Bushmaster Arm Pistol

Back in the 70s, this was originally the Individual Multi-Purpose weapon or IMP. It was chambered in .221 fireball and was designed for the airforce. A PDW for pilots. It was designed to be shot from the arm, but they also did consider shooting it from a sling. Similar to SAS technique, the shooter would press out and the tension from the sling would stable the firearm.

Bushmaster Arm Pistol

Bushmaster took the design and chambered it in .556. It is gas piston driven. Barrel length is 11.5″ weighs 4.25 lbs. OAL 20 inches. Retail back in the 70s was $299.50 and was offered in semi as well as select-fire.

Nicholas C

Co-Founder of KRISSTALK forums, an owner’s support group and all things KRISS Vector related. Nick found his passion through competitive shooting while living in NY. He participates in USPSA and 3Gun. He loves all things that shoots and flashlights. Really really bright flashlights.

Any questions please email him at nicholas.c@staff.thefirearmblog.com


  • Vhyrus

    I wonder why they went with that design. It wouldn’t have taken much more to throw a recoil pad on the back and make it a true bullpup.

    • Andrew

      Yeah, except spent shells eject from the top, and it has a reciprocating charging handle on top. So if you try to shoulder it, you’re gonna get brass in your eye and take a charging handle to the teeth.

      • Vhyrus

        Unless, of course, you cant it to the side, like it’s designed.

        • echelon

          But then your traditional bullpup design wouldn’t work if the pilot had to operate it left handed or was left handed. This design, though not perfect, is at least an example of someone trying to think outside the box and create something that has a bullpup configuration and could be readily fired from either side without the ejecting brass issue. Although apparently, if it’s a Tavor, it’s not a big deal and we should all just live with it! hahaha.

          • EthanP

            You could have a simple arrangement like the High Standard M-10 shotgun. After all, the recoil is neglgable. You would only need something to lengthen pull. But then you’d have a SBR and have to deal with ATF.

      • Cymond

        When I was young, I couldn’t see why the armpistol was considered a pistol instead of an SBR … until I held one and tried to shoulder it.

  • Geo

    Cover that baby in rails and it’s ready for the American market.

    • Dick is a Dick

      I imagine that especially the ”tacticool” folks would shell out money, yep.

  • Michael

    Chambered in .556!!!

    • Mystick

      Must have a hell of a kick…

      • claymore

        Surprisingly enough it doesn’t. It was very comfortable shooting one.

      • EthanP

        Actually no. It was quite comfortable for recoil. It did need the long flash hider (extra cost) due to excessive muzzle blast and flash. I tried to duplicate .221 loads but it would no longer cycle. With standard 5.56 m-193 ball, it was quite reliable. Useless, but reliable. Modern sight rails would help a lot.

        • Zebra Dun

          Could be it needed a noise suppressor also.

        • Mystick

          Referring to the .556 cal…. not the 5.56mm 🙂

          “Bushmaster took the design and chambered it in .556.”

          • jerseydave

            LOL, nicely observed! 🙂

  • erwos

    My understanding is that Gwinn Firearms changed the caliber to .223 and called it the “Bushmaster ARM Pistol”, not Bushmaster. Bushmaster later bought Gwinn, and in a fitting twist, got their Bushmaster pistol.

    There was also a rifle version, IIRC.

  • badTFG

    “chambered it in .556”


  • William Johnson

    The one that got away, had a chance to buy one in the 80’s for $300 and didn’t.

    • Beaumont

      Yep, one of those guns I should have bought for the cool points alone. I’d be the raddest dude on the range. Usefulness of the gun is not a factor in this equation.

  • claymore

    I actually had one of the .223 ones. Wasn’t bad fun to point and shoot for the fun of it. BUT I wouldn’t take it on any operations. One of the few almost bullpups that I could shoot left handed without brass in my face

    • echelon

      Over on the Tavor story I mentioned this same thing…apparently brass in the face isn’t a big deal, don’t you know? 🙂

      • Zebra Dun

        Down the old Utility shirt was the pits!

  • Ken

    A friend of mine has one and says it’s an unreliable piece of crap.

    • EthanP

      I keep hearing that. I suppose I had a rare one that worked? Mine was a piece of junk. But it always went bang. The only exception was when I tried to duplicate .221 Fireball to reduce the muzzle flash/blast. FYI, those 221 equivalents worked fine in a Mini 14. Left a neat pile of brass 8″ from the breach.

  • HoustonGunBlog

    Thanks for featuring my video. I love these arm pistols. I have had 4 or 5 different examples and they all proved to be reliable and fun to shoot.

  • hkryan

    Looks like a pain to change magazines! Is it?

  • janklow

    ah, one of those 1970s/1980s firearms so RIDICULOUS that MD had to ban it.

    • EthanP

      Only reason I bought it was to spit in the face of the ban croud. I was always dissipointed with it. But unlike Leigh, I found it very reliable even with my handloads. As long as the loads were close to spec. To hkryan; Not really. The gun rests on your forearm for support. If you’re a southpaw it can be difficult to access the mag release. But righties, no problem.

  • Paul Zimmerli

    Fall back and regroup, Nick! The original design by Dale Davis at the Air Force Armaments Lab at Eglin AFB, Florida, was for a .17 caliber weapon. It had three sets of rudimentary front and rear sights, so it could be fired tilted 45 degrees left or right or held upright. I handled the original, and it would have been better than the .38 Special pistol!

  • Leigh Rich

    I shot one way back.i am old. Not a real reliable pistol in its time and very expensive then too.

  • EthanP

    I had one once upon a time. Got rid of it long ago. It was a piece of junk. The top cover moved under recoil. The sights were absolutely useless. A 20 rnd mag rapid fire made it too hot to hold. Had to wear a glove.

  • Zebra Dun

    That sucker would get uncomfortable hot in an full auto sustained action.
    Just the thing a SAC BUFF crew would need after ejecting into another hostile nation after just nuking the place.
    A heater.

    • jerseydave

      It they are in Siberia….

  • Michael

    Is this legally a pistol?

  • Rich

    I used to have one. It was a POS – the rear sight pivots – and doesn’t stay in position. Note that the front sight rotates. It was difficult to hit a piece of typing paper at 50′. I couldn’t hit a man at 100m with it if I had all day to do it.

    To top it off, it jammed … a lot. When the trigger guard fell off, I sold it.

  • torn

    Is that the same as in the NatGeo Gang docu about the crips



  • Schnee

    Here’s mine with a few mods I did to it. Grafted an AR15 front sight to the gas block, welded a peep-hole knob to the charging handle. Radiator hose on the charging handle. Laser on the gas block (best way to aim because you fire it from the hip. Cerakote OD Green and SIG Gray. Oh, and Armalite green pistol grip. Fun fun fun gun to shoot.

  • andygold

    I still have one, I purchased back in ’89. Back then it was totally reliable. Recoil was totally absorbed by the shooting arm. Now, I pull it out of the safe, lube it up, and it functions solely like a single shot. Dropping the bolt always chambers a round with no issues, and it will fire, but it will not go back into battery with the second round. can’t figure it out, and MGI won’t even return phone calls. Anyone have this “single shot” issue?

    • jerseydave

      It may have only been designed to last a short time, as it was an “emergency weapon.” Shooting a few magazines to buy time for an extraction, etc.

  • Secundius

    @ Bushmaster IMP, Individual Multi-Purpose .223-caliber (5.56x45mm Nato).

    The gun was originally meant for downed B-52 Air Force Crews, survival pistol. It was later replaced by the AR-7 Survival Rifle.