MANY THANKS TO BRUCE DAY AND THE PGCA FOR THESE IMAGES.
The 20g hulls were shot in 2 1/2" chamber c. 1900 Parkers

Winchester AA 12g



Winchester Dove & Quail 12g



Remington STS 12g



Winchester AA 20g



Remington 20g



Remington Game Load 20g



Remington STS 20g



Federal Game Load 16g



Remington Game Load 16g



I have measured the B&P Competition One 7/8 oz. 12g shell and it does measure exactly 2 3/4" opened.