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Dual-Action 12 Gauge

Dual-Action 12 Gauge
The TriStar Semi-Auto/Pump Tec 12.

One of the most interesting designs in the world of tactical or home-defense shotguns is the dual-action scattergun which can cycle back-and-forth between semi-automatic and pump-action modes of fire. What’s the advantage of such a design? Tactically speaking, it permits the user to fire specialty ammunition like rubber bullets, beanbags or tear gas shells, which will not normally cycle through a semi-automatic action, by simply switching over to the manual pump-action mode. In semi-auto mode, the advantage is the recoil generated by heavy slug and buckshot loads is somewhat moderated. TriStar’s new and affordable TEC 12 is the latest entry into this unique and intriguing world of dual-action shotguns.

The first successful dual-action model I recall was Franchi’s “Special Purpose Automatic Shotgun” better known as the SPAS-12. The SPAS-12 was a gas-operated and pump-action tactical shotgun that appeared in the late 1970s, marketed intensely to military and police units for the next two decades. There was also a civilian version, renamed the “Sporting Purpose Automatic Shotgun” to avoid United States importation restrictions. Very few SPAS-12s were sold on the civilian market, and those that were command premium collector prices today.

The second, and certainly the most successful dual-action shotgun, has been Benelli’s current M3 model. The secret to the M3’s popularity with military and police forces as well as civilians is the utter reliability of the Benelli inertia drive, semi-automatic system.

The three leading semi-auto shotgun systems are Benelli’s inertia drive, gas and Browning’s long and short recoil systems.
Benelli’s inertia drive system, also referred to as the Montefeltro action, is noted for its simplicity since there are only three moving parts—the bolt body, rotating bolt head and inertia spring. It’s also noted for its speed—no shotgun action is faster—for its cleanliness—it’s not tapping off gas and accumulating carbon—and for its versatility, since it can handle most everything from 2-3/4-inch field loads to 3-1/2-inch magnums. The inertia action also weighs so little that shotguns using it are noted for their lightness and exceptional handling dynamics. Popular Benelli models like the Super Black Eagle and the Montefeltro are famous because of their inertia drives.

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The TEC 12 features the simple and reliable inertia drive. Holt would like a
more substantial operating handle. Atop the receiver is a Picatinny rail.

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In the pump mode, the visible locking lugs (above) of the forearm are disengaged
from the barrel ring. For semi-automatic operation (below), the lugs are seated
in the barrel ring, locking the slide.

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But all good things finally come to an end, including firearm patents. Benelli’s patent on the inertia drive system recently expired, and TriStar was quick to move to incorporate the inertia drive system in their new tactical and home-defense TEC 12.
TriStar is a well-established company offering an extensive line of imported, affordable shotguns.
Currently catalogued are a variety of O/U, semi-auto, pump and specialty models for trap, sporting clays and tactical applications.
If you’ve ever lusted after a Benelli M3, you’re going to love TriStar’s TEC 12, especially for about a third of the price of an M3. When I opened up that TriStar carton, I thought I was looking at an M3—similar controls, similar function, similar features and dimensions.
With its 3-inch chambered, 20-inch barrel mounted with an extended, ported, cylinder choke tube, black pistol grip stock, Picatinny rail, ghost ring sight mated with a winged, fiber optic front sight, military sling swivels and studs, it’s a mean machine. It’s not headed for the grouse coverts. Brought to the civilian marketplace, it’s designed specifically for home-defense and tactical competition, like the 3-gun event.
After unpacking the TEC 12, I suggest the new owner read the owner’s manual from cover-to-cover to fully understand the process of changing back-and-forth from pump to the semi-auto mode. It’s simple, but the key point is the bolt must be closed when doing so, particularly when changing back to the pump mode to insure the rotary bolt is fully engaged.
The changeover process is simple and quick. At the forward end of the pump forearm is a spring-loaded rotary collar mounted with two locking lugs (the manual describes it as the “selector ring”). In the semi-auto mode, the collar is rotated so the lugs are in line with locking seats machined into the barrel ring. With the lugs aligned, you push the forearm forward and let the spring-loaded collar rotate the locking lugs into the barrel ring seats. The pump forearm is now locked in place and de-coupled from the drive.
To switch to the pump mode, you once again rotate the spring-loaded collar, disengaging the forearm locking lugs from the barrel ring, pull back the forearm, cocking the gun and you’re ready to go.
The only quirk I learned is in either the pump or semi-auto mode, the bolt locks open after the last round is fired, and the bolt release button has to be used to close the bolt.

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Lightfield’s slugs are noted for their exceptional accuracy in smooth bores
(above). Federal’s 2-3/4-inch No. 4 buckshot load just pounded the 21×24-inch
target (below) at 35 yards.

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Anyway, the switch is that simple!
As the owner’s manual points out, the pump mode is used for ultra-light or target loads that may not cycle the inertia drive and the semi-auto mode for the heavy stuff—field and magnum loads, slugs and buckshot.
For testing, I first checked the adjustable ghost ring sight for approximate zero by shooting field loads into a target 15 feet away. At that distance, the shot charge makes one large hole in the target and verifies whether or not your point-of-aim/point-of-impact coincide. With credit to the maker, they did. This was done in pump mode, and the TEC 12 functioned just fine with a trigger weight of 5-3/4 pounds.
Thinking in terms of home-defense where 35 yards would be an extreme situation, yet a good distance to check the patterns thrown by the TEC 12 with its cylinder choke, I set my targets at that distance. Switching over to semi-auto mode, I shot Federal’s 2-3/4-inch No. 4 buckshot load and Lightfield Ammunitions’ 2-3/4-inch, 1-1/4-ounce Hybrid EXP sabot slug offhand. The 25-yard black-powder targets I used measure 21×24 inches with a 5-1/2-inch black center bull. At 35 yards, the red fiber optic bead of the TEC 12 fits that 5-1/2-inch bull perfectly, giving you a very accurate sight picture. The targets speak for themselves. The TEC 12 performs, and shooting it offhand, gives you a better picture of how it would perform under field conditions.
The only possible improvements I would make would be to beef-up the operating handle, which is a bit puny and to offer a stock with recoil pads of different thicknesses to enable the owner to adjust the length-of-pull. A pistol grip stock locks you into the set length-of-pull, which on the TEC 12 is 14-1/2 inches. While that length-of-pull is fine in a normally stocked shotgun where you have latitude in the way you position your hands and grip the stock, it’s a bit long for most folks in a pistol grip format, particularly for people of smaller stature.
Overall, I was impressed with TriStar’s TEC 12. It functioned flawlessly when fed the proper ammunition in both pump and semi-auto modes and hammered those targets. Reasonably priced and with a 5-year warranty, it’s a good buy.
By Holt Bodinson

Tec 12
TriStar Arms
1816 Linn St.
North Kansas City, MO 64116
(816) 421-1400
www.gunsmagazine.com/tristar-arms

Action: Inertia semi-auto & manual pump
Caliber: 12 gauge (3-inch)
Capacity: 5+1 (2-3/4-inch shells)
Choke: Benelli-threaded, cylinder, extended, ported
Barrel Length: 20 inches
Overall Length: 43 inches
Length-Of-Pull: 14-1/2 inches
Weight: 7.4 pounds, Finish: Black, Stock: Polymer, pistol grip
Sights: Picatinny rail, ghost-ring adj. rear, winged, fiber optic front
Price: $689

Federal Premium Ammunition
900 Ehlen Dr.
Anoka, MN 55303
(800) 322-2342
www.gunsmagazine.com/federal-premium-ammunition

Lightfield Ammunition Corp.
P.O. Box 163, Adelphia, NJ 07710
(732) 462-9200
www.gunsmagazine.com/lightfield

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