Peru acquired a large stock of Model 1891 Mausers from Argentina in 1901, and the carbine we are looking at today is a conversion from one of those long rifles - not a factory carbine. A few hundred of these conversions were done in the 1930s for the Peruvian Navy, and the result is a pretty interesting configuration, I think. The guns have 1909-type langevisier “roller-coaster” rear sights, which don’t appear to have been calibrated with the barleycorn front sights of the marked range settings (400-2000m). The hand guard is retained form the 1891 long rifle, and the barrels include a variety of replacement types - this one is Belgian proofed, making it almost certainly an FN barrel purchased in the 1930s as well. The other interesting mark is a date stamp of 1963 on the stock. This seems very unlikely to have been the date of conversion (which is almost certainly in the 30s), and these dates vary between 1963 and 1968 on other observed carbines like this. Whether is was added by an importer for some reason or perhaps as a property mark in the 60s by the Peruvian Navy (or some other reason altogether) remains a mystery.