Fred,
Thank you very much for posting your rifle. IMHO it is a model 93 or 95, this is model have the back of M91 and the front of M98. Some time ago I saw a military 93 in 7,65x54mm (Arg.).
Indeed there were two .303 Fraser, one rimless (7,65 Arg.) and one rimmed (.303 British.). IMHO a .303 Brit. Mauser is very unusual. You should have to measure the bolt head, the rim of the 7.65 is .470. This is the easiest way to know.
I have read about the .303 Fraser but I could never get pictures of a rifle. I’m a fan of the 7,65x54 Arg.. It was the first “modern” cartridge designed Mauser as the 8x57 was designed by a Commission (as 88 surely know) .
I highly recommend Hornady ammo for the 7,65

Any one read Spanish? I wrote an article about the 7,65x54mm for a gun magazine. That I can post.

Martin