Misfire on one cylinder

[test drive]

got an old high standard sentinel .22 lr that has started occasionally misfiring on one chamber. I’ve cleaned it over and over with particular attention to that chamber and can see nothing that stands out and seems to happen more often but not limited to double action fire. The round in that chamber seems to have a somewhat lighter strike indention when that happens. Have tried different ammunition also. Any ideas?

 

[98Redline]

I will assume you have tried different ammo with similar results.

Is it possible that the cylinder is not indexing properly on that particular chamber, causing the misfire?
What do the firing pin marks look like on the chambers that fired correctly vs. the one that light strikes? I would be more interested in where the firing pin struck the case between the problem chamber and the others.

It could also be a weak hammer spring. Possibly right on the hairy edge and one chamber reamed just a hair deeper than the others.

 

[whughett]

The repeating on just the same cylinder would, IMO, indicate that the round is setting deeper in the chamber or is moving forward with the firing pin strike.

 

[joed]

Look at the cylinder stop for that chamber. Sounds like it isn't locking up properly.

 

[Jimster]

Check your plug wires......sorry. Misread that.

 

[test drive]

Yes tried different ammunition, and yes when it happens it shows a some what lighter strike but it does strike and in the same pattern as the fired chambers. Doesn’t miss fire every time. very strange. Index looks correct. I’m thinking shiming the coil spring would fix it but if that was the case I should get multiple misfires. Another thing originaly it was 2 chambers doing it but one cleared up.

 

[walnut1704]

Carefully inspect the chamber where the cartridge rim sits. If it was dry fired on that chamber once too often there might be a slight indentation where the firing pin struck the chamber.

 

[Fleetman]

My money is on walnut1704

 

[RevolvingGarbage]

There could also be crud in that chamber keeping the cartridge from seating fully when you load it. This could also cause light strikes especially with a rimfire.