elderly Centennial has an ignition problem

[biggyfries]

I just aquired an elderly Centennial number 41xx with flat latch, it won't fire reliably due to a light hammer strike SOMETIMES. (it will fire three or four shots per cylinder) Also the firing pin strikes slightly off-center sometimes. I hope this is something others have found before and can help me diagnose. The hand appears to be perfect.
I have disassembled it and found someone has tried to do a trigger job, and I can see some filing/polishing marks on the sear, and also on the cylinder stop. The cyl stop appears to be working well enough, but I am puzzled by the apparent filing/polishing of the upper surface. It tracks around the cylinder quite well--its just puzzling.
I don't know if the springs have been shortened or lightened, but I suspect they are--some one may have clipped off a loop or two so I propose to buy some Wolff springs (shooter's pak) and see if that helps.
I am semi-knowlegable, but I find it is always good to inquire of someone with greater knowlege--any other suggestions in addition to trying new springs?

[Injunbro]

Way too many people go about an action job backwards by cutting or lightening the mainspring first (since it's the easiest). Then after they get the trigger pull pretty light they start tinkering w/ the innards (where they should have started in the first place) & wind up w/ a situation like you have. I'd bet new springs will fix it. The pin that holds the firing pin to the hammer might be worn & sloppy (rare but it happens). I believe your Centennial was made around 1952.

[biggyfries]

Thanks for the info Injunbro--here is the newest puzzlement:
I bought Wolff springs shooters pak and installed the strongest springs and went out to test fire it, and there is no appreciable improvement. The trigger pull feels better but the primers are being struck way off center, and in a few cases the firing pin is actually hitting the brass slightly!
I looked at the hand and checked the gears(?) that the hand bears on at the center rear of the cylinder and they look good and when compared to those parts on some of my other old S&W pistols they don't seem to have any unusual wear. I looked at the cylinder stop and it has a flat shiney spot at the top edge of it, but there is no undue wear or loose fit. If all these parts are looking pretty good, then why would I get firing pin strikes so far off center of the primer? How might I correct this issue?
PS--the tip of the firing pin shows signs of being 'stressed'. It seems the firing pin is not looking pristine, the tip protrudes far enough to hit the primer sufficiently, but it has a slight flat spot on it as if it hit something hard sometime in the past.

Suggestions?

[Injunbro]

How much gap is there between the crane & frame? It's possible it's bent (usually caused by a knucklehead snapping his wrist to close it).

[Crazybastid83]

sounds like it is out of timing no?

[DocZeus]

FAQ

Check Post #16 in the above-linked FAQ.

DocZeus
AKA
David

[Tyrod]

Prolly needs new points, condenser & plugs.