FWIW, (and I'm certainly no expert) my first thought would be a firing pin damaged by someone dry-firing this one.

The gun doesn't appear to have been shot enough to have any kind of significant wear issues. It is certainly possible that it is just gunked up with powder residues, that also seems unlikely based on its overall condition. It just doesn't look like it has been shot enough for powder fouling to be an issue.

So to me the most likely and logical explanation for the light strikes would be a mechanical issue. I'm thinking firing pin damage due to dry-firing.

S&W and pretty much every other manufacturer advises against dry-firing their 22LRs because of the potential for damaging the firing pin. So that would be the first thing I'd suspect.

JMO and YMMV...

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