The Evolution of the Modern Carbine: Reviewing Two Generations of the American Defense MFG UIC Mod 2

Cloning My Most Accurate AR-15 Build

My History With The ADM UIC Mod 2

Have you ever sold a rifle and instantly regretted it? My 2016 American Defense Manufacturing UIC Mod 2 definitely fit the bill on that front. Featuring a Flat Dark Earth Cerakote finish, a Criterion 16” Mid-length chrome lined barrel, and a host of other upgraded components, that carbine proved to be far and away the most accurate gas gun I ever owned.

Any time I loaded up that handy carbine with 69gr. Sierra MatchKing handloads, it proceeded to stack rounds atop one another with boringly consistent precision. Don’t just take my word for it though, I’ve got some video evidence of that UIC upper receiver repeatedly punching bug holes to prove it!

One of they joys of putting together a small business is the hunt for initial startup capital. When I founded Precision Rifle Components, liquid capital happened to be in short supply, so in order to raise some funds I wound up liquidating a portion of my personal firearm collection. The aforementioned Flat Dark Earth UIC found an excellent home with one of my good friends, but the loss of that tack-driving rifle has haunted me for years.

A couple months back I was chatting with Jeremy Kattner of ADM about that rifle, and all of the updates that have been made to the UIC platform over the past five years. The list of features and component updates were pretty remarkable, but I stubbornly wanted to clone my original rifle.

Jeremy paused, pondering that request for a minute, and said he’d follow up with me in the next couple days. After some digging around parts bins filled with discontinued inventory, past demo rifle components, and a handful of cosmetic blemished items, he managed to successfully piece together a complete “clone-correct” rifle to match the one I had purchased a half decade prior!

The icing on top of the cake was the matched upper and lower receiver set he managed to track down. Jeremy pulled the vintage ADM lower receiver out of its packaging and asked me if I noticed anything unique about it. Apparently they had stashed this one away in inventory on the occasion that one of their Marine buddies wanted a custom rifle built out.

I eyeballed the receiver a bit, turned it over in my hands, scanned the engraved company name, city of manufacture (New Berlin, WI), the caliber, and then the serial number, when my eyes popped wide open. Engraved just above the safety selector were the numbers “0311”:.

For you non-jarheads out there, the number 0311 is synonymous with the Military Occupation Specialty (MOS) of a Rifleman (My old MOS!) I immediately pulled out my credit card and offered to buy that rifle on the spot.

Jeremy took the receiver back, repackaged it, and discussed the build specs of this rifle (versus what is currently included in their new production UIC’s). While my original intent was to clone my old rifle, the nature of the USMC serial number inspired me to select an OD Green Cerakote finish instead.

But enough with the backstory of this particular rifle, let’s dig into the guts of the American Defense MFG UIC Mod 2 – Past and present!


Upper Receiver Parts of ADM’s Universal Improved Carbine

The lower receiver may contain most of the AR-15’s fire control group, but the upper receiver contains most of the subassemblies tied to a rifle’s inherent accuracy potential. What components are used in an upper receiver will play a big part in how it performs, but how they’re assembled is equally important! ADM manufactures their billet receivers 100% in-house, a process that very few manufacturers handle internally. Their Premium Bolt Carrier Groups feature a black nitride finish sized to the latest Mil-Spec TDP, and are extraordinarily easy to clean.


adm chrome lined barrel

Criterion chrome lined barrel on an ADM UIC Mod 2

The original UIC Mod 2 (2014-2015 production) featured a chrome lined barrel manufactured by Wilson Arms. By the time my original rifle had entered production, ADM migrated suppliers from Wilson to Criterion Barrels. Featuring a custom lightweight profile, these barrels were machined from 4150 CMV steel with a salt bath nitride finish. My original UIC (and the newly produced replacement), featured Criterion’s 16” mid-length Hybrid Contour barrel, with a chrome lined bore and a .223 Wylde chamber. Featuring a hand-lapped bore, Criterion manufactures the world’s only true “Match-Grade” chrome lined barrel.

These days ADM’s UIC Mod 2 comes standard with a barrel featuring the same length and profile as both of my rifle builds, but continues to feature a salt bath nitride finish rather than the chrome-lined option I had previously selected.


Muzzle Device


The ADM UIC Mod 2 comes standard with a SureFire Warcomp Flash Hider

The original UIC Mod 2 came standard with Griffin Armament’s Flash Comp muzzle device. My initial build featured their Taper Mount Two Port Brake, as I regularly used it as a RECCE-7 suppressor host. These days the UIC Mod 2 comes pre-equipped with a SureFire Warcomp, a design that offers a 50/50 muzzle brake flash hider and ported compensator that offers cross-compatibility with SureFire’s SOCOM suppressor line.




Side-by-side shot of Gen 1 and Gen 2 ADM MLOK Handguards

My original rifle and clone build incorporated ADM’s legacy Gen 1 MLOK handguard design, featuring two clamping screws that engaged with an aluminum barrel nut. While I had never encountered any loosening or movement issues between the barrel nut and handguard with those initial builds, ADM successfully redesigned their handguard interface system in their Gen 2 MLOK handguard models, which now feature two clamping screws, an anti-walk screw, and an integral anti-rotation pin.


Gas System

Early model UIC’s included a proprietary HD gas system designed to mitigate recoil impulse to a point where a mid-length gas system felt more in line with what you would expect out of a rifle length gas system setup. The only downside to this design, is that it was designed specifically for use with the UIC platform and subassemblies. As many people have a tendency to swap out components with a variety of aftermarket components, ADM switched out the gas system to a standard mil-spec design intended to function with a full spectrum of gas blocks (the UIC Mod 2 comes with a fixed .750 gas block design, while the Competition model comes standard with an adjustable gas block), bolt carrier groups, and buffer assemblies. By the time my 2016 build had been constructed, ADM had already switched over to the standard gas system design, so I can’t really offer an honest firsthand point of comparison between the two.


Charging Handle


Pictured is a Radian Raptor charging handle installed on a UIC Mod 2.

My original 2016 UIC arrived with a BCM Gunfighter ambidextrous charging handle, but ADM migrated to the Radian Raptor charging handle shortly afterward. I have a handful of rifles featuring both models, and while I prefer the Radian Raptor for its ability to minimize gas blowback when shooting suppressed (particularly with the -SD models), I prefer the ergonomics of the BCM design (they’re also a local Wisconsin company, so I elected to go this route with my clone build). Your mileage may vary on this one, but you can’t really go wrong with either option. Both are great reliable designs with an established track record of success.


Lower Receiver Parts of ADM’s Universal Improved Carbine

While the Upper Receiver may be the focal point for inherent accuracy, the lower receiver group is central to the actual user interface. Ergonomics, trigger control, and weapon fitment are all key elements of lower receiver design. If you haven’t taken the opportunity to handle a UIC carbine, I’d highly recommend exploring the unique elements of its design. Once you get used to the intuitive nature of the geometry and controls, you’ll have a hard time wanting to revert back to the plain jane AR-15 lower receiver design!

Lower Receiver


All ADM rifles come standard with fully ambidextrous controls.

When you pick up an ADM UIC, the first thing you’ll notice is the lower receiver design. One of a select few brands that offer a truly ambidextrous experience, the UIC Mod 2 provides a handy and ergonomic setup for southpaws and righties alike.

Over the past few years there have been a handful of design improvements to the UIC lower receiver, including trigger guard geometry updates, mag well geometry changes (from P-Mag style sides to a triangular layout), and a switch from spring pins to set screws for the ambidextrous controls, the overall function of the lower has remained fairly consistent over the years.

All UIC lowers are machined from 7075-T6 aluminum billet with Type III Teflon-infused hardcoat anodized finish. The centerpiece of this design are the unique controls, including a truly ambidextrous magazine release, and an ambidextrous bolt catch (which is extremely handy for righties when shooting from the prone position).

An extreme level of attention to detail has been applied to the overall design of the UIC lower receivers, including extremely subtle features like chamfered edges and flared magazine wells.




Each ADM UIC Mod 2 features a Geissele Two-Stage G2S trigger.

The old adage “If you can’t beat them, join them” comes to mind with ADM’s UIC trigger selection. All ADM rifles come standard with a Geissele G2S Two Stage trigger installed. Geissele has long held the mantle as the firearm industry’s pre-eminent AR-15 trigger manufacturer, so a quality rifle design like the UIC Mod 2 pairs perfectly with a premium trigger like the G2S.

There was a time when ADM produced their own trigger design for early model UIC’s, but with the competitive price point of the G2S and its stellar reputation as an excellent match-grade trigger, ADM elected to switch over to the Geissele design in 2016.


Another subassembly that ADM elected to outsource in 2016, all UIC Mod 2’s come standard with Radian’s Talon ambidextrous safety selector. ADM produces their own ambidextrous safety design, but demand for a more tactile and pronounced engagement surface has increased over the past few years, so user preference has gravitated toward the Radian design. I generally prefer a slightly less pronounced safety layout, so I asked Jeremy to include the classic ADM safety set on my retro UIC Mod 2 clone.

Stock and Grip

ADM originally included a B5 Systems SOPMOD-Bravo stock during the initial run of the UIC rifle line, switching over to the Magpul SL in 2016. Pistol grip selection shifted from the Magpul MOE+ to the MOE around a similar timeframe (the former includes a slightly more tactile rubberized gripping surface, but it tends to accumulate dirt and carbon quite a bit more than its polymer counterpart).

 Buffer Assembly


Side-by-side comparison between a standard mil-spec buffer tube and ADM’s Reliability Enhancing HD Buffer Tube

The buffer system plays a huge role in how a rifle shoots and feels to its operator, and quite a bit of engineering has gone into the design of the UIC Mod 2 over the years. Original UIC Mod 2’s were sold with a standard mil-spec buffer tube and castle nut, along with ADM’s Reliability Enhancing HD Buffer.

The HD buffer finish has been updated over the past five years (it now comes standard with a black nitride finish), but the overall design of the assembly remains true to its original design. Machined from stainless steel, ADM buffers weigh in at 4.4 ounces, approximately the same weight as an H2 carbine buffer, with a series of non-reciprocal weights that impact in a staggered sequence. This helps reduce bolt bounce, and serves to create a much smoother recoil impulse when paired with a standard Mil-Spec carbine buffer spring.

This buffer is paired with ADM’s Enhanced 10-Position Buffer Tube, offering four additional length adjustments when compared to a mil-spec buffer tube design. ADM’s buffer tube is locked in place with their Light Weight Castle Nut, which they recommend attaching to their QD end plate with VC-3 Vibratite rather than the traditional staking operation.

Custom Built Carbines: Order Your Own!


Sending a few rounds downrange at Precision Rifle Putt-Putt

After a side-by-side inspection of my new (old?) UIC carbine alongside one of their brand new UIC models, it’s clear that American Defense MFG is committed to the continuous improvement of the AR-15 rifle platform. I’m looking forward to keeping tabs on future design improvements, and may consider adding another UIC Mod 2 to the collection down the road!

If you’re looking for a premium carbine design with fully-ambidextrous controls, you can’t go wrong with a rifle build from ADM. If you have any questions about customizable options and component selection, feel free to give them a call at (262) 780-9831, or via email at After my experience custom-building a carbine to my relatively unique specifications, I’m pretty sure they can put something special together for you too!

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