Ky-Flinter does bring up a good point. It could actually be a 38 caliber. Land-to-land measurement is more important, since rifling depth varies between manufacturers. Unless you are dealing with an original barrel, which could be anything depending on date of manufacture. In the old days, there was no real set standard for bore diameter, as most rifles came with a bullet mold for that specific rifle, made for that rifle. Another thing we don't know is how worn the barrel is. Like Ron mentioned too, we don't know if the barrel has been coned or not, however, I am doubting it, since there were definite lands and grooves reported to you. But some who cone barrels did file fake grooves in, for some strange reason.
It is really difficult to talk about a barrel without lots of info about it. Before I began building rifles, I used to hunt all of my own meat, and I was loaned an old '60s or '70s era CVA 45 caliber rifle because I didn't have one of my own. The guy who loaned it to me said his father had told him it was a tack-driver. I knew his father before he died, and he had told me the same, and they were both right. However, when ramming the ball down the bore, you could tell once the ball neared the powder, that the barrel was pretty much worn out. It took very little pressure to press that ball down that last 3 inches. It eventually got to the point that I returned it to the guy, telling him it was getting to dangerous to fire.
This should not necessarily discourage you from purchasing the rifle, but keep in mind it may need a new barrel, which will probably cost a bit if you want a quality barrel. And re-barrelling is an option, but should not be done if this is an original. Let us know more.
Matt
