Sorry about that, Alk8944. I wasn't aware of the staking operation, and to my eye (and my son's) it appeared the bushing had a raised lip at the edge. I understand now that "lip" is instead the staked aluminum frame.
To follow up: I contacted S&W, describing the model and the problem. To my surprise, they sent a paid mailer, so off it went to them. I've just received it back, also on their nickel, saying the parts needed to fix it are no longer available. I'm disappointed, but I can't complain about how they approached this.
It looks as if I'm in the market for a nice, older 10. Sadly, a very nice 10-5 sold at the nearest store about the same time I shipped my 12-3 off to S&W. The search begins...
It will happen with both factory and reloads. With the lightweight frame, my reloads are rather low pressure (low recoil) and are more likely to leave a primer high. The last time I was out, I peered in along the breech face when a case stuck and saw the primer sticking out and contacting right where the lip on the hammer nose bushing was. The cylinder begins to rotate until the primer gets to the edge of the bushing.
It seems I saw a video that Speer made that showed that a primer normally backs out upon firing, then as the main recoil drives the casing back, the primer is reseated.
Does anybody know anything about this? I suppose it would be easy to check out because the primer seated deep would be flush with the surface after being reseated.
.Recoil doesn't drive the casing back.