Guns Box Mag Fed Shotguns: Sorting Out Scatterguns Iain Harrison February 25, 2022 4 Comments, Join the Conversation Box magazine fed shotguns suck. There, we said it. Having used them off and on for the past decade in three-gun competition, we can confidently say that, even in their most highly tuned and massaged state, a box mag fed shotgun doesn't achieve anywhere near the reliability of say, a Benelli M2. Which is not to say they don’t have their place. If you enjoy practicing stoppage drills and wincing every time you drop $150 worth of tuned, big-stick mag in the dirt, then they’re just what the doctor ordered. If you happen to own one that’s moderately reliable, then the advantage gained from being able to jam 15 rounds into the gun in a couple of seconds might — just — be worth the tradeoff in a long field stage. And if you’re one of those people who claim, “My XYZ blastomatic has never missed a beat,” well, you just don’t shoot that much, do you? As you can probably tell, we’ve got a love/hate relationship with these things ever since buying our first Saiga 12 in 2005, and we’ve been searching ever since for a shotgun that feeds reliably from cheap high-caps and doesn’t beat itself to death in a few thousand rounds. This is a tall order, as from an engineering perspective, there are a lot of hurdles to overcome. A shotshell’s rim, designed to work in break-action guns, complicates matters when stuffed into a box magazine — the blunt, tubular shape of your typical 12-gauge ammo looks nothing like the profile of a sleek, tapered rifle round. To add insult to injury, it’s forward weighted with next to nothing to balance out that ounce of lead up front. As icing on the cake, there’s not much in the way of gas pressure or volume in order to work a semi-auto action, so we’re already way behind the eight-ball. Do any of the candidates in the following pages have what it takes to overcome these challenges? Read on and find out. JTS M12AR-B1 Looking like an AR-10 with a prescription for HGH, this Chinese-made shotgun accepts AR fire control components and have a manual of arms immediately familiar to 99 percent of our readership. It uses a short-stroke gas piston operating system with a gas port located about 5 inches from the breech face, and the op rod’s tail impacts a toweringly tall extension on its bolt carrier group. The carrier itself is an odd amalgamation of AR-ish design features, but uses a bolt with a separate head in front of the multi-lug locking piece. This floating head houses a comparatively small extractor located across from two projections that control the round as it’s fed from the box magazine. Bolt unlocking is achieved via the usual helical cam path, but the engineers at the Chongong Jianshe Industry Group have gave this baby a significantly longer delay before the bolt turns, presumably due to the gas port’s location initiating the unlocking sequence earlier than on a comparable centerfire rifle. As shotshell primers are noticeably softer than their 7.62 counterparts, its firing pin is spring loaded to avoid the entertainment potential of a slam fire, and the lower part of the BCG is contoured to slide over the top round in a magazine. The reason for that tall carrier extension is evident when you strip the gas system — in order to make use of the low pressures generated by all ammo types, the floating piston measures 0.86 inches in diameter and, to accommodate it, the gas cylinder is proportionately enormous. The M12AR proved to be surprisingly reliable, gobbling up all manner of Wally World bulk pack ammo, once the gas plug was turned to the largest setting. Recoil was soft, with a noticeable hitch in its giddy up as the carrier reached the point at which it began to unlock. It’s not distracting, but you’ll recognize it if you switch from one autoloader to another. The downside is a lack of mags with anything greater than a 5-round capacity, which puts it out of contention for serious consideration. JTS Group M12AR-B1 Overall Length:38 inchesWeight: 8.5 poundsMag Capacities: 5Reliability: 4/5MSRP: $600URL: jtsgroup.us Typhoon F12 The Typhoon Defence Industries F12 has an overall feel of heft and quality to its design and construction. It’s nicely machined and contoured — lines match up where the upper and lower receivers meet, and there’s no gaps between the major components. Color accents and a flat-faced trigger indicate that it’s targeting the racing crowd, and it’s one of the few we received with both five- and nine-round magazines. The gun itself is sourced from the Turkish company Derya Arms, which means it’s a derivative of the Derya 12 — a firearm imported to both Canadian and European markets for the past few years, it’s gained quite the following. While its overall appearance is reminiscent of an AR, once you delve beneath its skin there are a lot of features that let you know it’s been designed from the outset as a 12 gauge. Take its gas system, for example. It’s a lot like the short stroke layout found on a sporting shotgun from Winchester or Remington, in which an annular piston acts against a drive collar, which in turn pushes twin operating rods connected to a bolt carrier. The carrier locks and unlocks the bolt’s single lug which engages a cutout in the barrel extension. Unlike its tube-fed counterparts that wrap their pistons around the magazine tube, the F12 simply makes use of the barrel’s exterior, chromed to make cleanup easier. In order to accommodate shells of different charge weights and payloads, a reversible collar permits more or less gas to blow by the piston. At the range, we found it had a distinct preference for quality ammo — Aguila ounce-and-one-eighth loads at around 1,200 fps were our go-to, as cheapo bulk pack fodder lacked enough gas to work the action. Once the right shells were jammed into its nine round magazines, it chugged along without complaint. We tried using extended mags from our custom Firebird Precision Akdal, as well as those from Tooth & Nail Armory — both fit and functioned just fine. Typhoon Defence Industries F12 Overall Length: 37 inchesWeight: 8.7 poundsMag Capacities: 5 and 9 standard, up to 20 aftermarketReliability: 4/5MSRP: $600URL: typhoondefense.com UTAS XTR-12 Perhaps the most AR-ish shotgun of the lot is another Turkish design, this one from UTAS, which utilizes a DPMS Gen 1 pattern lower. It’s machined from billet, offers ambi controls, is nicely finished in gray Cerakote, and offers the option of using one receiver for both rifle and shotgun. Its 11-inch handguard houses a short-stroke piston gas system, which is non-adjustable at the user level. In fact, just to get access to it requires the removal of four metric Allen head screws in order to pull the handguard. Once that’s off, you then have to unscrew the gas plug (another Allen wrench) before accessing the short piston and operating rod. Rather than use a large piston to make best use of the small amount of gas available, the manufacturer went for a truly cavernous gas port located a couple of inches ahead of the chamber. This is drilled at an angle, no doubt to mitigate the quantity of plastic crap blown off the wadding as it passes. Its piston impinges the op rod, which in turn contacts a buttress on the bolt carrier, which will no doubt give a case of déjà vu to anyone who’s used a piston AR. The bolt carrier group looks almost exactly like an AR-10’s, only scaled up to use 12-gauge shells and missing its ejector (there’s a fixed ejector located in the left side receiver wall). Being so much like an AR-pattern rifle, we had high hopes for the XTR-12, as having a common manual of arms, look, and feel would make transitioning from rifle to shotgun that much easier and more familiar. Unfortunately, in our testing it wouldn’t get through a full magazine without a failure to feed, no matter what tasty morsel we offered. It would seem that in order to cycle at all with its tiny gas piston, the buffer spring has been made too light to reliably strip rounds from the mag. Bummer. Cannot recommend. UTAS XTR-12 Overall length: 38 inchesWeight: 7.3 poundsMag capacities: 5 and 10Reliability: 1/5MSRP: $1,100URL: www.utas-usa.com JTS M12AK We reviewed the Molot Vepr 12 way back in, appropriately enough, issue 12, and concluded that it’s a better shotgun than the Russian Saiga 12 it was based on. Now that both Molot and Saiga are subject to sanctions due to the Russian invasion of Crimea, the availability of both is limited to whatever is in the current supply chain — which in the case of the Saiga is bugger all. Enter the Chinese. Like its AR-based brother above, the M12AK is imported by the JTS Group in Rochester, New York, and retailed through your local Academy Sports store. The sample we received features an RPK trunion, (before you ask, it’s cast, rather than forged), hinged top cover with Pic rail, and four-position gas plug. It has the RPK’s thicker receiver walls, which should contribute to longevity. We say, “should,” as the Vepr featured in issue 12 has since retired after four hard seasons on the three-gun circuit after beating its rear trunnion rivets to oblivion. Like its Russian counterpart, the M12AK includes a plastic magwell, making magazine changes much easier than on the earlier Saigas, though it does mean that the MD Arms 20-round drum can’t be used (if you can even find one). Mags with a greater capacity than the five-rounders included in the box can be sourced from SGM Tactical in Knoxville, Tennessee, or if you really want to push the boat out, then Dissident Arms will gladly sell you a 20-rounder that will serve as a handy monopod for those tricky standing slug shots. There are a couple of notable departures from the Vepr blueprints, however, as the M12AK doesn’t include the former’s polymer bolt buffer and uses a modified op rod that attaches to the carrier closer to the bolt itself. The gas piston (or puck) is aggressively cut to provide sharp, scraping surfaces in order to rid the cylinder of plastic fouling, which should enhance reliability, and the barrel is internally threaded for choke tubes, rather than the external thread pattern of the Russian guns. Overall, the execution is a bit rough. There are plenty of machining marks evident on the bolt face and fire control group, and the exterior metal has a basic, industrial black oxide finish which rusts as soon as you lay a sweaty hand on it. But at the price point, there’s plenty of room to upgrade as funds permit, and there’s enough in the way of existing aftermarket support to go hog wild, should your heart desire. JTS Group M12AK Overall length: 39.5 inches Weight: 9.1 poundsMag Capacities: 5 standard, up to 20 aftermarketReliability: 4/5MSRP: $450URL: jtsgroup.us Genesis Arms Gen-12 While every one of the foreign-made examples above use some type of short-stroke gas piston to eject and load, Genesis Arms employs some American ingenuity to adapt the inertia operating system found in Benelli and Breda shotguns. The result is comparatively light and fast-handling, while retaining AR architecture as much as possible and being adaptable to the wide variety of shotgun ammo via means of changing buffer weights. Like the UTAS, it uses a DPMS Gen 1 pattern lower, so you can buy a complete GEN-12 gun or just the upper, magazines, and a retrofit kit with a few tweaked and strengthened parts for your own lower. The sample we received for evaluation was a preproduction version with a two-digit serial number, but in terms of overall design and execution, it seemed ready for prime time. Up front, a 13-inch M-Lok handguard covered an 18-inch barrel with external, Saiga-style threading for choke tubes, while the upper receiver seemed comparatively svelte when stood next to the JTS M12AR. With the exception of a right-side charging handle, the rest of the gun is vanilla AR, and it’s not until you venture to strip it that evidence of the operating system comes into play. On punching the takedown pins on the lower, the heavily spring-loaded BCG is immediately noticeable, as it pushes back against the comparatively stiff buffer spring. The two fight each other for supremacy during the firing cycle and the subsequent back and forth allows the 10-lug bolt to unlock. Yes, 10 — we had to use both hands to count them. In order to adapt an AR bolt carrier to inertia operation, the engineers at Genesis Arms implemented some fairly extensive modifications. The gas key or piston impact lug is gone, and the area housing the firing pin has been lightened, while the cam pin is rounded where it contacts the upper receiver. The corresponding mating surface in the upper has been treated to a steel insert, much like the Colt 901, in order to handle the loads placed on it. The inertia operating system has a number of inherent benefits. In tube-fed shotguns, it has an enviable reputation for reliability and longevity, and we expect these to carry over to a box-fed version — as there’s no gas piston, the gun runs cleaner and there are fewer parts to wear out or break. These benefits don’t come without a downside, however, and while gassers spread their recoil impulse out over a longer time span, inertia guns dish it out it good and hard. In order to assess all the guns in this article side by side, and with multiple shooters, we arranged several range trips and each time, the GEN-12 was the shotgun that wound up with the least number of rounds through it. Even though it was one of the few models that would function reliably with reduced loads, when offered a second or third opportunity to run the gun, the reply was always, “[email protected] no! That thing kicks like a mule.” While five-round mags are currently available, according to the company they’re currently beavering away, perfecting the geometry of a 10-round version for later this year and a coupler to join two mags for twice the capacity next year. Genesis Arms GEN-12 Overall Length: 35 inchesWeight: 7.75 poundsMag Capacities: 5, 10Reliability: 5/5MSRP: $2,230 for complete gun, $1,550 for upper onlyURL: genesisarms.com [Photos By Kenda Lenseigne.] More on Shotguns Shotgun Shell Holder Guide: Feeding the Beast.Meet the Fabarms STF 12 Tactical Shotgun.Speaking of, here's our list of Tactical Shotguns for Self Defense.The Remington V3 Tac 13: DIY Shotgun Improvements.Shotguns for Self Defense in a Crisis. Explore RECOILweb:House Representatives Unveil Universal Background Check BillPossible Executive Action on Gun Control coming after holidaysShe's nearly a century old - No1 Mk 3 Lee Enfield on the rangeSHOT16: Ashbury Precision Builds APO Cheytac for 4K Yard Shot NEXT STEP: Download Your Free Target Pack from RECOILFor years, RECOIL magazine has treated its readers to a full-size (sometimes full color!) shooting target tucked into each big issue. 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