I definitely would not shoot 2 3/4" shells in a gun that is chambered for 2 1/2" shells. Why would you do it, there are places to buy 2 1/2" out there. FWIW I would shoot low-pressure shells through it up to a 1 oz. shot load.
Thanks- That was my primary concern. I will check the gun before I shoot it and if the chambers are 65 (2 1/2") or not double proofed, I will not shoot it.
I shoot 2 3/4" 1oz loads out of my 2 5/8th chambered Fox SW 12ga (I think that is a common practice). I would be new to the 16ga, and I wasn't sure if folks commonly shot 2 3/4" 1 oz loads out of a 2 1/2" 16ga. From what I gather many of older European 16ga have 2 1/2" chambers (65). After the war more of them were chambered for the 2 3/4" (70). I read somewhere that if the 2 1/2" chambered gun is "double proofed" (do I correctly assume two stamps instead of one?) then the shotgun would be able to handle the increased pressures of the longer shells. Otherwise, it is best to limit shooting to the 2 1/2" shells. I did a bit more homework last night and these shells are out there, but not easy to find and not cheap ($75 to $91.90 per case + shipping):
http://www.polywad-shotgun-shells.com/16gavin7/http://www.ableammo.com/mall/eley_hunting_loads.asp
