12 gauge choke tube
 

What choke wil deliver the tightest patern for a 12 gauge

as tight as you can get with the right load . .050+

You'll need to experiment to determine that. Lead, steel, non-tox, shot size, shell size, buckshot, even the shape of the shot -all will pattern differently. Studies years ago revealed that a modified choke patterned better with steel than full. Pick a load you like and then hit the pattern board. This will also tell you if the gun fits you well by having the patterns hit where you're aiming. A tight pattern that shoots low and left isn't much good unless you compensate for it or have the gun fitted to you. Only testing can reveal these things for you.