longrun said
I have a Model 12 mfg in 1959 with a round post rib, but it is not a donut base. It does not say Simmons on the rib so I am assuming it to be orig Winchester mfg. The proof mark is to the left of the rib and in front of the proof mark on the receiver. Does anyone else have a round post like this one?

Thanks  

The Winchester Model 12 came out with the Winchester Special Ventilated Rib commonly known as the Round Post Ventilated Rib ( without the donut ) in 1956. These posts were brazed to the barrel ( there were two rib variations. The first ribs had squiggly lines running north and south and east and west. The second style had straight striations running north and south only. This information was taken from Dave Riffle’s excellent book Winchester Model 12. It sounds like your Model 12 rib is original Winchester. By the way – what gauge is it.

I do not have a Model 12 with the donut less posts. I have a pigeon grade with the Round Post, Donut Base in 20 gauge modified.

Enjoy your Winchester Model 12

Dick

My 1916 Catalog only lists a raised matted rib.  The 1933 Catalog does list a ventilated rib that was standard on the high end guns and probably could have been special ordered for a standard gun.