Firing pin?

gatchelguy · #1 10-21-2013, 08:30 PM

I got a new 642-2 three weeks ago. No problems, but I'm curious about something. How far should the firing pin protrude through the breech plate during operation? Min/max?

Big Cholla · #2 10-23-2013, 10:23 AM

Far enough to hit the primer and cause ignition. But, it MUST retract below the surface of the recoil shield every time after ignition. ........... Big Cholla

ps: for a good check of hammer/firing pin strike, take your revolver and unload every chamber. Cock the hammer to the single action position. Also will work double action; it just takes more dextarity on your part. You have to drop the pencil in after the cylinder rotates to the firing chamber. Take a pencil with a new eraser head and place it eraser end down into the barrel. Aim the revolver straight upward. Pull the trigger. The force of the firing pin strike should send the pencil out of the barrel and upward a few feet above the muzzle. For eye safety don't use a sharpened pencil............don't ask me how I know this. .... Big Cholla

gatchelguy · #3 10-25-2013, 10:59 PM

Quote:

Originally Posted by Big Cholla

Far enough to hit the primer and cause ignition. But, it MUST retract below the surface of the recoil shield every time after ignition. ........... Big Cholla

ps: for a good check of hammer/firing pin strike, take your revolver and unload every chamber. Cock the hammer to the single action position. Also will work double action; it just takes more dextarity on your part. You have to drop the pencil in after the cylinder rotates to the firing chamber. Take a pencil with a new eraser head and place it eraser end down into the barrel. Aim the revolver straight upward. Pull the trigger. The force of the firing pin strike should send the pencil out of the barrel and upward a few feet above the muzzle. For eye safety don't use a sharpened pencil............don't ask me how I know this. .... Big Cholla

I did the pencil test. It barely moved (1/4"). I tried with 3 M10's, a M37 and an Official Police. None would kick the pencil out of the barrel and all have original springs. I emailed S&W and am awaiting a reply.

Big Cholla · #4 10-25-2013, 11:26 PM

Well I'll be darned! Neither will my S&Ws. While all of my Colts send that pencil flying. Three S&W revolvers would only get about 3/4s of an inch. My J Frame only causes the pencil to bounce a little. I guess that is one "Test" that just doesn't transfer well from one brand to another. After years of working on mainly Colts, it is one of those things that I had to relearn today!...........Sorry for the misinformation. My bad. ........ Big Cholla

KLYDE · #5 10-26-2013, 06:55 AM

Unless you are getting misfires / shallow hit primers, I wouldn't worry about it.

hotrod150 · #6 10-26-2013, 09:54 AM

Ditto on the misfires. "Dear S&W, my model 642 won't shoot a pencil...". Really? I admit that this USED TO BE one of my quick-and-dirty gun tests, until I tried it with my j-frames using both stock full power mainsprings as well as 8-pounders & got the same results as you two.
Gatchelguy, if your 642 works OK my suggestion is don't go looking for trouble.... if it's not broke, don't fix it.