What follows is a draft of a future article on the subject. The story is much more involved and lengthy, but space restraints require limiting myself to a more condensed summary.
Comments/critique welcomed - hope you find it of interest.
John
--------------------------------------------------------------
These visually intimidating firearms were once almost as iconic as Thompson submachine guns, but today they are long out of general circulation and almost forgotten. Still, they represent an important chapter in the history of compact rapid-fire weaponry. The story of how they came to be and how they faded from the scene is an interesting one.
Gordon B. Ingram, then with Police Ordnance Corporation, had developed a .45 ACP subgun in the 1960s, the Ingram Model 6. It resembled the Thompson SMG, but was much cheaper to manufacture. In 1964 he left POC and started to develop a compact new design on his own. Prototypes were made in 1965, and the U.S. Army purchased at least one for evaluation in 1966. About that time, Mitch WerBell III had developed some effective firearms sound suppressors at his own firm, Sionics (Studies in the Operational Negation of Insurgents and Counter-Subversion). WerBell was a well-known, eccentric and flamboyantly mustachioed soldier of fortune who was a former OSS and CIA operative. In 1969, Ingram joined Sionics in Powder Springs, Georgia as chief engineer. The company name was changed to the more appropriate Military Armament Corporation (MAC) and it began to make and sell Ingram’s new subgun and WerBell’s suppressor. In 1970 a group of investors. the Quantum Corporation, took over the financially-strapped company. WerBell remained president, and Ingram the chief engineer. However, following a company move to Marietta, Georgia, the new owners quickly forced both men out of the company.
What Ingram had developed for MAC was a submachine gun a bit larger than a normal pistol that would be fairly concealable, simple, cheap to manufacture, reliable, and easy to adapt to suppressors. These guns and suppressors were marketed as a package to the military, law enforcement, and qualified individuals. This first submachine gun, chambered for .45 ACP, was officially designated as the Model 10, but it has since been commonly referred to as the “MAC-10.” Before their abrupt ouster from MAC, Ingram and WerBell unsuccessfully sought to have it adopted by the U.S. military for general use in the ongoing Vietnam War.
The M10’s upper and lower frames were formed sheet steel stampings, which could be economical to produce in almost any serious metal shop. It had a distinctive rectangular form. Inside the upper frame a heavy steel blow-back bolt reciprocated. This bolt’s forward section telescoped over the rear of the 5 ¾” barrel. The weapon fired from an open bolt with a fixed firing pin, and was very reliable in operation. The subgun illustrated is a legally-registered Powder Springs example made in 1973.
Surplus M3 “Grease Gun” submachine gun 30-round magazines were slightly modified to fit, and were inserted through the centrally located grip frame. Shortened 10-round magazines were also available for concealment. A rotary selector switch on the left side of the lower frame in front of the trigger allowed either semiautomatic or full-automatic fire, and a sliding safety was located just forward of the trigger on the right side. The cocking knob was on top, and could be accessed by either hand. It had a slot through which the gun could be aimed. Twisting it 90 degrees in the rearmost position locked it in place, making the weapon “drop safe.” The front and rear sights were fixed. A large ejection port was on the right side of the upper frame. A removable fully-collapsible wire stock was provided.
The barrel in front of the frame was threaded to accept a Sionics suppressor. The suppressor utilized a rear expansion chamber loaded with metal shoelace eyelets and a number of polymer “wipes” in the front section’s spiral interior. These were like miniature doughnuts, with central holes smaller than bullet diameter. The wipes expanded as the bullet passed through, and then contracted to partially seal the propelling gases. The downside of the wipes was that they tended to deteriorate with use, and had to be replaced frequently. A Nomex exterior heat shield was available to prevent burns to the shooter’s hand.
The .45 M10 subgun was used in limited quantities by a number of Special Forces, including Navy SEALs, in Vietnam. M10s in 9mm and M11s in 380 ACP were also manufactured at MAC. Some sales were made to Chile and Argentina, and then to some Asian and South American countries. However the company continued to be underfunded, and was in no position to provide arms in quantity. Restrictions were also placed by the U.S. government on the export of suppressors, limiting MAC’s overseas markets severely. In spite of wonderful publicity when John Wayne, starring as a policeman in the movie “McQ” used an M11, MAC finally stopped production in 1973. It went belly up in 1976 primarily due to lack of military contracts, and its assets were sold in 1977.
RPB Industries, of Atlanta, Georgia then took over production of the M10 and M11 subguns, and also made M10 and M11 open-bolt semiautomatic pistols as well as carbines with the approval of the Bureau of Alcohol, Tobacco and Firearms. This agency later made a judgment that these open-bolt semiautos were too easy to convert to full-automatic. A court order exempted all open-bolt pistols and carbines made or assembled before June 21, 1982 as being legal, but future similarly-made pistols would be BATF-declared as machine guns, subject to registration and a $200 tax. RPB closed shop in 1982 following the BATF reclassification.
Another MAC was formed in Stephensville, Texas, by James Leatherwood. The re-designed subguns made there had a poor quality reputation. In 1983, Wayne Daniels, a former principal at RPB, started his own company as SWD Incorporated. This company began to produce open-bolt subguns with some frames purchased from the newly-formed “Texas MAC” and also used many frames and parts from RPB. A series of “Cobray” closed-bolt semiauto pistols were made. Zytel polymer magazines proved unreliable. Following numerous disagreements with the BATF and a lawsuit over suppressor parts sales, a defiant SWD folded up shop.
Jersey Arms was another manufacturer, and produced subguns based on the same general designs as used by RPB. The manufacturing was actually carried out by Hatton Industries, located in Indian Mills, New Jersey.
Suppressors using wipes were made obsolete when the BATF declared the replaceable wipes and other components themselves as individual suppressors, with each subject to registration and a $200 tax. Understandably, this made the Sionics-type “cans” not very desirable. Straight one-piece wipeless suppressors were then developed and substituted.
Gordon Ingram passed away from natural causes in 2004 at the age of 79. Suffering from cancer, Mitch WerBell died of mysterious circumstances involving his possible poisoning in 1983, aged 65.
Closed-bolt semiautomatic MAC-style pistols are still being made by various manufacturers, but the old subguns and open-bolt pistols and carbines can no longer be manufactured. Collectors prize the legal open-bolt semiauto guns, and their prices have escalated substantially. The M10 and its cousins were bold departures from previous designs, but were of limited utility. Today, they are very interesting collectibles that represent a now-classic and significant design concept.
(c) 2013 JLM
The MAC-10 subguns & pistols - a brief history...
Linear Mode
