holl said:does anyone use the ampco bronze nipples
I use the Treso (ampco bronze), as well as Stainless Steel and if they suit my needs the factory nipples as well. I personally have never "Worn Out" a factory nipple, but that's not to say it couldn't happen with enough rounds through the gun.
The main reason to change nipples is if you having issues with the factory ones. Issues that might include not being able to find the correct size cap to fit without messing with pinching etc. Another issue might be that the flash hole in the factory nipple has eroded, was drilled or was just too big in the first place causing nipples to blast back or worse yet the hammer to be blasted back upon firing.
If I were you, I would evaluate the factory nipples on the gun. If you find caps that fit properly and you are not getting blow back that causes cap jams or the hammer to rebound, leave them alone for now.