MAC-10

[cryptomon]

Hello all. I have recently purchased a MAC-10, in 45 ACP caliber that fires from the open bolt. I am trying to classify exactly what I have and what the markings mean. At the rear of the receiver is a snake logo in the shape of an S with a target center, which I am almost sure is the Cobray Industries logo. The next marking is SAP which I have been told stands for Semi Automatic Pistol and was a marking used for open bolt semi autos that were grandfathered by the ATF before requiring the manufacturer to go to a closed bolt design. The next marking is a three line banner marking that reads; M10 CAL 45 AUTO; RPB INDUSTRIES, INC.; ATLANTA, GA. U.S.A. When I look up RPB industries in the Blue Book it says the guns were manufactured by Masterpiece Arms. There are no M-10 listed under Masterpiece arms. When I look up Cobray industries in the Blue Book it references S.W.D. Incorporated. There are M-11 in 9mm listed under this section. Finally, under the heading of Ingram in the Blue Book, I find a listing that describes my handgun accurately i.e. M-10, 45 ACP, open bolt, discontinued 1982.

My question becomes, what is the correct reference for my pistol? Is it an Ingram? Is it a Cobray? Who manufactured it? RPB, S.W.D., Masterpiece Arms? Why is a Cobray marking on a pistol they never manufactured? Is my gun some kind of hybrid made from parts? It doesn't appear that way as the finish is an exact match and the fit is perfect. I have seen other examples of my pistol for sale on Gunbroker with the exact same markings and described in various combinations of all the versions above.

Any help or information so that I can speak accurately about my pistol would be greatly appreciated.

 

[CapnMac]

Sadly, the "Blue Book" is not all-inclusive.

SAR has a good write up of the industrial history: https://www.smallarmsreview.com/display.article.cfm?idarticles=3191

The parts were made and marked in batches, and passed, from owner to owner as each tried to create saleable product.

The MAC series has more convoluted history than Auto-Ordnance Tommy guns.

You may want to poke around Ian's site, here: https://www.forgottenweapons.com/

Although he probably has more content on the Stemple versions of the RPB MACs.

 

[cryptomon]

Wow. Thank you for the information. No wonder no one can get it right. What a convoluted mess. I know my pistol was manufactured in 1982 right before RPB changed hands but I had no idea they lost their manufacturing FFL to the ATF. I thought they were just required to change the design to closed bolt. I guess I will call my pistol a Mac-10 made by RPB.