I don't want an old friend to think I ignored you so I will post what the blue book has on a M1100 even tho I think it is incomplete:The only 12ga 3" listed:Model 1100 magnum Duck Gun-similar to 1100,in 12 (disc. 1987)or 20 3" chamber,recoil pad,VR became standard 1984,Rem Chokes became standard 1987,mfg.1963-88. 100% $400.,98%,$325.,95%,$280.,90%,$260. Subtract $40. if without vr. Subtract $45. if without Rem Choke.I don't have the book handy but other models were chambered in 3" and had the "M" suffix on the serial #. The Special Field runs $510.at 100% and the Classic Field is $675. at 100%.These were great guns but required frequent gas chamber rebuilds as I recall.I also recall the magnums had two gas ports instead of one and required special seals.Someone can correct this if I am wrong but I don't think I am.Please post what they run at the auctions. sam.