Oh I am sorry my friend....I didn't notice you'd already told us !
<-----blushes and says sorry to the screen.
If the headstamp says RA 41 then it is definitely a 30-06 made in 1941, (Remington Arms Co, Bridgeport, CT, USA).. The reason for the minor differences in size are down to the fact the poor thing has had a good kicking over the past 69 years since it was made. A nice find and, where there's one, there will be more, but you may need a metal detector to find them.