With the 'extra' primer in mind, know that years ago, John Buhmiller experimented with placing a standard primer, cup-down on top of the load, beneath the bullet's base. Thus, the bullet's base in a 100% loading, held the primer at that location. The reason for this experimentation and use was to bolster or improve the burning or inconsistant burning of power found in most straight cased loads with today's stick or ball powders.

My own experimentation with John's methods (you are on your own) was when loading in my .458 2" American using H335 powder. I found a reduction in powder of 8gr., along with the primer on top of the powder, produced the same ballistics as before, but resulted in a cleaner bore, less fouling after the shot. Accuracy with this M98 VZ actioned rifle was always cloverleafs, so I could not tell of any difference regarding accuracy.

The intersting findings was that with 60.0gr. H335, I achieved the same balistics as normally found from a heavily compressed load of 68.0gr. when using the 400gr. Barnes bullets - ie: 2,200fps.

As this load was also used with the 500gr. Hornady bullets for 2,059fps, it was not what I would call maximum with the 400's. The same load produced 2,290fps with 350's.