375BSA,
The turks were one of the most prolific buryers of Mauser action rifles, next to Argentina.
The started with the 1871 a bp 9.3 cartridge designed for the turkish rifles. The used the 1884/71, 1888 commission rifles, 1889 / 1891 actions rifles, 1893, 1898, 1905, then the FN 1922's, 1924s, etc.
Most of these, up to the FN 1922 were originally chambered in 7.65x53 Mauser. In the 1930,s they "standardized" most of the rifles in an stock designs and then rebarreled or rebored these to 8x57IS. The actions are an intermediate length. the 1905 is special design with the reciever ring longer than any other and the bolt striker desing with an extra long striker for more sure firing of the cartridge. The stipper stip slot has a milled in high sided slot that is distinctive and the bolt relast also has a hand that wraps around to put pressure on the stripper clip to hold it in place while loading.
The bolt will need to be chosen carefully to match the type of action. A Turkish mauser is not a consistant animal. I have a few different models form when they first came into the country. All the ones I have are very nice rifles. Great wood, bores and shoot very well. The nicest is the FN 1922 and most interesting is the 1905. Can't help you on the odd .375 bore. Good luck.