I recall reading in some of Nash Buckingham's writings his Father having a Greener 12ga hammer gun with 3" chambers. While the gun itself was British he was getting his shells from an American maker. I will have to look this up but they were the favorite load of a noted shooter of the day. As I recall they were only loaded with an ounce of shot. Nash admitted to "Borrowing" a good many of these shells & using them in his gun which did not have 3" chambers. This as I recall was all prior to 1900.
Info I have read on the 1894 Winchester is that it was introduced with a Nickel Steel Barrel along with the .30WCF (.30-30) cartridge in 1895. The .30WCF was introduced as a Smokeless cartridge & never carried 30 grains of black as is so often mis-stated. Most seem to think that Marlin was likely to be the first to call it the .30-30 simply because they did not want to mark that "WCF" (Winchester Central Fire) on one of their rifles.
