I have an RCBS universal hand priming tool. The one with the square tray. It works great for priming large primers and magnum primers. It is a nightmare however for priming small primers. I know how to switch them out and have even had replacement parts sent to me but it is still impossible to prime small primers with this thing. Out of 100 I will have 20 or so that dont seat correctly or have a crease in the primer. I have these issues when trying to prime 5.56 and .300 blackout brass. I ream the snot out of the primer pockets and still have issues. I am using federal gold metal match small primers #205M. Its like the automatic shell holders dont hold the small shells perfectly centered to insert the primer. It a guessing match. The primers wont go all the way in the pocket or it crushes them partially. If you press to hard the shell just flies off the tool with the primer not seated correctly and you cant try and reseat it. You have just wasted a primer. A friend of mine uses the regular RCBS hand primer that uses exact shell holders and he has no issues with small primers. I have thought of purchasing one of those and one shell holder for about $45.00 total and just leaving it set up for small primers and use the universal just for Large and Magnum primers. Then I saw a Frankford Arsenal Platinum Series Perfect Seat Hand Priming Tool that comes with all the shell holders in a kit for $59.00 but I dont know anyone who uses one. I was just thinking that having a tool that uses a shell holder would help my small cartridge alignment and seat my small primers. I dont want to buy all new shell holders though, but I could buy one for just 5.56 and .300 blackout. What is everyone else using????? Any thoughts??