So, I came into possession of a sporterized Carl Gustav Stads Chileno Mauser. Can’t find a caliber designation on this thing anywhere. Everything is nice and the action is smooth, but the problem is I am a lefty and it is obviously a right handed bolt. Any opinion on caliber or value for this thing? It appears most on-line listings show caliber as 7x57, but without markings I hate to just start throwing ammo in there to see if it chambers.