A Full-Auto Remington 1100: The Model 7188 Shotgun

The experimental 12 gauge shotgun was developed for the Navy SEALs during the Vietnam War.

Among the other modifications from a standard Model 1100 were a bayonet mount, an extended magazine tube, and a perforated barrel shroud acting as a heat shield.
Among the other modifications from a standard Model 1100 were a bayonet mount, an extended magazine tube, and a perforated barrel shroud acting as a heat shield.photo from guns.com

So do you think you know Remington shotguns? Here’s one you almost certainly haven’t seen before, let alone handled.

The Remington Model 7188 is a unique, intimidating beast that looks like a semi-auto Remington 870 Trench Gun on the outside. Inside, it was basically gas operated Remington Model 1100 with a modified sear that allowed it to fire in full-auto via a selector switch.

It was specifically designed for use by some of the first U.S. Navy SEALs during the Vietnam War. According to guns.wikia.com, it was liked by the SEALs who got to use it because of the amount of destruction a full-auto 12 gauge could put downrange. But it reportedly kicked like a mule.

Luckily, the folks at the Remington Arms Company in Ilion, New York keep a thorough archive room, with shelves full of something more interesting than old records.

Ben Philippi from guns.com recently got a chance to tour the facility and stumbled upon a great example of a Model 7188 with a walnut stock, distinctive heat shield, and a serial number of 0004.

The story says the Remington 7188 was delivered in 1967 as the Mk 1 with additional modifications, other than the selector switch, requested by the SEALs. This first version was the most common and included the perforated heat shield, extended magazine tube, a bayonet mount, and adjustable rifle sights.

The example Philippi found in the Remington archives looks to be a Mk I judging from the sights and looks to have had it’s trigger group and trigger guard removed.

The subsequent Mk 2 was identical, but used a ventilated barrel rib and front bead sight like a standard shotgun. The Mk 3 was the same, but without the perforated barrel shroud. The Mk 4, Mk 5, Mk 6 had even fewer changes.

Here you can see the serial number, and that the trigger group and selector switch have been removed.
Here you can see the serial number, and that the trigger group and selector switch have been removed.photo from guns.com

“While the SEALs liked the fantastic destructive power of the Model 7188 (especially with the custom loads they tended to use), they found the Model 7188 had one big problem: it was highly-sensitive to dirt and fouling, and this made it quite unsuited for general use in Vietnam. In addition, the enormous recoil of a full-auto burst (even at the low cyclic rate of the Model 7188) was difficult to control, and even with an extended magazine, the ammunition supply was thought to be too small by many SEALs.”

The story says only a couple dozen of each version of the shotgun were ever produced, and they were withdrawn from service after a few years, dubbed a failed experiment from the Unconventional Warfare Devices an Techniques project that developed it.

The fate of most was conversion back to semi-auto fire, designating them Model 7180s.

This photo from thefirearmblog.com of what seems to be a refurbished, customized Remington 7188 with an engraved receiver has it's trigger group and selector switch intact.

A customized version with the trigger and selector switch intact.
A customized version with the trigger and selector switch intact.photo from thefirearmblog.com