I'm working on some turkey loads and have a question for you: In the mid sixties there was a famous gun writer named Mason Williams (not the singer or the ballplayer) who wrote in an article about partridge loads that "lower powder reduces the tendency to blow the pattern" in #9 shot grouse loads. You mentioned that you've done a lot of turkey load testing in the past, and I was wondering if you have ever noticed anything like this? Is this true that heavier powder charges will open up the pattern?Mennoniteman, I agree with what Doc said in the post above.
In other words, I own several 3.5 inch guns, and all of them came with plugs from the factory. It doesn't matter which shell length I try to put into the magazine (2 3/4, 3 or 3.5) - only two shells will go into the magazine when the plug is installed. Of course, you can have another shell in the chamber to bring the total to 3 shells. But only 2 in the magazine with the plug installed.
That's the way it is supposed to work with guns designed for hunting, and it has worked that way with all the turkey hunting guns I have owned.