Detonics MkI at RIA: The Original Sub-Compact 1911

Today we are accustomed to seeing sub-compact 3.5″ 1911 pistols for sale from a whole bunch of manufacturers – but this was not always the case. Making a really small 1911 actually run reliably is not a trivial proposition, as the slide velocity and spring force become very touchy, and small changes can have major repercussions. The first company to get the kinks out of the mechanism and bring an effective pistol to market was Detonics. Their MkI has a number of interesting features that were quite novel at the time.


  1. Always wondered why the rear sight was so far foreward.

    Was this gun influenced by Curtis LeMay’s cut-down 45 (later used by the Air Force OCI)?

    Had an Officer’s Model Colt in the mid-90’s. It jammed a lot with factory hardball. Ended up trading it off.

    • Jacob:

      The rear sights have to be placed forward because the end of the slid is sloped downwards. I have a feeling this was to facilitate quick thumb cocking if the hammer was held at half cock, though this is of course not the best way to carry a piece such as this, which would be better cocked and locked. A lot of people just didn’t like that idea though, no matter what Jeff Cooper told them.

      I remember that the Detonics was very popular amongst gun writers in the 1980s. I think that Leroy Thompson may have written about one in .38 Super; now that really would be a rare pistol these days.

  2. “small 1911 actually run reliably is not a trivial proposition”
    If so is not designing from scratch better way? If we rework some design it should speed up that process, but if changes done require more and more changes it is really faster? Second question: why Colt 1911 was choice for starting point?

      • There was also the Thomas .45, a DA-only with a rather strange locking system that somehow worked off a backstrap lever similar to a grip safety.

        A friend of mine had one he carried as a backup gun while working as a sheriff’s deputy. The one time he needed it (when six rounds from his .357 didn’t put the quietus to a rather large rabid dog), it fired one shot and jammed, at which point he got to the cruiser, broke out the shotgun, and finished the job with what he’d have started it with if he’d known what he was up against “going in”.

        The next day he took the Thomas to the local stocking dealer and traded it in on a 2″ Ruger Speed-Six .357.



    • The U.S. military had converted full-size 1911’s into compacts: the “general officers model” and the Air Force investigative branch. The rationale was that they had warehouses of 1911’s and armorers who were already paid for. It was estimated that the cost to the government for an Air Force OCI gun was $100.

      Possibly one other reason for the desire for small 1911’s was that a lot of current or ex-military members had trained on it and the operation was familiar to them.

      In the days before cheap CNC and casting technology, there was a cottage industry based on talking large factory guns and cutting them down (as opposed to making new designs from scratch). The ASP (cut down from a full-size S&W) was an example Ian reviewed a while back. A lot of custom gunsmiths turned out cut-down guns. The Pistolsmithing book by George Nonte (1981) had a whole chapter on the subject.

    • Prior to the advent of the current crop of compact pistols, about the only choices for a carry handgun was a 1911(full size or Commander) or a revolver. Revolvers were in the definite majority, with small frame S&Ws and Colts leading the way. I still remember drooling when the Detonics first hit the magazine covers, wondering if we really needed to buy groceries & diapers that month.

    • Tooling up to manufacture a pistol would have been a considerable capital outlay, and that is before the considerable problems of de bugging a new design are taken into account.

      The various long and short slide 1911s have an origin in slides that were bought with tax victim funds, and were cut up and sold as scrap metal.

      Some enterprising gunsmiths bought those cut slides by the 45 gallon barrel full, and began welding them back together, some longer than before and some shorter than before. There’s little point in welding them to standard length.

      The problems of a lighter slide are considerable;
      lighter slides recoil faster, and there’s less room for the springs.

      what the lighter slide and stronger springs mean, is less time for the top round in the mag to move into place and be fed, and less momentum to feed it.

      Those problems would be the same whether an existing pistol is being shortened, or a new short pistol is being developed.

    • The Detonics Pocket Nine was a different design altogether, not based on the 1911. It was double action with a slide mounted safety/decocker and vaguely resembled an oversized Walther PPK. They were not very reliable and were evidently prone to parts breakage. Few were made and although rare, they do not sell for very much on the secondary market, as opposed to the highly sought after 1911 based .45s. I really wanted a Detonics .45 when they first came out, but they were impossible to find in the pre-internet days when you had to get the local shop owner to track one down and order it by phone. I settled for a lovely blued Officer’s Model Colt and was (and still am) quite pleased with it. Detonics also offered full-sized 1911s as well known as the Match Master series. I believe that the original Detonics .45 Associates company was purchased by RoBar sometime back. The company is still in business as Detonics Defense Inc.

  3. and thank you for showing the barrel link with the slide stop in it. i finally understand how the link works. always “knew” it worked differently.

  4. Nice solution to the already over-stressed 1911 spring. The spring shown is called a “nested spring.” The FAL Para uses 2 such action springs. The MAG 58 ejector spring (or extractor spring, can’t remember which) is also a nested spring. I think the Desert Eagle also uses 2 nested recoil springs, the outer springs themselves being stranded-wire springs. How’s that for an elaborate solution?

    • The .357 Eagle I had for years (# 86##, early production) had two parallel springs on a captive assembly that dropped in the front of the frame. It was supposedly a replaceable unit, when the springs went “soft”, but I never had to. Then again, I probably only fired 300 rounds through the bast before I got tired of lugging it around and traded it for a S&W 27-3 6″.



  5. Designing a reliable semi-auto pocket gun for .45 ACP from scratch would take a pretty long time, to say nothing of actually getting it to market without being overtaken…

  6. Weapon of choice scenario:

    Okay, given the “hostage situation” from the Gustloff Volkssturmgewehr article commentary I made, it appears we now have to deal with the same group except they are going for a more discrete approach to getting hostages, having learned their lesson from losing the entire “unit” of terrorists (no, I am not talking about ISIS here, just generic extremist elements). Supposing you, the hero of that situation, were a “marked man,” and that you could just be kidnapped off the street either by sudden vehicular abduction or by getting dragged into a dark alley, which would you have on your person?

    1. Detonics MK 1
    2. Commander’s Nagant revolver
    3. Mauser 1934 pistol with suppressor (or an FN Model 1922)
    4. Nambu Type 94
    5. Stechkin OTs-38
    6. Walther Ultra or PPK
    7. Ithaca Auto & Burglar
    8. M44 SMG with drum magazine
    9. Katana
    10. Drive around in an Adler Kfz. 13 with a friend (and pack a Holek Automat or a ZH-29 while you’re at it)
    11. Or per the usual, screw the budget and add your favorite toys to this list!

    This activity is voluntary. You are not required to participate if you do not wish to do so. Please keep any and all criticism of this post humane and free of foul language.

    Thank you,


    • If there are less than six of them, any DA .357 revolver wins hands-down if you don’t mind making some noise.

      If silence is a priority, screw any gun, even a suppressed one, and get a Bowie knife;

      If they have to lay hands on you, it’s far more effective than any firearm. And cheap enough that you can wipe the prints off it and slide it into a sewer grate without going bankrupt. And unlike a gun, it’s not as likely to come back to say “hello” in the hands of some humorless police inspector.



  7. The Detonics was really big news when it was introduced. It was the smallest .45 of the day.It was also more expensive than the ASP. It like the Semmerling and the ASP the Detonics has a cult like following. They are excellent weapons.Today it is hard to appreciate how hard it was to make a small .45 or 9mm to work reliably. This group of engineers were ahead of their time.

  8. Back in the 1990’s I fired a small frame .45 and didn’t really enjoy it. The slide came back and scrated the web between my thumb and first finger. Plus the recoil was harder to handle than my Springfield Armory 1911.

    • Any compact pistol chambering a powerful round is going to kick. The old Hungarian FEG R-61 PPK clone in 9 x 18 Makarov was known as the “Noisy Cricket” in my circles due to its loud bark and even sharper recoil. The bigger PA-63 PP clone in 9mm Mak was a lot more comfortable to shoot.

      Revolver shooters could always resort to Pachmayr “Decelerator” grips, such as those I used on a Colt Lawman MK III .357 snub I carried as a second gun (during my S&W 645 days), but “Packies” for autos didn’t generally cover the backstrap, which was where you needed it the most.

      The more I see of various ideas for “compact” autos, the more I’m convinced that the best answer is still a compact DA revolver. Preferably a .357, although a .38 Special will work, too, provided you choose your ammunition carefully. The old 158-grain LHP +P “Metro” load is still hard to beat, not to mention Glasers and similar pre-fragmented rounds.

      The great thing about the “specialty” rounds in a revolver is that you never have to worry about whether or not they’re going to “feed”.



      • The FEG 61 in 9mm Makarov is a nice concealment weapon. A short time back some were imported that were rebarreled to .380. I have two that I rebarreled to 9mm Makarov.They are reliable and almost accurate but in no way fun to shoot.At the time it seemed a sensible conversion because of the percieved superiority of the 9X18 round. In the cal .380 the R 61 is also unpleasant to fire.Do you know how the R 61 was regarded by the Hungarian military ? Thanks Andy

    • The compact, high-powered handguns of the late-70s/1980s required a very different shooting style to master.

      I was fortunate in that I learned on a Detonics Combat Master (it was my first handgun), and unlike Ian’s claim, they did suffer from hammer-bite quite badly.

      But they could be quite accurate out to about 50 yards if you had put the time in. They required an ability to hold the pistol quite rigidly right up to pulling the trigger, and then allowing just the right amount of slack in your arm and grip in the follow-through. Doing things like double-tapping was quite challenging past 15 yards, though. But they were really intended for the 5 – 20 yard ranges, and not more.

      This remains my favorite 1911 variant, and losing mine still haunts me to this day (my late-wife stole it during our separation).

    • Hi Denny,

      this is OT

      can I pick your brains on another cut and weld project please?

      do you know if the receiver ring of the magnum Brno ZKK 602 / CZ550, bolt action sporter is the same as the shorter lengths?

      any idea what steel was used in the early 70s? I’m guessing that a 4140 / EN19 (prob with extra silicon and manganese for de oxidizing ) would do for the new mid section extensions and the welding rods/ filler metal (ring and bridge with water running over them).

      is the original likely to have sufficient nickel in it to screw up hot blueing?

  9. I just randomly googled “Para Ordnance Warthog .45 spring,” half expecting to see (given that companies reputation) a single, ridiculously over-stressed coil spring, but apparently it uses a Seecamp spring assembly.

    The Detonics MKIV one-ups the MKI and uses a TRIPPLE-nested coil spring – 3 springs, one inside the other, inside the other!

  10. Thinking about it, I recall seeing a military manual that detailed how to cut down 1911’s into compact guns. Probably for the Air Force OSI. Could be the best source out there if anyone is interested in what was involved. I have no idea what the name of the manual was, just remember running across it in a library in the early ’90’s.

    • Nonte did a three-part series on “chopping” a 191i in Guns & Ammo in 1972.

      And as stated above, he devotes an entire chapter of Pistolsmithing to it.

      “Chopped” .45s seem to have been largely his inspiration, picking up where Armand “Bo” Swenson finished. I simply note that most of them don’t finish up much smaller or lighter than a standard-sized FN P-35 High Power, which is also only slightly larger or bulkier than a Walther PP.

      Some time back, Argentine HPs with short slides were on the market in the US. They were only barely longer than the average “compact” 1911, but retained a full 13-round magazine full of 9 x 19mm.

      I might add that the P-35, in any 9mm iteration, can use any magazine intended for the Beretta M92 or any of its “clones” (Taurus, Llama, etc.) by simply cutting a notch for the FN’s magazine catch in the magazine tube. This in no way prevents the magazine from being used in its “proper” pistol.

      And considering that some extended magazines for the above have 25 or even 30-round capacity, this gives the petite’ P-35 a fearsome firepower potential, exceeded only by that of some of the nastier submachine guns.



      • Thanks for the mag info Eon!

        Back in the 80s I filed new mag catch slots in GP35 mags for several friends who had both GP35s and Marlin 9mm camp carbines.

        The Marlin mag was shorter than the Browning, but the feed lips were identical.

        I didn’t know about the Beretta interchangeability option.

        • FWIW: The 9mm Marlin Camp Carbine used S&W magazines. The flush fit were compatible with the 469/669 family, and thus, with the later 6904/6906. Of course, anything for the 59-series would also work.

  11. Hi All,

    A friend of mine alerted me to this article on Forgotten Weapons. I’d gotten involved in other projects for a couple of weeks and missed checking in nightly. Most excellent site!

    Back in the 1980s I wrote a description of my portion of the development history of the Detonics for I just checked, and it’s still up on their website if any are interested.


    • Your work was indeed ground breaking. I remember my first exposure to your weapon around 1980. There was nothing else like it.At that time, most people who needed a small weapon with stopping power purchased small .357 revolvers. Small is a relative term.
      Weapons such as the Detonics, the ASP or Semmerling were more office dwellers than Field weapons. They screamed American which is fine but in the wrong place it can get you killed. There were plenty of WW 2 handguns floating around for use. One can not be picky in the field.
      At home some weapons were status symbols.
      Your design made the transition to practical weapon.
      The Detonics is perhaps the best concealment handgun of its day.

    • Pat
      Did you ever work with Seecamp cut down 1911s ?
      There was an excellent gunsmith who worked with Seecamp back in the 1980s. He made both the DA and SA only versions from his shop in Paramus NJ.
      His work was first rate.
      Thank You

  12. While living in the Seattle area eons ago, a couple of buddies and I got into IPSC shooting, joining the Overlake Gun Club, in Bellevue. Every once in a while, we’d leave work a couple of hours early and head over to the range to practice for an upcoming match. On one of those occasions a couple of guys showed up in a small pickup, dropped the tailgate and unload several boxes of pistols, and a lot of ammunition which they deposited at the left end of the range (we were on the right). That much shooting gear for just two guys caused a lot of rubber-necking on our part, which immediately escalated straight through the low cloud cover when we recognized the pistols as Detonics. We’d been reading about and hearing about the new gun and had discussed it a lot; we all had a case of the “I wants” without even handling one yet, so we kept gawking at the proceedings when weren’t shooting. Finally, I couldn’t stand it any longer and introduced myself to the guys, and asked about the pistols. IIRC, they said they were function testing the guns, and offered to let us “help” as they were getting tired of shooting so much. We got in quite a bit of shooting on Detonics’ nickle that day. The pistols were (are) surprisingly soft to shoot; I found that when I curled my little finger under the butt, it helped bring the muzzle back on target a bit quicker than when I tried to wrap it around the grip in the regular way. Of course the pistol moved differently in the hand during the firing/reloading cycle than a full size 1911, but the movement was easy to get used too. Each of us remarked on how comfortable they were to fire. I never did spring for one, although one of the guys did, as I really wanted the rear sight to be mounted closer to the eye.

  13. That hammer didn’t stop hammer bite.

    I had a Mk. I Detonics Combat Master, it was my first handgun. And it bit.

  14. Re: the scalloped rear of the slide, “to facilitate cocking on the draw.” I remember years (decades) ago reading an article on the Detonics. It stated that at one time the Detonics was being considered for adoption by a major police department. And the Chief of said (unnamed) department was of the opinion that automatics should be carried in condition two.

    Of course this depends on my recollection of said article being accurate, and of course, said article being accurate in the first place.

  15. I think the main “pop-culture” source for the Detonics was from the late gun writer Jerry Ahern’s “Survivalist” series of post-apocalypse/science fiction novels.

    If memory serves me, Mr Ahern ended up investing in Detonics itself and may have been part of the board of Directors at one point.

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