Mike, not that anybody was eluding you over at the L.C. Smith site, but I don't think that anybody has ever measured or tried doing so, of if they have never posted.
Anyway I took 3 forends all from Featherweights, top one is from a 1927 Field Grade pull off forend. Middle is from a 1919 16 ga. Field Grade with ejectors, bought gun it has a beavertail on it and not the right type, went to Gunparts (Numrich) and bought one. They sell ones for ejector (slot cut already) and non-ejector. Cut too deep where the barrels lay and wouldn't fit right, sloppy on barrels. Had to add a piece on each side,(you can see the slit where I added the piece) and try again. Now waiting for another piece of nicer wood and make another one.
Bottom is from a 12 ga Ideal Grade with the roller release also. You can see from the photos that they are all about the same, and yes I would say that they would fit from a 20 ga -12 ga. Like you stated the only difference is in the width of center rib.
Hope this helps, David
