By "fail to fire" I assume you mean droping the hammer on a live round with no boom...
Did you look at the primers? Were they dented?
Many auto pistols, even well maintained ones, can get a heavy build up of brass shaving inside the firing pin channel. These will eventually put enough friction on the firing pin to impede it's forward movement.
Striker guns like Glocks and XD's are more prone to suffer from this than hammer guns like the 226 but being a "range gun" certainly makes it a possibility.
I've owned a 226 .40 since 2004. It's trusted as my quick access HD gun because it's the only auto pistol I've ever owned, "and that's a respectable list", that's never malfunctioned on me.