One other thing that comes to mind- A few years ago, Frank Hoppe, trap shooter/instructor, who writes for Trap and Field Magazine, wrote an article. He pointed out how trap shooters who go from singles shooting (from the 16 yard line) move back to their handicap position and feel the need for more "power" in their loads. Many shooters go from their normal loads of 1150 or 1250 fps and start shooting the 1350+ fps loads because they feel the need for faster loads when moving back to their handicap positions. But, when you think about it, when you move from the 16 yard line back to the (let's say) 23 yard line, you are only adding 21 feet to your yardage. When the load is traveling at 1250 fps- and your target is now approximately 53 yards away instead of the original (approximate) 30 yard distance what is the distance in time between the two loads and yardage? A few milliseconds maybe? When you have a shot pattern the size of the hood of a car, do you even have to make lead adjustments when you move from singles to handicap? I never do. Of course I'm no expert. But people like Frank Hoppe don't either. That theory came to mind when I read the articles by Tom Armbrust. No offense, of course. But, that's one of the reasons I never gave too much thought to a primer change unless I change to one that I am not familiar with. Although, don't get me wrong, there is no substitute for safety. So, be safe.