I have checked "THE BIBLE" of mauser books by Ludwig Olsen and he say Oviedo mausers were built in Spain and that it could be either 7.65x53 Argentine mauser or 8MM mauser caliber however he is also talking about the model 27
Sounds to me like you need to read a different Bible.
Model 1916 rifles were not chambered in 8X57mm or 7.65X53mm. 7.65X53mm (often called 7.65 Argentine or Belgian) was the standard service cartridge of Argentina, Colombia, and Bolivia. Argentina received its weapons from Germany (Loewe, DWM, Mauser), Colombia received most of its weapons from Belgium (FN), and Bolivia received many of its weapons from Austria (Steyr).
All Model 1916 short rifles manufactured at Oviedo armory (including yours manufactured in 1923) were Mauser 1893 pattern rifles originally chambered in 7X57mm, the service cartridge used by Spain from 1893 until 1943, when they adopted the M98-based Model 1943 chambered for 8X57mm, which were made at La Coruna armory. The Guardia Civil (paramilitary police) received the rifles chambered in 7X57mm (Model 1904 standard rifles and Model 1916 short rifles) as well as submachineguns and pistols chambered in 9mm Largo (the military switched to 9X19mm). The Spanish military and Guardia Civil were kept separate in munitions, armories, supplies, etc, until the 1960s due to concerns about another revolution. Spain did not export weapons to other countries, its license with Mauser was very restrictive.
Parts for 1893 Mausers are becoming increasingly scarce. Some parts from 1895 Mausers will fit, but not all.
Your 1924/30 is a M98 pattern rifle, most likely made by FN. Standard M98 and K98 parts will fit it. If unsure of the chambering, have a chamber cast made.
