i have found the opposite in my shotguns. full chokes in 00 and 1 buck always performed better on groups. im not talking about turkey chokes or extra full. modified always scattered them too much at 50 yards. i guess shot distortion could happen with a extra full choke . i dont know what the standard is for the size of chokes but im gonna guess brands will vary and you will need to try a bunch of things. if the choke says not to use buck shot then i would follow the warning for sure though.