In Parker Bros. doubles a 2 5/8 inch chamber was intended for 2 3/4 inch shells.

Many years ago, I bought a flat of Polywad's Spred-R 12-gauge loads when the assets of the old Potomac River Gun Club were being auctioned off. I shot several patterns with them using my Father's old 2-frame 12-gauge VH choked .035" and .037". The results were very patchy.