Kutter- no offense meant here, but your comment about the Winchester solid milled rib option sent me to my "The Winchester Model 12- One of a Thousand-- by George Madis- Now this ONLY applies to the Model 12's- page 53-- "Winchester's solid ribs were USUALLY made as a part of the barrel, a milling job that required a great deal of time by expert machinists"--
I don't believe that this much detail about the solid ribs was mentioned in the much later published book by Dave Riffle- However, I believe the special order option for a factory installed solid rib ran until about 1957-58.
I now have 9 Model 12's in my working collection- a 1955 field grade 12 gauge 28" mod solid rib-milled on the top or matted if you like. But I also bought a 1933 Model 12 Field grade 20 gauge- solid rib with originally a 30" full choke barrel, but the former owner's son had it out rabbit hunting- and you guessed it- he tripped, got the muzzle in a snowbank- never cleared the bore- and shortened that 30" to about 26.75"- he kept the expanded remained, the solid rib stayed intact while the rest of the barrel had peeled back like a banana- I have that section- and both the remainer of the now cyliner choked barrel plus the "frag grenade section" show the steel of the rib intact to the top of the barrel's radius- If the rib was indeed soldered on, I should think it would have peeled off with the rest of the barrels' circumference.
I mounted that burst shard of 4140 barrel steel on a display board, over the "steel tomb" gun safe down in my "Man Cave" next to the 1979 era Sturm Ruger ad with the great poem "If a sportsman true you'd be"--
