As a Winchester model 12 collecter the difference is easy to tell the difference. The model 12 and 97's were able to be disassembled just ahead of the reciever. The entire gun broke down in approxamately even halves. Modern guns just have removeable barrels leaving the magazine tube still attached to the reciever, while the 12's when taken down had the barrel and magazine tube disassemble as a single unit. I have never owned a model 25 and assume they disassemble by simply removing the barrel. Shotguns dont have the same threading process as rifles. Rifles are screwed togeather with much closer thread tolerences and are attached to the reciever via a vise and large action wrench. A shotgun has looser tolerences and is designed to have the barrel removed by hand with a single quarter turn and then extraction. The thread pattern is called an intereupted thread.
