Your modified choke will kill every turkey it hits as long as you keep your shots within the limits of your gun.

Simply pattern the gun at various yardages and stay within that acceptable yardage when it comes time for the shot. The other thing you want to be sure of is to check your guns point of impact so you don't get any surprises if one comes in up close and personnal.

Yes it is nice to have a gun that will "mow'em down" at fifty yards but it is not a prerequisite to go turkey hunting. Over 90 % of the turkeys I have killed with a shotgun have been under 30 yards and a number of them under twenty. For some of these tight shooting guns if the bird is under twenty yards your handicapping yourself.