Jump to content
308AR.com Community
  • Visit Aero Precision
  • Visit Brownells
  • Visit EuroOptic
  • Visit Site
  • Visit Beachin Tactical
  • Visit Rainier Arms
  • Visit Ballistic Advantage
  • Visit Palmetto State Armory
  • Visit Cabelas
  • Visit Sportsmans Guide

Daniel Defense RIS III Rail

Recommended Posts

Many are familiar with the RIS II Rail system.  Built to run a free float rail on a M4A1 Carbine, full quad rail, and still be able to mount the M203 granade laucher - and keep the rail.  

It became standard equipment in SOCOM in 2005.  

They just released the RIS III Rail, and yes, I will be getting one.

Here's one writeup on the release, from Guns & Ammo magazine:


Daniel Defense RIII 5.56 NATO Rifle & RIS III Rail

Drawing on its long history of providing premium rifle components to U.S. Special Operations, Daniel Defense has updated its rifle and rail offerings with the RIII in 5.56 NATO and RIS III handguard.

Daniel Defense RIII 5.56 NATO Rifle & RIS III Rail

December 20, 2022By Tom Beckstrand

There’s a fair amount of interest in the guns of the U.S. Special Operations community due to the selection process associated with them. These guns go through a ton of abuse before they are ever fielded, and then they must perform under austere circumstances for years if they expect to remain. This makes for some compelling research and development for the commercial consumer because none of us have the time or money to beat on guns like the they do.

I like to keep track of what’s serving in this part of our military because it speaks highly of the companies that build the products for the market. Daniel Defense is one of those companies, and they’ve been making AR-15 forends — i.e., “rails” — for almost 20 years.

RIS III Mounting

The rifle issued to U.S. Army Special Operations at the turn of the century was a modified M4 carbine. It featured a quad-rail handguard that replaced the factory plastic handguards. This meant that everything touching or mounted to the handguard — light, laser, foregrip, etc. — might as well have been mounted directly to the barrel. The rifle’s accuracy suffered as a result.


In 2005, the United States Army Special Operations Command (USASOC) decided to upgrade their issued M4A1 and picked the Daniel Defense RIS II. This resulted in some significant improvements. The first was that it divorced the barrel from the forend (and everything mounted to it). The barrel became “free floating,” and accuracy improved while also becoming more consistent. Next, the handguard was increased in length from 71/2 inches to 91/2 inches on carbines with a 10.3-inch barrel, and 12 inches on the 141/2-inch barreled guns. That additional real estate mattered a lot when shooting from field positions with lights and lasers mounted. Finally, the RIS II allowed the military to attach a grenade launcher to the handguard instead of the barrel. In what should be a surprise to no one, this improved accuracy significantly on those as well.

RIS III Accuracy

Daniel Defense also saw the adoption of its barrels within SOCOM as part of a product improvement program. In 2015, USASOC decided it needed to further update its rifles with a better barrel. The M855A1 Enhanced Performance Round (EPR) had been out for a few years, and it was a higher-pressure load than anything previously fielded. The additional pressure was hard on the barrel’s rifling and SOCOM saw barrel life drop precipitously. They decided to adopt Daniel Defense’s hammer-forged and chrome-lined 141/2-inch barrel with mid-length gas system. (I remember being shocked that USASOC took AR-15 barrels seriously enough to come up with the right answer. Later, I came to find out that a couple of friends of mine were responsible for that project, so I shouldn’t have been surprised.)

RIS III Two Piece Design

Hammer-forging the barrel work-hardens the bore and makes it more resistant to wear than cut- or button-rifled barrels. The military previously used button-rifled barrels, so the new hammer-forging process gave them a measurable increase in barrel life. Lengthening the gas system allowed the bolt to stay closed longer and let chamber pressure drop before unlocking the bolt to extract the fired case. The M855A1 quickly earned a reputation for shearing bolt lugs when the bolt twisted to unlock for having a higher chamber pressure. Lengthening the gas system provided some much-needed relief. USASOC liked Daniel Defense’s barrel so much, they continue to use it today.

All of that tribal knowledge has made its way to the newest rifle from Daniel Defense: The RIII. This rifle features a forend that attaches to the rifle in the exact same manner as the RIS II, but it replaces the long sections of Picatinny rail on the RIS II with smooth, hand-friendly sections of M-Lok. M-Lok is SOCOM’s attachment method, so it’s no surprise to see it on the RIS III ($476).

Link to comment
Share on other sites

I have a Mk18 RIS II Rail on a 14.5" pinned gun.  That's my HD gun, my go-to carbine, above all other guns.  It's the ARFCOM first series receiver, that was the licensed reproduction of the MagPul receiver, and I got in right away, and got a low serial number.  ARFCOM ended up having 3 versions, I think I recall, and they kept changing things for the worse.  The first series was tits.  

I'll pick up one of the RIS III rails, in the 12-ish inch version, and build another HD gun.  If I can find the DD 14.5" CHF barrel, I'll get that, too.  

Quality rail, all the way.  The new gun going around this rail will probably be on Noveske receivers - but I have a hard time ignoring the pure sexiness of Aero's M4E1 receivers...   

Edited by 98Z5V
Link to comment
Share on other sites

My Mk18 runs flawless. And I've beat the living $hit out of that thing. Running it time and time again, without even cleaning it. I think she's down to only one of the gas rings left on the BCG. The others have twisted off over the "many" rounds put through her. And she just keeps running. Now that has absolutely nothing to do with the rail system that's attached to it. But the Daniels RIS II that the Mk18 runs, is every bit as good, if not tighter, than any other quad rail made for the AR-15 platform. Even compared to Geissele rails, that you can literally BEAT people with, if the rifle ever goes click instead of bang.

The RIS rail for the large frame AR is pretty much a unicorn at this point. Made from Unobtanium as it were. They can't be found. Anybody who has one......isn't letting go of it. Period. Hell.....I'm still looking for one too.

But Daniels's being Daniels's. I'd be willing to buy into the RIS III rail. I would guess, right out of the gate, that the platform is gonna be solid.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...