Remington stamps an assembly code on the left side of the barrel just ahead of the receiver.
The first letter will be one of the following 12, running from B=January thru X=December, followed by a letter that will identify the year. Shotgun barrels are a less reliable source of assembly date than on rifles, as they can easily be changed, but most aren't.
B-L-A-C-K-P-O-W-D-E-R-X
