Does anybody know the throat diameter of Argus SLR bayonet mount? I know its flange focal distance (register) is 44.45mm, but I don't know the diameter of the mount. Specifically, I'm interested to see if it's the same as Minolta SR/MC/MD mount, so that I can use an Argus lens with a small amount of conversion...
Which Argus camera do you mean? They seem to all use different mounting for lenses. Most Arguses are rangefinders, not SLR, and those use a model-specific bayonet mount or in the earliest models a simple M39 screw mount.
The one SLR-type Argus is called just Argus without a model name. Those are not made by Argus themselves but instead Argus rented the model and manufacturing capasity from Mamiya, using their Prismat SLR body as a base, and they did this with a couple of other camera manufacturers as well. Mamiya Prismat has an Exakta mount, but in Argus bodies and lenses they used a unique Argus mount. This mount can not be found in any other camera model. The Exakta mount comes close, and Nikkorex F mount even looks identical but the Argus mount works differently inside. Nikkorex F camera's mount is better known as the Nikon F mount.
There is an adapter for M42 to Argus camera body. In this adapter the M42 screw thread is on the inside of the flange going in the camera body. This means the opening in camera body (throat diameter) must be somewhat over 42 millimeters. The three bayonet lugs extend the mount outside diameter by a few millimeters more. Chances are that the dimensions are a very close match with Nikon F mount (throat diameter 44 mm). Even so I would not try to attach a Nikon lens into Argus body, or the other way around, because the in-mount mechanics are different.