Imagine a Remington 1100 shotgun in full auto.  Yes, pretty sweet.  The US Navy SEALs tried them out in Vietnam.  They found the recoil rather… punishing.  Even with good technique in firing them.   With #4 buckshot (at 27 pellets per round) that’s a whole lot of projectiles flying downrange with a cyclic rate of 420 rounds per minute.

At the same time, sans a muzzle brake, the recoil would no doubt be brutal.

Before I had a tragic boating accident, I had what was effectively the semi-automatic version of this gun.  Thanks to some magic by a master gunsmith, including a muzzle brake, shooting 3″ magnums was no big deal.  In fact, one could almost get close to three good hits on a target in under a second.  And still hold the gun, and be willing to shoot the sequence again, all without needing an icepack for your shoulder.

Contrast that with a 3″ magnum out of a Mossberg 590…  I almost dropped the gun after pulling the trigger.  I won’t do that again unless I’m looking at a 600 pound bear charging at me.  And even then I’d have to weigh my options.

From GunWiki:

The 7188 was specifically developed for U.S. Navy SEALs for use in the Vietnam War. It was well-liked by the SEALs because of its sheer destructive power, but was said to recoil extremely hard. After the war, most 7188s were converted to semi-automatic operation and designated the Model 7180, despite retaining the unique selector switch…

The 7188 had many variants, in fact, six.

Mk 1

It had an extended magazine, perforated barrel shroud, bayonet mount and adjustable rifle sights. This is the most common version.

Mk 2

This was identical to the Mk 1, but had a ventilated barrel rib and front bead sights of a standard shotgun.

Mk 3

It was identical to the Mk 1, but lacked the perforated barrel shroud.

Mk 4

This was a Mk 3 with standard shotgun sights.

Mk 5

This was a Mk 1 with no perforated barrel ribs and lacked an extended magazine.

Mk 6

This was a Mk 5 with standard shotgun sights.

Bonus time:  Here’s the book on Remington shotguns.  Including how to make your 11oo select fire.  For educational purposes only, of course.