Bullpup Your Pump Gun? Bullpup Unlimited – SHOT Show 2017

The Bullpup Unlimited conversion system converts your Remington 870 or Mossberg 500 to a handy bullpup.

For more information, visit https://bullpupunlimited.com/.

To purchase on GunsAmerica.com, click this link: https://www.gunsamerica.com/Search.aspx?T=bullpup%20unlimited.


The bullpup shotgun is one of the hot new guns being introduced by several companies. The reasons are simple and straightforward; they take a hard-hitting gun, reduce the size, all the while increasing maneuverability without giving up reliability or firepower. However, these new generation of shotguns are not inexpensive and most of us already own a pump action shotgun. There are more than 10 million Remington 870 shotgun produced to date, and when you consider how popular the Mossberg 500 is as well, these represent the majority of all pump shotguns in the world.

The system employs an AR-pattern grip and safety system.

The good folks at Bullpup Unlimited have manufactured the BPU-870—which, in its standard LE configuration, is built for 3-inch-chambered 870s with 18.5-inch barrels, six-round magazine tubes and bead-type front sights. (Longer barrels and magazine tubes can be used, but they’ll extend farther out of the kit). This kit reduces the overall length of the shotgun by 10 inches.

The BPU-500 conversion kit fits only 2¾ and 3 inch 12 gauge Mossberg 500 shotguns with plain barrel with bead sights. This kit reduces the overall length of the shotgun by 10 ¼ inches.

The system makes your shotgun of choice a lot shorter and more handy. Image courtesy of manufacturer.


There are several other advantages to the kit in addition to the decreased footprint. They convert the controls to the familiar AR-style grip and safety. They add the ability to customize your shotgun with the rail mounting systems. This means that it effectively converts the most popular shotguns to easily take any accessory that you could mount on a standard accessory rail. The kit also accommodates left-handed shooting with a shell deflector and the position of the buttstock. This problem has always plagued the bullpup design.

Installation of the kit is easy and straightforward by following the instructions and the included tools. All the parts are manufactured from rugged glass-reinforced polymer. There are no permanent modifications to the gun so you can remove the kit and return your gun to its original configuration at any point. MSRP is $359.00 plus shipping and handling for either the Remington 870 or Mossberg 500. They are only available in black.

For more information, visit https://bullpupunlimited.com/.

To purchase on GunsAmerica.com, click this link: https://www.gunsamerica.com/Search.aspx?T=bullpup%20unlimited.

{ 6 comments… add one }
  • Tommy Barrios January 8, 2018, 1:55 pm

    You could not give me any shotgun other than an Ithaca Model 37!
    I have several of them and one of them is the Stakeout (pistol grip handle with 20″ barrel, 8 round capacity (one in the chamber)) which WORKS just fine for me in any situation!
    I’d sell any other shotgun to first person that wanted one, but I’ll stick with my Ithaca 37’s thank you very much!

  • matthew martinez February 27, 2017, 2:11 pm

    All these conversions are good in theory but check out new grip location in relation to the action. looks kind of awkward. id prefer a raptor grip 18 incher or 16 incher (14?) for ergonomics. seems like the bull pup kits are mostly the same. problem is the underslung mag tube. this would work better with a top loading shotgun but the grip is still under or around the barrel or mag tube. either platform is fine i own both but prefer the beefier mossy extraction system of 2 claws. seems a drop in kit always makes a funky gun. imo box fed guns are the best for bull pup anything. (AUGs ak pattern etc.)

  • bmaverick February 27, 2017, 9:44 am

    Back in the day when Dicks Sporting Goods had a sale on the 870, one could buy the 12ga or 20ga for the same price. The wife wanted something to use too without the blasted shoulder recoil, thus we got a 20ga. In hind sight now, there are really no upgrades to the 870-20ga. I’ve been bummed by that for the past 15 years. The 870-20ga is still a remarkable shotgun with the magnum shells shooting slugs taking down deer or with 5-shot coon hunting because they like to eat your chickens. I even made an award for the wife for getting as many coons as I have. LOL
    The Bullpup looks very much like the HALO recon shotgun that my boys play on the game.

  • Will Drider February 26, 2017, 11:51 pm

    Brilliant! I went to the Mfg site and watched the demo fire and the 870 installation vids. Simple and easy. Vid does not show removal of “Stock 870 parts” and does not include the tool to to do those tasks.

    Like many bull pups there is a long trigger bar. How this actually feels, responds (solid, flex, spongy), I could not find any comments. Surely it will be in a review somewhere. It would be good to see demos of tactial and combat loading with the bull pup skin on.

    Overall it looks like an quality, inexpensive upgrade to one you own or a face lift for a cheap pawnshop 870. If you are going to buy a new gun too, total cost will put you near some other designs street prices.

    • matthew martinez February 27, 2017, 2:14 pm

      second on that trigger as these designs extend the actual trigger component and yeah seems ok for a rough pawnshop gun. i used to facelift shotguns all the time with some alumahyde and new fire controls.40 bucks amd maybe a slight barrel chop gets you a “custom” gun.

    • Rev. Ray February 27, 2017, 4:15 pm

      How can anything be considered an ‘inexpensive uprgrade’ when it costs as much as (or more than) the shotgun itself?

      I’ve used shotguns in combat both in the military and law enforcement and never found a need for a bullpup.

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