I think there is a certain luck of the draw factor involved in Smith 3rd Gen guns. I have two 39XXs that have very high round counts (30K + , mostly white box of some flavor). Both have some preening of the frame rails, but the cam surfaces are still OK. The barrels on both of those guns have noticeable throat erosion, but it doesn't seem to have much effect on accuracy.

However, I have seen frame failures in the aluminum frames at around 15K. The most common failures were cracked frame rails, cracked dust covers, and preened cam surfaces. Oddly, I have never seen a Smith slide fail. I've had or seen slide cracks in 1911s, Beretta 92/96, and Sigs.

I don't have enough experience with the steel frame guns to even guess.

FWIW

Charles