That’s a lot of shooting and I have one of those. I just oil all of mine though I have no real time to wear out a lock on any of them. I do have a flinter whose lock nicely engraved required a bushing. The rifle was built in1980 according to the engraving on the barrel by the fella who built it. I had to purchase the rebuild kit from Track or Dixie I forget which. I think it came with a tumbler, bushing brass, and a fly. Surprisingly the guy i had install the brass bushing did a great job. It’s a small Siler lock. I don’t remember if it is a L&R or Chambers. All I did was drill the plate. I bought the gun from a older than me guy off gun broker. He supposedly had it built. He didn’t tell me the lock was warn. The barrel is fine for all the shooting it’s seen. You could cock it and it would hold but if you blew on the trigger it would fire! I was able to find the lock at Dixie and used that until I got the lock professionally repaired. I replaced the touch hole; the one that came with the rifle you could drive a small truck through. I don’t know what it is about this rifle but it is close to my favorite. I don’t shoot it as much but it’s a fine shooter and the ignition is perfect.Cleaning and greasing. Otherwise if you shoot it a lot, you might be removing the cock to fit a bushing into the lock plate.