I'm like Fastcat. In the pre-HTL days my standard loading strategy was 3" Federal Heavyweight 2 oz. # 6s in the chamber then Federal Heavyweight 2 oz. # 2s in the magazine. If the load of 6s didn't anchor the bird the #2s would definitely do the trick. The second shot is never pretty. Your bird is in high gear leaving the country and your probable target is going to be his butt. You need something to break him down in the body. The 2s were definitely bone breakers.
Unfortunately, a few years ago, somebody shot Jack Murray, our TN TWRA Turkey Biologist in the head with a load of 2s while he was turkey hunting. He survived but just barely. The powers-that-be decided that since the 2s would penetrate a human skull, they should be outlawed for turkeys and almost everything else. Once again the weapon got blamed for the actions of a stupid human so they baned the 2s. Now the largest shot you can use hunting small game in TN is a #4.
Luckily, with the advent of HTL, we can still get the effectiveness of the large #2 shot by using the denser, heavier Hevi-Shot 4s and stay legal. At the same time we can fill in some of the holes in the pattern of the large shot by shooting the blended shot loads. Best of both worlds.
I do still miss the Heavyweight 2s though. I once had to finish off a bird that wouldn't stay down on the first shot. He was running down a logging road directly away from me. When the #2s caught up with him, he rolled like a ball. I paced it off to where he dropped. It was 93 steps. One #2 pellet hit him in the back of the skull. Yeah, it was a Hail Mary, but it saved me from losing a wounded turkey.