oddball barrels with MAC threads

[MitchWerbellsGhost87]

just scored a lot of random barrels that have MAC threads. I see 4 actual MAC barrels and then 3 unidentifiable barrels (far left and 2 on the right). I have all the old RPB/SWD/Cobray catalogs, they sold various barrels with MAC threads for different gun, but none of them feature this odd variety of barrel. Anyone have a guess as to what those barrels are for? They almost look like they could be revolver barrels?

 

[strobro32]

The one on the left and 2 on the right are not mac barrels. Not sure what they are for.

 

[MitchWerbellsGhost87]

The one on the left and 2 on the right are not mac barrels. Not sure what they are for.

Obviously not mac barrels. That’s why I’m asking… someone has gotta know. They look like they could be for a marlin camp carbine or something the way they thread in with those fine threads

 

[slimshady]

Caliber? Are they chambered? Thread size? One looks like it has a plain unthreaded front end, unfinished or made that way? May help narrow it down.

 

[MitchWerbellsGhost87]

Caliber? Are they chambered? Thread size? One looks like it has a plain unthreaded front end, unfinished or made that way? May help narrow it down.

Don’t have em yet, thread pitch looks to be 3/4x10 so possibly 9mm, one of them is indeed unthreaded. I’ll provide more info when I have them in hand.

 

[MitchWerbellsGhost87]

Got the barrels… they’re 9mm 3/4x10, I’m wondering if they are maybe for these weird oddball side feeding AR15 uppers from a few decades back. They don’t have the wrench flats but those uppers look like the barrels thread in just like these and the length is right.

 

[MitchWerbellsGhost87]

I am now 90% sure they are for the ARC weapons system in 9mm

 

[theduke]

What about the smaller one?

I know they did Beretta 21a bbls , Maybe tec 22 , and something for some Ruger iirc

 

[MitchWerbellsGhost87]

Update!!

I just accidentally stumbled across an ARC weapons system catalog on eBay and purchased it. It has the barrels in it!! I was right! And the smooth non threaded barrel was a 380 conversion. Of course I already sold the barrels… 380 barrel was probably rare ¯\_(ツ)_/¯ damn