This was done to help those wanting to remove the stock handguard and install a free float on the DPMS Oracle 308. Non-Free-Floating Direct Replacement for All AR-15/M4/AR15 Carbine and Mid-length Plastic Handguards The Troy Drop-In Rail is a non-free-floating direct replacement for all M4/AR15 Carbine length plastic handguards with a round.

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

Handguards For Dpms Oracle

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.

Features

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.

Function

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.

Final Thoughts

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.

Specs

• MSRP $365
• Weight: 16.6oz
• Length: 15”
• Includes: Barrel Nut and four attached picatinny rails
• Barrel Nut Inner diameter: 1.020”

Does your 308 rifle use a DPMS LR-308 pattern barrel nut and handguard?
AR/LR 308 style rifles use several different barrel nut and handguard standards, depending on the make and model. Before purchasing a handguard, please make sure you are purchasing the correct one. View our 308 compatibility guide for more details.

Why install a free float handguard?
One of the main benefits to free-floating a DPMS LR-308 is an increase in accuracy from reduced variability in the barrel harmonics due to sling tension. The traditional LR-308 configuration has the sling mount attachment at the base of the front sight gas block, so moderate changes in sling tension can change the point of impact downrange. A direct impingement LR-308 can never be truly “free-floated” due to the attachment of the gas block and gas tube, but the addition of a quad rail or other free float style handguard can help with accuracy and also provides a stable and convenient platform for attaching bipods, lights, grips and other accessories.

What do I need to install a free float quad rail handguard?
When planning your free-float project, take a close look at the type of gas system currently on your rifle. Most standard front sight gas blocks are held onto the barrel by either tapered pins or by clamps. Make sure you have all the right tools and parts on hand for disassembly and reassembly before starting work.

Step-by-Step Installation

As always, before working on any firearm make sure it’s unloaded and safe to handle.

- First, remove the original handguards using a handguard removal tool.

- Separate the upper and lower receivers and remove the bolt carrier group and charging handle.

- Clamp the upper receiver into a vise using a vise block and remove the flash hider and crush washer. The crush washer will not be reused.

- Tap out the gas tube roll pin with a #2 roll pin punch and inspect the front sight gas block. If it has tapered pins, drive them out with a cup tip punch from the small side. If unsure, measure the pin diameter on each side first. If the pins are difficult to remove, apply penetrating oil, let sit overnight and try again. Sometimes applying light heat to the area also helps with removal.

- If the gas block is a clamp-on type, use a hex key to loosen the set screws. Remove the original front sight gas block assembly from the barrel. If it sticks, gently tap on it with a soft-faced hammer until it slides off the barrel. Remove the handguard retainer and gas tube.

- On a bench block, align the gas tube through-hole (with the large hole facing down) into the new gas block and use a roll pin holder to start the roll pin. Drive the roll pin flush with the gas block.

Dpms Oracle Handguard Upgrade

- Remove the original barrel nut/delta ring assembly with the armorer’s wrench, then clean and inspect the upper receiver threads.

- Remove the anti-rotation screw from the bottom of the new handguards and unscrew the new barrel nut, removing it from the handguards. Apply a thin layer of high quality lithium moly grease to the inside threads of the barrel nut, install it over the barrel so that the lock ring faces toward the upper receiver, then hand-tighten the barrel nut.

- Set your torque wrench to 30 ft/lbs and tighten the barrel nut using your armorer’s wrench. Remove the torque wrench and loosen the barrel nut with the armorer’s wrench (never loosen with a torque wrench).

- Re-torque to 30 ft/lbs, then remove the torque wrench and loosen again. Torque to 30 ft/lbs one more time and inspect the alignment between the barrel nut hole and the gas tube hole in the upper receiver. This three-time torque sequence allows the threads on the upper receiver and barrel nut to mate more completely.

- Without exceeding 60 ft/lbs, tighten the barrel nut until the gas tube hole in the upper receiver and the hole in the barrel nut align perfectly. The holes should line up at about 35 foot-pounds of torque, and the gas tube should be centered in the barrel nut hole without touching the edges. Do not partially loosen the barrel nut to achieve alignment – if need be, loosen the nut completely and re-tighten to align correctly.

- Apply blue threadlocker onto the gas block set screws and slide the gas block assembly onto the barrel, making sure the gas port in the barrel aligns with the hole in the gas block. Tighten the set screws on the gas block securely.

- Next, loosen the lock ring and carefully thread the quad rail onto the barrel nut for a couple turns. Apply blue threadlocker onto the outside barrel nut threads and screw on the quad rail.

- Adjust the lock ring and handguard until the top rail (marked “T”) is almost aligned with the rail on the upper receiver. Use a strap wrench and carefully tighten the handguard until snug. Be careful not to overtighten; if too much torque is applied, it can misalign the barrel nut and gas tube underneath.

Dpms Oracle Quad Rail Handguard

- You can check for proper gas tube installation using the bolt carrier at this time: insert the bolt carrier group (without the charging handle) into the upper receiver and slowly slide it forward, checking to make sure the carrier gas key doesn’t bind on the gas tube.

- Take a reading with your level across the top of the upper receiver and compare it with the level of the quad rail. Adjust the quad rail rotation until it matches the level of the upper receiver.

- Reinstall the muzzle device with a new crush washer and align it correctly (flash hiders generally with the vented ports facing upward; muzzle brakes generally with the ports facing sideways).

Dpms Oracle 308 Handguard Replacement

- Then apply blue threadlocker onto the anti-rotation screw on the bottom of the handguard, install it, and tighten until snug.

Handguard For Dpms Oracle 223

- Reinstall the charging handle and bolt carrier group, then reassemble the upper and lower receivers and you’re done!