Help with mystery Mauser?

[Patrick Chadwick]

From the backsight I guess that it is a sporterized Chilean Mauser. Looks like a stepped (i.e. military) barrel that has been cut back at the muzzle. Why? Badly worn, maybe. In which case - how far back is it bell-mouthed?

I am also concerned about what appears to be a non-original gas port on the side of the receiver. Military Mausers did not normally have this feature. So before shooting this rifle it should be carefully checked out for other "improvements" that the sporterizer may have made. I know that in the US such things as individual proofing are considered unnecessary, or even undesirable, but here in Mauserland such an alteration would invalidate the proof, for the very good reason that it is a weakening of the chamber walls in the region of maximum stress - right there where the left-hand bolt lug bears.

Yeah, yeah, I know someone is going to write in to say that my fears are groundless. But once someone starts altering pressure-bearing components, great caution is advisable. Ten times cautious is better than one time dead.