Figure choke from pellet count ?

[Pa SxS]

Rick, attached is a "Charge To Be Used" found in the 1888 catalog. It shows the recommended shot weight and drams for each gauge. Looking at the same time frame in the stock books, normally for a 10ga you see Parker using size 8 shot in a 24" circle at 45 yards. Parker seemed to switch back and forth using either size 7 or 8 shot through the years. That was their default size. Customers sometimes specified to use a certain size shot in the Order Book depending on what the gun was going to be used for.

Hope this helps.