I got one from e-gunparts.com, which is Numrich. They have schematics for many guns.
Date code stamped on left side of barrel, go to Remington Society of America for diagram and chart.
It's an off-branded Stevens Model 311, worth $150-$250, made between 1920 and 1948.
describe the type of shotgun and recheck the serial number
50 Bucks...
Model designation
There is no diagram except the one stamped on the inside of the fuse box cover.
This shotgun is in the neighborhood of 100 years old. There is fairly extensive information online available on this shotgun.
$250-$350
Hopkins & Allen
The number is stamped on the intack
You can find it stamped under the forarm on the under side of the barrel and on the forarm its self
If it is a double, remove barrel and you will see it along with serial #.