Occasional failure to fire

[Revolvr]

Hi all! I am looking for a bit of sage advice on solving a problem. I have a 1920's commercial .30 Luger I recently bought.

It loads fires and ejects flawwlessly - except for one minor problem.

Occasionally I pull on the trigger and nothing happens. The sear surfaces apparently do not disengage. If I pull the trigger again (maybe a few times), it will fire.

So my theory is that perhaps there may be just a bit of play between the firing pin and breechblock so that it might move just a bit with the sear bar as the trigger is pulled. Or possibly the engagement surfaces are a bit rough and it has trouble disengaging.

Another possibility is the sear bar was not an original part and needs a bit of fitting. All parts have matching numbers but there is no number on the sear bar. Should there be?

So I am thinking I could lightly stone the sear bar (the ramp) and ever so slightly radius the edge. I have done some trigger work on other guns so this isn't completely new to me.

But I would like to know if anyone else has seen this problem, and am I on the right track?

Thanks much,

-- Dan