1913 3" 20g Stevens repeater introduced
http://www.la84foundation.org/SportsLibrary/SportingLife/1913/VOL_62_NO_12/SL6212020.PDF I have one of the Stevens Model 200 shotguns.
Mines a 26" bbl'd version. Slick little gun, but it won't see any 3" shells from me.
Still had the TD spanner wrench in the mag tube. Probably because no body knew it was there. The knurled TD ring shows a few helper marks but not bad.
One third turn rotation of the TD ring and the barrel & forearm assembly pulls forward off the receiver.