You can also get an inside caliper and measure the inside of the barrel. Bore should be .275 in. This is a Mexican Mauser - most of which were 7x57mm.
Try old gun magazines.
Impossible to answer without a detailed description of the weapon.
Made from 1931 to 1936
Around 1931
1931
That sn dates to 1912 or 1931 depending on caliber.
According to The Gun Traders Guide, this gun was produced between 1931-1935.
38 special unless it's a 38 S&W, then 38 S&W cartridge. should say on barrel.
Made from 1896-1931. The sn you list was made in 1905. @ 426,000 made in total. Depends on condition, caliber and configuration. 500- 2000 USD range.
I only have the serial list to 1931 and it's after that. It will however have a date code stamped on the barrel see related links for a page with details.
Rango - 1931 was released on: Germany: 1931 USA: 7 March 1931 Finland: 12 April 1931 Portugal: 22 June 1931 Spain: 29 October 1931 (Madrid)
Stepping Out - 1931 was released on: USA: 11 April 1931