Mystery Mauser?

[Patrick Chadwick]

The stock disc is '3006', which I believe is a rack number and not a caliber designation.

Agreed, any caliber designation would be on the barrelled system itself, nowhere else, so that it cannot be separated from the barrelled system.

Muzzle is very short, darn near flush with the front sight base from what I can see.

The only reason to cut off the last 1/2" or so off a barrel, would have been that the muzzle was KO - damaged or widened. If, for instance, the cause was a plugged muzzle, then the distortion will have spread further back than one can tell with the naked eye.

For that reason alone, I would never buy such a rifle. Ruined as a collection piece and probably also as a shooter.