A tale of conversion: Adaptive Tactic's Sindwinder Venom Kit for Shotguns

Not long ago I tested Adaptive Tactical’s Sidewinder Venom Conversion Kit, products that will switch a tubular magazine shotgun to a box magazine gun on the Mossberg 590. Adaptive Tactical has been in the business for 40 years. They are known for...


The gun is field stripped, followed by gently unscrewing the magazine tube. The Sidewinder Kit tube replaces the Mossberg tube. Mossberg products are known for being rather beefy, which is why the Mossberg 590 series is the king of working shotguns. The Adaptive Tactical magazine tube, which actually holds a piston that cycles when one actuates the slide, is just as robust.

The Mossberg 590 series of shotgun barrels is not interchangeable with the Mossberg 500 series of shotgun barrels. The Mossberg 500 uses a screw at the end of the takedown knob, which is connected to the barrel. The Mossberg 590 uses a barrel loop, similar to many other shotguns. The barrel is secured to the end of the magazine using a magazine cap.

Disassembly of the Mossberg 590 includes drifting the trigger group 10 and removing the trigger group. For users who like to examine their parts as they are removed, remember that pulling the trigger at this point will seriously damage the gun.

I have always liked the way that Mossberg designed their shell stops, which are removable, adding to the end user serviceability of the firearm. In fact, end user serviceability is their second most important selling point to law enforcement. What’s the primary point? Bulletproof reliability.

Once disassembled, one threads the Venom Magazine Tube Assembly into the receiver. If the center line of the magazine aligns vertically when the tube is fully seated, no fitting is required. If it doesn't, one uses the cutting tool to modify the receiver.

I guess it’s time for me to talk a little bit about modifying a firearm. If what is being said in this article is a little too technical or the end-user isn’t 100 percent certain what they are doing, it is wise to stop at “The gun is field stripped…” Removing receiver material using a cutting tool is not undoable.

If anyone is wondering, I found that one can generally restore the shotgun to its original state, in case the gun is repurposed to less lethal or breaching rounds. Having said that, what’s wrong repurposing a box-fed gun to less lethal? There’s nothing wrong with options.

Consider these options: Lightfield’s StarLite less lethal round was designed for distances between 1 to 10 yards. Their MidRange Rubber Slug can do 20 to 40 yards. I have tested both in my Remington 870 and they do exactly what they say they will do. A box magazine gun would be an advantage here.

Once the new magazine tube is installed, the original slide is replaced with Adaptive Tactical’s slide, which dropped right in. Instead of using the magazine tube, a follower assembly, which is really a plunger that is connected to the slide by a keeper key, manually strips rounds from the magazine.

When I tested the assembled gun, I found that Adaptive Tactical uses moving parts made of polymer in the slide to contact the metal parts, which reduces action noise and seems to add to smooth operation. Using the 5-round box magazine, the cycling time was a bit faster. This might be explained by the fact that the piston assembly literally shoveled a fresh round into the carrier.

Shotgun shells fed from a magazine introduce new engineering concepts that do not generally present themselves in metallic cartridges. First, let’s get this out of the way—this setup is designed for 2 3/4-inch shells only. For law enforcement, this restriction isn’t very limiting. However, if this were for hunting, it wouldn't work. There is an optional Kelly grip, which is a protruding handle that screws into one of the three holes in the slide handle. It was designed to add comfort and speed to cycling the gun, especially when using the 10-round rotary magazine. This magazine weighs 21.5 ounces empty, which is enough to be noticeable to the shooter. The Kelly grip is a good idea.

Second, some questions are immediately raised when one looks into shotgun design; 12-gauge bores can vary up to 2 mm. Squeeze any commercial load and the sides will “give” a little. Getting cartridges to feed reliably is a challenge.

How did Adaptive Tactical do it? Using spring loaded feed lips and a very specialized follower, that’s how. Actually, the 10-round rotary magazine uses a roller for a follower that accommodates for any shifting or variances. On the range, the Adaptive Tactical Sidewinder Venom Kit fed smoothly, but the 5-round magazine felt better than the 10-round rotary magazine. Under the force of recoil, the weight of the full magazine torqued it a bit. The Kelly grip compensated for the torque, which means Adaptive Tactical tests their stuff before it’s fielded. Still, any shooter can outrun many autos, and still have rounds to spare, with this setup.

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