August 09, 2018
By G&A Staff
While pump shotguns have been serving in a defensive role for decades, their Achilles heel has been the inevitably slow reload when compared to other platforms that feature a detachable magazine (DM). Feeding one round at a time into a tubular magazine is slower and requires some dexterity that may be unavailable in a stressful situation for some folks. For some of us, shotgun reloads can be timed with a sundial - until now.
Remington's new 870 DM pairs a detachable box magazine with the iconic and time-tested 870 shotgun. (Since 1950, more than 11 million have been manufactured.) Now with a detachable mag, the 870 shotgun is an even stronger selection for defense.
Changing the feeding system on a reliable-as-a-hammer shotgun could be disastrous. A fast reload isn't worth the effort if it leads to inducing a malfunction that has to be cleared before the shotgun can fire.
When Guns & Ammo first saw and fired the 870 DM, we asked Daniel Cox, Remington's shotgun product manager, what type of testing they did to make sure the new feeding system was as reliable as the old.
"We took 100 of these new shotguns, put 2,000 rounds through each of them, and recorded every issue that came up," Cox said. "That gave us a large sample size with a lot of rounds on each sample. We did the same thing with the legacy 870. The failure rate on the regular 870 was less than 1 percent. The 870 DM's failure rate was even smaller. We didn't think we could do it, but the 870 DM feeds more reliably than the original 870."
The results of the testing are pretty impressive, but a closer look at the shotgun reveals how they achieved such an improvement.
A classic 870 utilizes an elevator to lift a shell from the tubular magazine and move it up in front of the bolt. Pushing the slide forward forces the bolt to scoop the shell into the chamber. If history is any indicator, this is a very effective and reliable way to feed a shotgun.
The 870 DM's magazine presents the shotgun shells from a fixed position inside the receiver. The elevator is now gone and the static magazine replaces it. Anytime nonmoving parts replace moving parts, reliability stands a good chance of improving.
Fitting a detachable magazine to the 870 required more than plugging the tubular magazine. (In fact, the hollow tube is still there to allow the forend to slide.) The forward trigger pin needed to be enlarged to support the magazine well, while the bolt also required modification.
The bolt on a standard 870 features a flat bottom. When loading, the lifter comes up and the bolt comes forward. When the bolt face is approximately 11/2 inches from the chamber, the elevator drops down and leaves the shell unsupported. This hasn't been a big issue for Remington given that the system has worked for a very long time.
The 870 DM's bolt has a lug fitted to the bolt face that extends approximately .42-inch down towards the magazine. During the feeding cycle, the magazine follower maintains constant upward pressure on the incoming round while the lug from the bolt face scoops it out of the magazine and the bolt stuffs it in the chamber. The 870 DM's feeding arrangement maintains constant pressure from two directions (the bolt face at its rear and the magazine spring from beneath), leaving the shell no place to go but into the chamber. This is why we feel it is a genuine improvement over the traditional 870's action.
Each 870 DM Magpul ships with one, six-round magazine. The top of the magazine positioned inside the receiver is steel, while the lower mag body is polymer. After testing, Remington concluded that variations in shotshell dimensions made putting any more than six in the box problematic. Development continues to see if a reliable 10-round magazine is possible.
The magazine slides straight up into the receiver and the magazine catch engages the front of the stamped steel. Releasing the magazine requires pressing the large lever at the front of the magazine well. Empty magazines do not drop free, but there is plenty of magazine body to pull on.
The magazine well is made from aluminum and attaches to the receiver by means of two large pins that screw into place. High-volume shooters that practice reloads a lot will likely experience some wear and tear to the magazine well as the steel upper on the magazine slams into the aluminum well. However, all that's required to replace a beat-up mag well is to remove the two pins, drop the old mag well and screw a new one into place. The job takes 2 minutes if you take your time.
Sights get defensive.
Besides the removable magazine, the two 870 DM samples G&A were sent for testing came with many features ideally suited for a defensive role. We especially liked the XS Ghost-Ring rear sight and base with a white bead up front. Traditional bead sights are difficult to use with slugs and become invisible in low light. The steel base is a Picatinny rail that runs the length of the receiver and is secured to the 870 receiver by four screws.
The sights work well with everything from birdshot to slugs and the Pica-tinny rail on the base makes attaching an appropriate optic a snap. Having sighting options on a shotgun still seems like a relatively new concept for some, but putting a red dot sight on this shotgun is an excellent idea. The Magpul stock and forend complete the package.
The Magpul stock and its adjustable comb height makes the shotgun shootable in a red dot configuration. Putting any type of sight on a shotgun pulls the shooter's head off the comb because every shotgun stock is designed around a bead or vent-rib sight, which plants the shooter's head firmly on the comb. Lifting the sights off the barrel not only pulls one's head up off the comb, but it gives recoil a running start into the shooter's face. Magpul's 870 DM Magpul adjustable stock uses spacers to raise the comb enough that the shooter can still have a firm cheekweld even with an optic mounted.
The Magpul SGA stock also accommodates several sling mounting options. It has a spacer-adjustable length of pull, as well. The forend features tabs at the front and the back to keep the support hand in place for pumping, and M-Lok cutouts for adding lights or aiming lasers.
The barrel's muzzle is threaded for choke tubes and the 870 DM arrived with a tactical extended Cylinder choke. The "extended" Cylinder tube allows the choke tube to host a muzzlebrake and gives the muzzle some standoff should you want to use this shotgun for doing things like breaching doors. We can't imagine that many will, but it can benefit everyone.
The 870 pump-action shotgun has often been regarded as the ultimate home-defense platform. The new Remington 870 DM could succeed that reputation in filling such a role. When viewed as a package, the 870 DM Magpul also represents an incredible value. It is a well-thought-out package that brings improved reliability and faster reloads to an already time-tested firearm that has been defending American homesteads for more than 60 years.
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