PRI Gen III Free Float Carbon Fiber Forearm Handguard Review
Major Pandemic 03.18.14
My DPMS Oracle build has become one of my rifles that I use for testing new accessories. Previously I had installed a non-freefloated Troy drop-in rail, but I wanted to wring a bit more accuracy from my rig, which is a benefit of the free float tube. The Troy rail also transmitted a lot of heat to the support hand during sustained shooting drills, and it was a bit shorter than I wanted. Because I shoot mid-length systems so much, I kept occasionally grabbing the nice hot gas block on my carbine where the rest of my stock would be on my mid-length ARs. I needed a long, free float handguard so I went big without adding much weight by using the PRI Carbon Fiber Gen III Free Float Forearm Handguard.
Precision Reflex Inc. (PRI) has become a go-to source for many of my builds because of high quality, ergonomics, and innovation. The company was one of the first to offer cantilever scope mounts and a lightweight, heat dissipating carbon fiber forend handguard, which can take all the abuse of a harsh tactical environments. PRI also tweaks their versions of standard product concepts (such as the AR tools, billet upper Vise Block, and this QR scope mount), which make them more useful, .
Fit and Feel
When we say extended we mean extended on the 15” Gen III AR-15/M16 Free Float Carbon Fiber Extended Forearm. Once mounted, only about an 1” of barrel sticks out before adding a flash hider like the Phase 5 Tactical break that I added. You end up with that Dissipator forend, which looks different from everyone else’s.
PRI also offers this forearm/handguard in lengths from short carbine up to 15″ length, all with a choice of either dark earth, black, or natural carbon fiber finishes. Once mounted, the fit is outstanding and completely wiggle-free, which is big accomplishment for a 15” handguard. Messing around with the handguard after mounting, it seemed that any movement was actually the lightweight pencil profile barrel barely flexing and not the handguard. Overall it has an excellent fit and feel and is very comfortable to handle.
Carbon fiber has many benefits in addition to the cool look in its natural state. PRI is using wrapped carbon fiber not necessarily because it looks cool for forend handguards, but because it is one of the lightest and strongest materials available. It also provides a far more comfortable grip once the barrel starts getting hot. The massive 15” PRI Forearm is only 16.6oz, including the aluminum barrel nut and locking collar, which is about the same weight or lighter than a very light, rail-less aluminum rifle length handguard. Additionally, the PRI forearm delivers 12, 3, 6, and 9 o’clock picatinny rails and al while delivering less heat to the shooter even during sustained fire. Even with all this, it is still lighter than almost any picatinny forend.
The PRI 15” GenIII AR-15/M16 Free Float Carbon Fiber Extended Forearm includes four billet aluminum attached rails, one 8.5″ rail on top and three 3″ rails at 3, 6, and 9 O’clock positions. I decided to mount the rail with the long rail on the bottom for more flexibility to mount bi-pods and forward grips, but I can turn it around at any time.
Not being a fan of quad rails in general, these shorter rail sections seem a much more sensible setup all while maintaining both handling comfort and mounting flexibility. They’re also far enough forward that they’re out of the way of the hands.
The internal diameter of the tube is 1.56”, with clearance from the barrel center-line to the inside of the forearm a huge .78”. This allows you to mount those big fat barrels and still have plenty of room for your gas block or one of those fancy target barrels like a heat sinked JP Enterprises, which needs a little extra internal forearm/handguard space.
PRI also makes some of the best high quality armorers tools around, and frankly this was the reason I ended up with the handguard. I used my PRI barrel nut wrench and the very handy billet aluminum AR-15/AR10 upper receiver vise mounting in my shop vise; two handy tools that any lifelong AR tuner should invest in. An upper vise block and a quality barrel wrench will make barrel, handguard, scope, and sight mounting an order of magnitude easier. I use the PRI upper vise all the time.
Mounting the PRI 15” GenIII AR-15/M16 Free Float Carbon Fiber Extended Forearm is an atypical procedure that requires removal of the flash hider, gas block and tube assembly, handguard retainers, and the stock barrel nut and delta ring assembly. This can all be accomplished with an Allen wrench, flash hider wrench, punch, and barrel wrench, depending on you AR accessories.
Leaving your barrel attached, the new supplied PRI handguard locking collar is slipped on the receiver and then the aluminum barrel nut is installed and aligned to the gas port with torque somewhere around 55-65 ft/lbs. Generally I work the barrel nut back and forth until I can get it as tight as possible while maintaining base port alignment (sometime this means actually backing it off just a bit). Remember 65 ft/lbs is not really that much and does not require you to hang like a monkey from the barrel wrench.
Instead of buying a low profile gas block for my project rifle, I converted the stock DPMS Oracle gas block to low profile. Technically grinding will work, but I cut off as much as possible with the band saw and then dropped the gas block in my $300 Proxxon Mini-Mill and cleaned it all up. Looks good, fits under the handguard, cost me zero, and performs the same.
Once the gas block is mounted, the handguard is attached by screwing it into the handguard locking collar and ensuring that the positive keyed indexing pin on the handguard is matching up in the orientation you want the handguard. I like to use a little blue/removable LockTite between aluminum to aluminum contacts just to assure things don’t loosen up on me. Tighten the locking collar with a PRI handguard wrench or a strap wrench and all that is left was reattaching the flash hider and testing.
This is an outstanding, quality handguard that provides a huge amount of room to shoot off barricades and supports, and it provides plenty of room for your hands to move around. I generally abuse the crap out of my guns and that means occasionally really heating up the gun, but have you ever had a red hot barrel touch your leg after letting the AR hang from a sling? This barrel length stock greatly reduces the odds of that painful event occurring. I have dropped about ten magazines through the gun since mounting the PRI 15” Gen III AR-15/M16 Free Float Carbon Fiber Extended Forearm and it has not shifted or loosened at all, and my Troy fixed front sight mounted to the PRI forend has held zero perfectly.
Although a little cliche sounding, the statement, “not only does it look cool, but it runs and feels cool” is accurate. Nope, no more catching the freaking webbing of my hand on that hot gas block. This update has made this an easier shoot for extended periods and a little more accurate by moving the front sight about 8” further out front. Many think carbon fiber is fragile, but actually carbon fiber can take more abuse than aluminum or steel can in almost any situation — it just happens to be a bit more expensive. The only, and I do mean only, downside is the price. I believe this is one of the most expensive forearm/forend stocks out there for the AR, but this is one seriously solid piece of engineering that delivers on looks, ergonomics, strength, durability, and the cooler feel that only carbon fiber can provide.
- MSRP $365
- Weight: 16.6oz
- Length: 15”
- Includes: Barrel Nut and four attached picatinny rails
- Barrel Nut Inner diameter: 1.020”