The 4100, the 1600 and model 7 cdl (6.5 lbs) would be pretty much similar as lightest among ones you mention. They should all have 20 inch barrels.Earlier model sevens came with 18.5 inch barrels. The 1640 normally has a 22 inch barrel. The 1600 is similar to the 4100 . The 4100 has forearm checkering, while the 1600 usually does not. The Remington will have a better trigger. The 4100 rifles look great....have had a few, but could not get the triggers right for me, so ended up selling them.
That's almost right... But the 1640 have 23.622" (600mm) barrel, but only the "Husky" or "H-5000" have a 22" (560mm) barrel.
The 1600/4000/4100/450 have, indeed à 20.47" (520mm) barrel of lighter profile than the 1640.




























