I have one Pete. It is a C. F. Leader hammer gun with laminated barrels. I think it is from Birmingham around 1875. I assumed jug choking was done prior to modern choking but I now see there is a dual function to jug choking allowing a round ball to pass through for larger game while having choke for sporting clays (just kidding).
I have not shot it for years and I am pretty sure it is in the back of the safe so a pain to get to but I think it is marked "not for ball" which now makes no sense to me.
If it is, as you remember, marked "Not for ball" It is strange. Why would they make a gun with a recessed choke and then mark it "not for ball"?
Maybe the gun was originally cylinder bored and then, to give it a little more range, jug-choked later.
Pete
