At my last Cowboy Shoot my 38-40 black powder loads failed to fire in my Uberti 1866 at a rate of almost 50%. I was very puzzled as this has never happened. Inspecting the offending cartridges later showed light firing pin strikes, but that all primers (Winchester large pistol)were seated below the case rim. Rifle inspection showed nothing amiss so I broke down the remaining cartridges. I then used a RCBS hand priming tool and was able to further seat each primer. Those now empty cartridges fired normally in the same rifle. I load on a Dillon 550B which is now 40 years old, but I inspect each and every cartridge I reload for primer seating depth and know for certain none of those 38-40s had high primers. So I guess I will probably now use the hand priming tool as you can feel the primer bottom out in the pocket much better.
