I'm no expert, but I would say yes, yes, and yes to your questions. If the caliber is 8mm it could be
.318 or .323 bullets and would need to be checked before firing. The military standard changed in 1905
when the 150 grn spitzer in .323" became the standard sized projectile; sporting rifles however did not follow[size=78%] [/size]
suit right away and other calibers like 7x57 or 7.65x53 remained the same as before. Hope that helps.