The Mossberg Model 6000 Autoloading Shotgun - A Brief History

By Greg Hodnett

Mossberg 6000 in case
Photo by Greg Hodnett.

I recently acquired a twelve gauge autoloading shotgun, the Mossberg 6000. A rare find, the Model 6000 was sold in the late 1980s through the introduction of the Model 9200 (1992). The Model 6000 is a variant, manufactured with parts from its previous generation Model 5500 Mk. II and the next generation autoloader, the Model 9200, which was introduced in 1992.

To understand the Mossberg 6000 autoloading shotgun, one must first look at its mother, the Model 5500. The 5500 series, including the improved 5500 Mk. II "shooting system," promised to be the ultimate upland hunting tool. It boasted two barrels, a standard and a magnum, but could be purchased with only one.

Barrel lengths for this system range from 22 inches to 30 inches in length in civilian offerings, plus military models with 18.5 inch barrels. My Model 6000 came with a 26 inch standard barrel with a 2.75" chamber. This two-barrel system was Mossberg's way of dealing with the myriad of shotshell offerings on the market before the advent of an economically priced autoloader that would consistently cycle both low brass and magnum shells.

It appears that the company gambled that the market would welcome an autoloader that would handle any ammunition, without the compromise of favoring either lighter or heavier fodder to actuate the autoloading function. They must have figured shotgunners would buy such a gun, even if it would mean changing barrels to meet each particular shooting situation.

The Model 5500 came with one standard barrel, for targets shells and standard field loads, and a second barrel for "maximum" (high brass) loads, magnum shells, turkey loads and slugs. The standard barrel featured a larger gas port, allowing lighter ammunition to cycle the action reliably. The magnum barrel, on the other hand, featured a 3" magnum chamber and a smaller gas port, designed for more powerful ammunition, allowing it to cycle shells without damaging the action.

Unfortunately, the model 5500 did not sell as well as expected. Some say it was because of a shorter magazine, holding only four shells. Others speculate it was frustration with having to deal with two barrels. At any rate, slow sales ended the 5500 series.

Closing out the 5500s in favor of a new design (the Model 9200) presented a problem, due to an over-run of 5500 barrels; too many barrels and not enough actions! Mossberg solved this problem with the introduction of a hybrid, the Model 6000. It came about as a practical solution to the above inventory situation.

As the Company phased out the Model 5500 shotgun, they simply paired Model 9200 actions with Model 5500 barrels. Voila, the Model 6000 was born! In the early 1990s, Mossberg closed out their Model 6000 shotguns, ending the era of the two-barrel shooting system for their autoloading shotguns.

Thanks to Victor and Cheryl Havlin, at Havlin Sales and Service, I was able to purchase what I believe to be one of the only remaining "as new" Model 6000 shotguns on earth. The Havlins manage a treasure trove of Mossberg memorabilia, parts, information and classic guns.

In addition to what is now my favorite shotgun, I was also able to buy one of the last new, unfired 24" magnum barrels on the planet at a very reasonable price. While I was at it, I could not resist purchasing a classic Mossberg two-barrel hard case along with a few accessories, including a couple of extra choke tubes. I keep an old-style knurled Mossberg 500 full choke tube in each barrel of my Model 6000 while the gun is stored.

My Model 6000 shooting system boasts its original 26" beaded barrel, a 24 inch real-tree magnum barrel with Mossberg fiber-optics, eleven choke tubes (eight of which are classic Mossberg tubes) and a two barrel take-down hard case.

This gun is a hoot to shoot. I have fired about 400 rounds through it, so far. It is custom fitted, which doubles its value to me. My 6000 has proven to be very a handy and reliable gun for birds, squirrels and clays with the 26 inch barrel. I do not shoot skeet, but I would not hesitate to do so. Trap is another story. The 26 inch barrel is barely long enough for a decent sighting plane and the spent hulls fly in the face of the opponent to the right of the shooter.

Full disclosure mandates that I admit certain extremely light reloaded shells did not cycle in my Model 6000. These were 7/8 ounce loads using Red Dot powder, at less than 1165 fps. The same load at velocities above 1300 fps cycles just fine. This includes international 24 gram shells.

For one ounce loads, velocities above 1250 work best and slower powders allow for lower velocity loads that cycle reliably. Every store-bought one ounce shell I have tried worked fine. I have fired four different brands of store-bought shells, as well as numerous handloads from 7/8 ounce to 1-1/8 ounce of lead in the standard barrel and very heavy 1-7/8 ounce lead loads through the magnum barrel.

Speaking of the 24 inch magnum barrel, I was able to place slugs right up the middle with a cylinder bore tube. My Mossberg turkey choke (or Hastings super-full) in the same barrel will easily pepper a turkey neck with lots of #5 pellets, and even more #6s, at 35-40 yards.

I like my Mossberg 6000 so much that I sold three shotguns and passed down three others in its favor. At present, my Model 6000 is the only 12 gauge gun I own. I kept my antique Savage .22/.410 O/U combination gun for sentimental reasons (and because sometimes you just have to have a small bore gun for a certain type of fun). When it comes to serious shooting, the Mossberg 6000 is a gem.

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Copyright 2017 by Greg Hodnett and All rights reserved.