Alternatively, the upper receiver's wider area can be relived for the RHF's anti-rotation tabs to go over.
CMT, which produces RHF for us, states:
The machined step under the pic rail where it blends with the forged surface of the upper does vary on some forged uppers and can cause a slight interference that can be usually be overcome by lightly pressing/tapping the rail towards the upper itself when installing.