Chokes what to do

[Double Lab]

That's correct. The difference between the bore diameter and the diameter at the muzzle is your choke constriction. Your best bet if this thing is going to drive you crazy is to send the barrels to a good barrel man and have him evaluate it. Then he would be able to tell you how you can get the most constriction from what you have. Good luck.

[Austin W Hogan]

Boxbirder; With respect to your choke constriction , see several of my PP and DGJ articles about the Super Fox and several Parker competition guns. Choke tapers, measured with a Stan Baker and a jig are shown.
Parker chokes were reamed and polished "to deliver" on the customer's request. Some look pretty bad but deliver tight patterns. It is not necessarily the actual diameter, but the rates of changes in diameter that make patterns.
I would not re cut that choke before counting at least 10 patterns on two days.

Best, Austin

[Austin W Hogan]

Boxbirder; To put a little more on the last note; the aerodynamics of spheres make the trajectory of any single pellet purely random. This allows the use of pure math statistics to estimate pattern variations. The random variation within a pattern is plus or minus the square root of the number of shot in the pattern.
There are 350 shot in an ounce of 7 1/2 shot. An 80% pattern of 1 to 1 1/4 ounce of 7 1/2 shot varies by about =/- 20 shot. A single pattern from a gun that averages a 75% pattern has an equal chance of being 70% or 80%. Don's experience and advice is very good.
Don't fret over choke dimensions; convince yourself you have a good gun by shooting patterns and picking the proper ammo match.

Best, Austin