For any of you who are using the older RCBS 'prime on press' primer feeder tubes;
I like this system. Plenty of leverage, faster than a hand squeeze prime tool, and way easier on the wrists and fingers. There is one flaw, however...when priming cases (the tubes don't hold more than 50 primers at a time), everything works great until the last two or three primers. Without the weight of stacked primers on top of them, the last couple primers either fail to load into the cup or tip sideways...not a good thing.
This was easily remedied by purchasing a length of brass rod that will fit in either the small or large primer tube. I placed a slip on rubber cap on one end then cut to length so that the rubber cap rests on the upper end on the tube when the other end or the rod is level with the primer feed cup. The weight of the brass rod keeps a constant feed pressure on the primers, and the rubber cap provides a quick visual cue as to roughly how many primers are left. This has made all the difference in the world for smooth primer feeding without mishap, can't figure out why RCBS never included something like this as standard equipment.
I purchased both the brass rod and rubber cap at Ace Hardware for next to nothing.