Two of my barrels don't have any letters on them, Don. And if the letters go clear to Z, would there have been 26 people who assembled barrels over the years? If they skipped two or three letters for some reason, (Maybe because a C looked like a G or something like that) or some years they didn't make any barrels, that would put 1942 on a P. The same with one of mine-#19754 has a S. If they skipped two letters it comes out to 1947. That is when it was made. I do have one that should be pretty new (I don't have the paperwork) #22980 that has an A. Could they have made barrels ahead and put them in storage like they did the frames? Another gun I have #93 has the number 123 (no letter)on it so could gun #93 have the 123rd set of barrels made by someone? We'll figure it out. I sent an e-mail to Ed Ulrich. We'll see if I hear from him.