[drgoose]

When cleaning my 22LR conversion kit for my Sig P226 I saw what I think is the impression of the firing pin on the back of the breech. Is this impression supposed to be there?

 

[airhead]

looks like the typical rimfire/dryfire syndrome.

Dryfiring rimfire weapons will cause the firing pin to strike the breech, leaving a small scar.

Only real worry is damage to the firing pin.

Don't dryfire rimfire weapons. Use a snapcap or old brass.