SAA recoil shield problem

[smle-man]

My 1990s vintage Uberti SAA has an issue with a ridge forming around the firing pin hole on the shield. This ridge in conjunction with two chambers that are slightly shallower than the other 4 makes the revolver very difficult to cock once the rounds in those two chambers are fired. The ridge drags on the fired primers. It has happmed twice now. Both times I've used a fine grade file to remove the ridge. It takes a couple hundred rounds for the ridge to form. This is something that started about 10 years ago. What is causing the ridge? I don't dry fire the revolver.

[Pardini]

Is the firing pin hitting it?

[ojisan]

Does the firing pin move up and down in the hammer?
Maybe even has some side to side play?
Many guns have some wiggle room here to compensate for any misalignment between the firing pin and the hole in the recoil shield.
Even if you don't dry fire, the final amount of protrusion of the firing pin is usually set by either the hammer or firing pin striking the frame.
Best is for the hammer to strike the frame, but many guns stop on the pin.
Sounds like yours is stopping on the pin.

If the firing pin is a rigid design then you might have some misalignment between the firing pin and the hole.
The best fix is probably to have the firing pin hole bushed solid and then re-drilled in the exact right spot for no contact with the firing pin.
Could be expensive.
It may just wear itself in and then stop wearing after more use, until then you will have to clean up the moving metal.