No matter what the hardness of each of the frizzen toe, and the spring, you need lubrication at the contact point. After I clean my lock, I apply a little molybdenum grease on a toothpick. This stuff is very difficult to get off and it makes a big difference in the wear factor. I also apply a little to the tumbler where the mainspring bears. A squirt of WD 40 will not wash it away...good stuff.
A little anecdote...a friend who has a really nice longrifle was having trouble right at the beginning of our trail one day, with his frizzen refusing to pop open. I checked the lock, and there was no lubrication between the toe and the spring. I removed my own lock, and with the point of a knife, removed a little grease from my tumbler, and placed it on his lock. Le voila!! Instant success.