Nighthawk, sorry I did not see it was a 20 ga. I have a 301 in 20 ga and it is 572 constriction stock choke that comes with the gun. I load TSS #9 and 1 5/8 oz and it will put 306 pellets in the 10" circle and 176 in the 20"....very even pattern and at 20 yards I got a good 15" circle to hit him.....shoot a Brrris III red dot with a Sumtoy mount. Have a Remington 870 Fieldmaster that will put 299 in the 10" circle with the same handloads. Mine has to been real clean to do this. I use DA alcohol on a cotton ball after cleaning and before shooting again...to get all the oils out and perfectly clean, dry barrel. It will not do this if the barrel is not clean. I believe that stock choke will give you what you want if gun is cleaned as described. Let us know how it goes.