Sparks from firing pin while dry firing?

B

BigD_in_FL

Moderator
Question for those who dry fire

Little minor surgery on the shooting wrist, so I was practicing with my off hand (unloaded gun of course) while looking in the mirror to see how well I kept the muzzle under control I was noticing a small spark when I pulled the trigger.

This tells me that I have metal on metal contact - question is thus

big deal needing attention? or, nothing to worry about

Thanks
 
Sparking like this is a phenomenon of some guns with frame mounted firing pins.
Charter Arms was famous for this, and I think some S&W's also did it.

I forgot what the reason was, but the factories said it was not an issue.
 
The spark you see, whether from dry firing or from a grinding wheel, is a piece of hot metal flying off.


how much metal can you spare?

Bob Wright
 
I would like to hear more about this. I am wondering how sparks could occur from the contact of the hammer. I'm an old muzzleloader and have used flint and steel many times to make sparks, but this requires the flint to shave off carbon from the steel. Very interesting phenomena from a revolver...
 
Hot metal flying off? Probably not. The phenomenon is due to the rapid compression and heating of the air in the firing pin chamber igniting oil or gun cleaner. There have been guns designed (including one patented by a fellow named Sam Colt) that used air compressed by the hammer to ignite powder without using a percussion cap.

Jim
 
^^ This

This is also not the first time this topic has come up. Someone posted a video of it happening on youtube one of the last times someone could probably find it.
 
The video link by FrankenMauser shows it pretty well. You have to have a closely fitted firing pin that will act like a piston and a small firing pin hole. Both conditions are met in those guns. Sometimes you can even hear a tiny "pop" as the oil ignites.

Jim
 
This is a J frame 38, new, and was only noticed when looking at the muzzle in the mirror
Click to expand...

Interesting? So. if the firing pin is dragging hard enough to cause a spark, I bet that it is dragging enough to bleed off spring pressure and possibly cause a miss fire?

A comment was made that this spark might be the result of carbon burning. I would offer another possible cause. I have recently seen fire starters that rely on compression to ignite kindling: http://en.wikipedia.org/wiki/Fire_piston
Could your firing pin be acting like a fire plunger, igniting the carbon building up between the firing pin and the recoil shield?
 
Thought I'd heard it all in 50+ years of shooting...sparks from the firing pin area...and the suggested cause being compressed air from the firing pin channel igniting cleaning residue or carbon build up...too, Sam Colt's attempts to get a cap & ball revolver to fire successfully without a percussion cap.

All good answers...I guess that you learn something new each and every day, if you listen!

Just a thought as to the other cause: if the hammer/firing pin is in fact shaving metal during hammer fall, the results should be obvious on close inspection. A call to S&W customer service, would be instructive...how 'bout a repost on your results after calling S&W...I'd be very interested to hear their response.

Best Regards, Rod
 
You do indeed learn something new everyday. My 642 does this. As it's been dry fired a lot, and shot a lot with zero issues, I'd say this is a non issue.
 
I couldn't get mine to do it last night. It may be too clean, too dirty, to dry, too oily. Or, it may have been dry-fired too much, since it was last shot (it's been a long time). Who knows...
 
Hi, rrruger,

The piston (in this case the firing pin) doesn't have to be absolutely tight, only tight enough that the combustible mixture can't escape fast enough to keep from igniting. Of course, the most common use of ignition by compression is the Diesel engine, which has no spark plugs;* compression heats the air past the fuel ignition temperature before the fuel is injected into the cylinder.

*Some diesel engines have glowplugs to aid starting in cold weather.

Jim
 
My gun does this also

I have a Smith Model 640-3 (2010 vintage) that throws sparks from the firing pin hole. I have owned the gun for about a year and bought it new. It sat at the bottom of the dealer's safe for a couple of years is the story that I was told.

Anyway, the gun functions as it should and is accurate with .38spl loads. I haven't fired .357 rounds in it yet. So, I have no desire to call S&W customer service. I do worry, however, that I may be chewing away small particles of my firing pin every time I fire the gun.

I am glad to have found this thread.
 
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