Hello, my friend has a Remington O3 A3, and want to know what cal. it is. Its an old milatary gun that has been "sportarized". It does not say what caliber it is. Did they make more than one caliber in the O3A3? I have saw the O3A3 in 30-06, but just curious if it was made in any other cal. Serial number is 3776671. any information on this gun would be greatly appreciated. Thanks

All 03-A3's to my knowledge were 30-06. It's possible that a 'sporterized' version might have been rechambered or rebarreled. The military versions never had the caliber marked on them. I would guess that most rebarreled rifles would have the caliber marked on it.

If in doubt take it to a compentent gunsmith and have him check it out, (rather than guess). NOTE: many of the clerks at big box sporting goods stores are not competent.