Good to Very Good Condition Wide Base Gas Cylinder. These cylinders have a flat spot on the rear ring with either a letter or number code. The same is true of the bayonet lug and in some cases the lug will also have a punch mark. These were produced at Springfield Armory and were observed on rifles in the 1.81M to 2.5M range. They have been refinished with DuLite, which was the original finish and are beautiful. They gauge good to very good with a USGI gauge and are ready for your rifle. Nice cylinder for the collector and shooter alike.