I've had similar troubles recently with primers. Never had the problem before, shooting them in my Uberti SAA or my Lever gun, but with my 1872 Open Top, I sometimes get a dent and no boom. If I cycle through and try again, I have a near 100% success rate.
I had been thinking that this is due to the gun, not the reloads. The hammer on the Open Top does not fall particularly hard. Also, the gun is not tolerant of primers that stand proud, so I have made an effort to fully seat all my primers. I don't wonder if I have seated some too deep for this gun.
I don't usually handle the primers, although they do sit in my garage through the Las Vegas hot summer.