MRGG At Home: One Of SOCOM’s Lesser-Known Rifle Programs [BUILD]

U.S. Special Operations Command has it almost as good as we do when it comes to getting their hands on new rifles. Their unique logistics and acquisitions process does not require the multiphase, multiyear trial and selection process mandated by the rest of the military. This allows them to fulfill niche needs and build specialized capabilities rapidly among their ranks of uniquely trained operators. 

As the rest of the shooting world argues back and forth about the Next Gen Squad Weapons program and it’s 6.8x51mm cartridge, SOCOM awarded a contract for a similar but more discreet project a couple of years prior. In 2023, Geissele Automatics won the contract for a program known as the Mid-Range Gas Gun. 

It’s interesting to note two things about this program. One is the use of the term “mid-range,” considering that the specification was for engagement ranges of over 1,000 yards. Program language further cites the requirement for 6.5mm Creedmoor, defining it as an “intermediate cartridge.” We know that 6.5 Creed is consistently a 1,200-yard cartridge. For many of us, this is at or past the ragged edge of what we can do as shooters.

MRGG AT HOME PARTS LIST

Not that long ago, even military sniper rifles like the M21 or M40 were considered 800- to 1,000-yard assets on the battlefield. But with a number of record-shattering sniper engagements across the mountains of Afghanistan now cemented in long-range lore, 1,000 yards isn’t the far reach it used to be. Currently, three of the top five longest recorded sniper kills are over 1.5 miles. 

This greatly clarifies the perspective of a 1,000-yard rifle being considered midrange. Furthermore, language in the MRGG program also refers to it as a “sniper support rifle,” which also makes sense if the primary trigger puller on a sniper team is hauling around a .50 BMG or .338 Norma Mag. Other requirements include a 20-inch barrel, a weight of less than 10.5 pounds, and ½ MOA accuracy at 100 yards. 

There were also two rifles being sought: the MRGG-S and MRGG-A. All of the requirements we just listed apply to the MRGG-S, the Sniper (support) variant. While you can certainly buy the bona fide MRGG-S direct from Geissele, it’ll set you back a meager $6,500. With that in mind, we’ve attempted to home brew a rifle that fulfilled the same general specifications and a lower entry cost.

We started with an Aero Precision M5 receiver set and 15-inch handguard. The barrel is a 20-inch Wilson Combat Super Sniper. This fluted 416R barrel features a 1:8 twist and is finished in Wilson’s FDE Armor-Tuff finish to match the custom coating job — more on that below. The low-mass, nickel boron-coated bolt carrier group is also from Wilson, rated for both .308 and 6.5mm Creedmoor. 

The TriggerTech trigger offers an amazingly light, precise two-stage pull. The recoil system is ArmaSpec’s Stealth Recoil System, which is a self-contained drop-in replacement system for the conventional buffer/spring assembly that uses a staged, multi-spring system to soften felt recoil. The main SRS spring is coiled around an operating rod and does not rub on the inside wall of the buffer tube, creating a much quieter recoil action, if that matters to you. The AR-10 version of the SRS is also rated for both .308 and 6.5mm Creedmoor and fits into any standard carbine buffer tube. 

The Victory charging handle and muzzle brake are also of ArmaSpec pedigree. The latter was particularly interesting to us. ArmaSpec has designed what they call the Harmonics Tuner Brake. This otherwise typical muzzle brake features an endcap secured with a single hex screw that can be loosened to adjust the endcap, which ArmaSpec claims will act like a harmonics tuning device. 

The process is very simple, much like zeroing a scope, and is intended to optimize your accuracy by accounting for barrel vibration during firing. The last piece of tuning we added was a Riflespeed gas control system. 

We have, historically, not been particularly fond of adjustable gas blocks on account of them being hard to access, finicky in their adjustments, and quick to carbon lock. Riflespeed addresses all these issues with a large, tactile collar that protrudes from underneath the handguard and makes gas adjustments as easy as literally dialing up or down. Our first test fire of this rifle, with standard fixed gas block, showed some ejector swipes on the spent brass. Riflespeed’s unique and robust system gave us a way to back off the gas flow just enough to optimize ejection while eliminating harsh over-gassing. Particularly with the use of Wilson’s reduced mass bolt carrier. 

We finished off this rig with a bipod from GG&G and an EOTech Vudu 5-25x scope, featuring the Horus TREMOR3 reticle. 

The Vudu 5-25x is a compact, first focal plane scope that quickly gained a reputation for offering a lot of power in a compact footprint. The TR3 reticle offers the same basic “Christmas tree” arrangement of wind dots graduated for distance but with a cleaner sight picture than other Horus designs like the H59. Using a rule of thumb of 2x per hundred yards of target distance, the Vudu 5-25x is plenty of glass to take us to 1,200 yards — well within the capabilities of 6.5 Creed. The scope is seated in EOTech’s factory cantilever mount. 

Finally, we had the whole rifle coated in KG GunKote by P4 Coatings in Tucson, Arizona. We asked for a basic “field paint” pattern with colors biased for our home terrain in southern Arizona. The result is a rattle can appearance that will last longer than hardware store spray paint.

Our final result is a 6.5mm CM gas gun with the same base capabilities of the MRGG at just over half the cost. The low mass BCG, combined with a muzzle and gas system that are both tunable, and a multi-stage recoil buffer, produced an incredibly soft-shooting gas gun that resulted in less disturbance during firing and consistent hits on steel at all ranges tested. It’s not clone correct or SOCOM-issued, but this build offers a less expensive route to 1,200-yard performance with the ease of use that comes with a good gas gun.