The Western Super-X shell in 20-gauge came out in 1922 in a 2 3/4 inch case, so there was likely some demand for a gun with longer chambers. Of course it seems the vast majority of Nimrods just started shoving those 2 3/4 inch Super-X shells in their dainty 20-gauge doubles chambered for 2 1/2 inch shells and went on their mery way absorbing recoil and eventually cracking the dainty gun's thin wrists!