Rare Full Auto M-10 (Aka MAC-10) .45 ACP Carbine

It was 1981, I was a teenager with a huge appetite for all things gun related. At the time, I had owned a Colt AR-15 SP1 for three years and had a nice little collection of military-styled semi-autos which also included an Iver Johnson M1 Carbine Paratrooper, a stainless Ruger Mini-14, and a small pile of other firearms. For Christmas that year, I would get an UZI carbine, but before that I saw something very interesting advertised in Shotgun News - it was an open-bolt M-11 pistol in .380 ACP.

The M-11 pistol is the semi-auto version of the M-11 submachine gun which is the smallest version in the Military Armament Corporation family of pocket garden hoses which also include models in 9mm and .45 ACP. For you younger guys, that’s what we called MAC subguns over 40 years ago because they sprayed bullets at such a high rate of fire – like shooting a garden hose. Now, I want to address something before going further. Many times, these little submachine guns are referred to as MAC-10s and MAC-11s. Although Military Armament Corporation didn’t label their skus as such, the shooting public did, and it stuck. So much so that ATF also has classified these, and any copycat versions, as “MAC-10-type” machine guns. Is this as incorrect as calling an MP-40 a “Schmeisser” (very common especially decades ago) when Hugo Schmeisser had nothing directly to do with the actual design of the MP-40? No, not in my opinion. However, calling an RPB-manufactured M-10 submachine gun a “MAC-10”, when Military Armament Corporation was out of business for many years before it was made, will raise a few eyebrows if stated in front of certain collectors and firearms historians.

A Very Brief History

In the 1960s, Gordan Ingram designed his M-10 submachinegun as a compact, inexpensive submachine gun for the armed forces. He actually wanted to see it issued across all branches as a standard-issued firearm to all troops (what arms inventor hasn’t?), but soon he realized that his best bet would be special operations sales. Although the design is considered successful, by the mid 1970s, after some sales and some mismanagement, the company went on the chopping block and years later another company would be making “MACs” and that was RPB Industries – one of my favorite gun companies of all time. (For more information on the history of this famous gun design, as well as other companies which made it, please search “MAC-10” or “Ingram” on our website. 

Also see Dr. Will Dabbs' article The MAC-10 Submachine Gun: Everything You Need to Know Here

The Open-Bolt Operation

The RPB M-11 pistol I had fired from an open bolt, and 1981 was the last year that open bolt semi-autos could be produced as BATF (as they were known at the time) concluded that open-bolt semi-autos were too easily convertible to full-auto. They were correct as a few minutes with a file will prove it. (The Founders intended us to possess all military type weapons uninfringed as insurance against tyranny- head over to our 2nd Amendment section to continue on that subject.) The open-bolt semi-auto operation was also the first firing mode of the M-10 carbine we will discuss in a bit.

This RPB M-10 submachine gun started off as a carbine and classified as a rifle by BATF. Since it was made before BATF halted open-bolt semis, it has that operation as many blowback pistol-caliber carbines did back in the day. The reasoning from manufacturing standpoint is simplicity in operation which converts to cost savings. The addition of a hammer, modification to the bolt, or a more complex design to incorporate a striker-firing pin system, etc. adds to the price. The disadvantage to these older open-bolt carbines (which are still legal to purchase as they are grandfathered) is that they aren’t near as accurate as closed-bolt designs since the large heavy bolt, with fixed firing pin, strips off a round from the magazine, hurls forward with all that bolt weight (needed in a blowback firearm) and spring force to fire the round. It literally shakes the gun off target.

Some models of open-bolt semi-auto centerfires in the 1960s and 1970s included the Franchi LF-62, a semi-auto carbine version of the LF-57 SMG (later declared a machine gun due because of it firing full auto by manipulating the safety), the Thompson-like Spitfire (also made by a few companies under different names – the Spitfire was also declared a machine gun by BATF), Demro Wasp/Fox carbines, M-10 and M11 carbines, as well as some others. By the very early 1980s, and before the open-bolt ban, only a couple new open-bolt semi-autos were introduced such as the Interdynamic KG-9.  However, not all pistol-caliber carbines in the 1960s and 1970s were open-bolt. In 1968, J&R Engineering introduced the M-68 carbine which morphed into the M-80, and later into the Wilkinson Terry Carbine - all of closed bolt design and extremely accurate even by today’s standards (I own two). Auto-Ordnance introduced closed-bolt versions of their famous “Tommy Gun” with the 1927 series, and IMI announced their closed-bolt UZI carbine around 1980.

RPB M-10 Carbine, Converted to Full Auto

Before Republican President Ronald Reagan banned newly manufactured machine guns for civilian sale on May 19th, 1986, an individual could purchase a machine gun for personal use or convert a semi-auto into one. There were a couple of ways to get a “MAC” machinegun back then. The most common way was to find a “Class 3” dealer (01/class 3 FFL) and order one and these transferred on a BATF Form 4. Prices for M-10 and M-11 machineguns back before the ban were around $350-$400 and I even remember way back when the $200 federal tax stamp cost more than the guns themselves!

The other way was for an individual to own one was to use a BATF Form 1 which allowed an individual to register and manufacture a National Firearms Act-regulated firearm (machine gun, suppressor, AOW, short-barreled shotgun, short-barreled rifle, or destructive device). This is something very common today with short-barreled rifles. Basically, the individual would fill out the Form 1, provide fingerprint cards, and payment of $200 mailed to BATFE. After the form was approved, they could convert their gun legally. In the case of an open-bolt M-10 or M-11, it is just some filing work, unless the owner wanted to make it select-fire which would involve additional machine work and a few additional parts. Many magazines at the time, like FIREPOWER, gave detailed instructions in articles on full-auto conversions, and Shotgun News had all the sources for the parts needed.

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Another way was to take your open-bolt semi to a licensed manufacturer (07/class 2 FFL). They would convert the gun, register it, and file your paperwork for transfer approval. They would also engrave it with the name of their company, city and state. A lot of these NFA-licensed companies were small, and I mean single-car-garage small, and they had limited tools. I’ve been to a few back then and many times all they had were a drill press, engraving pen, letter stamps for marking, a Dremel tool, and some hand tools. Not even a cheap lathe or mill! Their money was made on gun orders and selling at gun shows -the owners were hobbyists as far as any “gunsmithing” work. However, some of these small shops were highly professional and expert machinists and gunsmiths. Converting an open-bolt M-10 only really requires a file (or a rotary tool) and an engraving pen. This model was marked using an engraving pen and as amateurish as the markings may look, it is a statement of the history of that time, a history I have fond memories about. I think it’s sort of cool.

RPB M-10 Carbine Submachine Gun - $9,700 and it’s yours!

As it’s been stated, this firearm started out as a rifle with a 16-inch barrel. It’s an RPB M-10 Carbine in .45 ACP and was converted by M.D. Ordnance of McHenry, Illinois. It has the same lower receiver as any semi-auto open-bolt M-10 pistol in .45 ACP. When M.D Ordnance converted it, I assume they just did the filing method which basically involves modification to the disconnector. So, the gun is full-auto only (or “fun-auto only” as I like to say-I made that up BTW). If the new owner wants it to have the select-fire feature, they, or a gunsmith, will have to drill a hole in the lower receiver/frame for the selector and buy a few additional parts – this probably should not cost more than $300-$400 with labor.

This firearm is a great deal because transferable “MAC-10s” are selling for $11,000-$15,000+ these days. Not only that, this one comes with a pistol/SMG upper, two magazines (modified M3 Grease Gun mags), two rare M-10 retractable stocks in two different lengths of pull, a slotted barrel extension, and a custom fixed stock made from a Choate M1 Carbine E2-style stock. Best of all, that rare carbine upper with adjustable rear sight is something that is not seen often these days – it’s a very valuable item. Altogether, a steal at $9,700. If I didn’t just spend a pile of money, I would have snatched it for myself as soon as I saw the ad on Sturmgewehr.com! I’ve owned many “MACs” in semi-auto and full-auto and still have a couple, but let me tell you, there’s nothing like a full-auto M-10 dumping .45 ACP out at over 1,000 rounds per minute! If you are interested, please contact Guy Adams: guyadams12@gmail.com.

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