Remington 1100 serial number dating
And no matter what Remington says, they did start numbering them in the Measures 26 inches and it is a factory barrel stamped modified and mikes at modified with vented rib.
I spent 30 years making paper out of trees, and the wood is always looking to get even.
NOTE – Some of these year letters repeat, as can be seen below.
After that one brings into play what is known of the history, such as the year first acquired.