835 Grand Slam, .690 Mossberg Extended factory choke and 3 1/2" #6 Winchester XR.
I also like the same gun with a .706 choke and Federal Mag Shok 3" lead #4's.
The last turkey I killed using the .690 choke and Remington Heavy Shot High Speed #6 in 1 1/4oz. Smoked him at 30 yards.
My 835 isn't picky about which brand of shell to use. It has patterned every shell Ive used and Ive tried almost all brands.
The best money you can spend is to have your barrel honed to a mirror finish and use the right choke for the size shot and type wad your shells have.
And, lastly if you call them in real close it doesn't matter what ammo or choke you use. h.h.