When Lehigh Dave first made the adapter it was not as loose... He is a perfectionist, he is not much for loose fitting parts, so it was tighter and snug in the sample gun that he was using. But as testing went on and the different guns indicated the tolerances in the bolts varied over a fairly wide range, so the slot was opened to allow it to fit a greater number of guns.

Just drop the primer in the the adapter.... close the bolt and shoot the gun... oprn the bolt pull it back to extract the spent primer... turn the gun to the side and the spent primer will fall out...

Drop a new primer in and repeat the process... slick as a whistle.

When you install the new primer primer I hav found it is easiest for me to put the gun on a verticle plain set the primer on the ledge of the action and adapter then flatten the gun a bit and the primer falls in place. After you have done this a few times it becomes automatic amd easy... even to the point that you no longer worry about hunting with it.