One of the best things you can do in the world of NFA items is make a short-barreled shotgun (SBS). The SBS is a slept-on genre of firearm, and it was the first NFA item I ever owned. If you are going to make one, pick a common platform—this means either a Remington 870 or a Mossberg 500/590 series. That way, you can build something truly unique, like the 590A1 “reverse stretch.”
590A1 Reverse Stretch
Nothing touches the AR in terms of modularity, but if you’re looking for something similar, the 590 and 870 offer plenty of options. Once that receiver is serialized as an SBS, you can customize it a ton. Keep in mind that if you permanently alter the configuration, you have to let the ATF know, but temporary alterations are fine.
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My SBS project started when I received a Mossberg 590A1 Compact Cruiser parts kit. The 10.25-inch barrel, the vertical folding foregrip, and the three-round magazine tube were too good to resist. One 590A1 receiver and a Form 1 later, and I had a fairly small and silly platform. Since then, I’ve experimented with different configurations, and my favorite so far is what I’m calling the 590A1 reverse stretch.
What’s a Reverse Stretch?
The term “reverse stretch” traditionally applies to an MP5 configuration—namely, an MP5 that has been chopped into a “K” model. The barrel is cut to the shorter K length, but the receiver remains the full-sized variant.
I’m calling mine the 590A1 reverse stretch because, well, look at it. The stock is actually longer than the barrel. I originally swapped the old-school Retrograde wooden stock onto the gun for a laugh, but the more I shoot it, the more I like it. The importance of a proper length of pull doesn’t disappear just because the barrel gets incredibly short.
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The traditional stock design has always been my go-to for shotguns. Pistol-grip stocks are fine, but I’ll always choose a traditional stock when given the option. The Retrograde stocks have a LOP of about 13.87 inches, which is just perfect for me. The 590A1 reverse stretch turned out to be a rock-solid design that surprised the hell out of me.
Why It Works
The 590A1 reverse stretch gives us an incredibly short barrel and a compact overall length. If you’re indoors, the shorter the gun, the better. Shotguns are close-range weapons, and home defense is a close-range, “two-way” range. Shotguns are a bit like battle-axes: if they land their hit, it’s devastating; if you miss, you’ve wasted a lot of energy.
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This setup is like a boarding axe—smaller, but still devastating up close. The gun is incredibly maneuverable, making it easy to move through my home. While plenty of people deride shotguns for their flaws, no one denies their ability to stop a fight at close range.
The traditional wooden stock turns out to be incredibly comfortable. When we trim the barrel, we get a gun that’s a little lighter, with a bit more recoil and more muzzle rise. Having a solid stock that doesn’t fold or collapse provides a stable surface to meet the meat of my shoulder.
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A cheek weld is always a plus, and you get a great one with this stock. When you mix that with the forward vertical grip, you can achieve an excellent “push-pull” technique. Because the vertical grip on this setup is pushed fairly far back, it makes it easy to maintain a firm grip and push forward. The harder I can push, the more recoil I can mitigate.
I can shoot this thing surprisingly fast for such a small gun. With a standard 18.5-inch pump shotgun, I can fire two rounds of buckshot in about .8 to .9 of a second into an IPSC-sized A-zone. I matched that performance exactly with this super-short reverse stretch.
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The Downsides of the Reverse Stretch
Obviously, downsides exist. The NFA paperwork run-around is always a pain. Beyond that, the short barrel necessitates a short magazine tube. You get three rounds, and that’s it. I might add a plus-one extension later just to reach standard Remington 870 capacity, but for now, three rounds isn’t a lot.
Sourcing 10.25-inch barrels is nearly impossible, and the short magazine tubes and folding grips are equally difficult to find. Attaching lights is also a challenge because you can’t use a standard pump, which is typically the easiest mounting point. It can be done, but it isn’t simple.
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The reverse stretch is a neat idea, but it isn’t exactly practical for the average shooter—unless we can bully Mossberg into mass-producing these parts. That seems doubtful, but hell, we can try.
