I recently picked up what I initially believed to be a sporterized military mauser (the owner inherited the rifle and knew nothing about it) The rifle came equipped with a scope that I expected to find some markings under, there were none. The only markings on this rifle are below the wood and only states that it is an FN made in Belgium with the date code and a serial number (receiver, barrel and stock all match) No designation for caliber size. I brought it home expecting a big bore mauser caliber but i'm finding its something different. The only bullet I could find that was close to fitting in the muzzle end without sinking to the neck was a .375 H&H but the .375 H&H looks to be too long. The only caliber I can think off hand that is close to this diameter would be a 9.3x62mm which is a pretty hefty dangerous game caliber and not one you see too often. Does anyone have any info on commercial FN Sporters sold around this vintage(1951)? My local smith has about a two week back-log right now for a chamber cast to be certain and i'm curious what the history is on this old rifle. Are there any other standard action rifle calibers that are close to a .375'' diameter that i'm unaware of? Any help is much appreciated! I'll try and get some pictures up as I don't have any at my disposal on this computer. Thank you.