Question on the 2 3/4"-70MM chambers: When did 2 3/4" 16 and 20ga shells first appear? Anyone with very old catalog information? We know that in the case of the 16ga, American guns weren't factory chambered 2 3/4" until the 20's (even 30's in the case of some companies). Concerning 20's, the Winchester Model 12 started out as a 20ga--chambered 2 1/2". Makes me wonder about pre-WWI European guns, especially smaller bores, with 70MM chambers. Were they shooting 2 3/4" back then? Something doesn't add up here.
As far back as 1886 and as far away as Russia, Sabaneev wrote in his book literally: "Shells come in three sizes: standard - 65 mm, long - 70 mm. and extra long - 75 mm".
I think, early makers were quite pragmatical about chamber length, making them just as long as necesery to fit the desired load. But. I used to load BP according to XIX-century recepies, and it's interesting, but a 70 mm paper shell has just enough room for 36 gramms of big shot with appropriate BP load, sufficient wadding and a roll crimp. So it seems logical that in BP days 70 and 76 mm chambers were more common than after introduction of nitro powders, which take much less space in a shell.
