Re: "Not all SIG firing pin positioning pins (FPPPs) are broken by dry-firing without a good snap cap"

I know one or two things about pistols, but I've never heard of FPPPs before. What are they? Can't be the firing pin blocker, because that certainly couldn't be broken by dry firing (it's displaced when the trigger is pulled). I thought inertial firing pins were positioned solely by the channel in which they ride, the firing pin spring, and the hammer.

The firing pin positioning pin is used in Classic line SIG pistols with stainless steel (one piece) slides. It keeps the firing pin in position and from falling out of the back of the slide. In older Classic SIG pistols with formed and welded slides with separate breechblocks, the pin that holds the breechblock in place also serves the same function.

The pins will be shown in any SIG Classic line pistol parts diagram. In this one it’s part number 10.

Thanks for explaining that sigfreund.

You’re welcome.

As an additional bit of explanation of what happens, the parts diagram I linked shows that the firing pin has a couple of notches. The forward one is what the FPPP or breechblock retaining pin fits into and that’s what keeps the firing pin from falling out of the back of the slide. If there’s nothing in the chamber to stop the forward motion of the firing pin when dry-firing, then it’s stopped when the rear of that notch strikes the FPPP or retaining pin. The repeated impact of the firing pin is what causes the damage.

On hammer guns I just cut in half a foam ear plug and put one of the halves in front of the hammer to act as a cushion .

I use 'em, specifically Tiptons. Peace of mind, at least with what little piece of mind I have left.

Or just use a foam earplug in front of the hammer. Cheap and quiet.

Shattered a firing pin in my 92FS Inox once, so yeah, I use them in just about everything. A-Zooms, but even those are prone to rim wear after a fair number of chamberings.

If you’re a fan of the earplug method, I urge you to actually test its effectiveness.

As an experiment, I put half of an EAR foam plug under the hammer of a P250. After 30 dry-fires I used the pencil-in-the-barrel test to see if the firing pin was completely blocked. The pencil (actually the plastic tube from a Bic pen) was driven up about a foot. That’s a lot less than without the piece of foam under the hammer, but it’s not as effective as the O-ring method.

quote:

Is it necessary to use a snap cap to keep the firing pin from crystallizing?

That's the first I've heard it put that way.

quote:

Originally posted by Jumper:
Shattered a firing pin in my 92FS Inox once, so yeah, I use them in just about everything. A-Zooms, but even those are prone to rim wear after a fair number of chamberings.

I use A-Zooms in my P238, and my 9mm X5. I load them from a magazine and the rims stay nice. But if you put the snap caps directly into the chamber, the rims will get buggered up by the extractor as it rides over them.

quote:

Originally posted by sigfreund:
If you’re a fan of the earplug method, I urge you to actually test its effectiveness.

As an experiment, I put half of an EAR foam plug under the hammer of a P250. After 30 dry-fires I used the pencil-in-the-barrel test to see if the firing pin was completely blocked. The pencil (actually the plastic tube from a Bic pen) was driven up about a foot. That’s a lot less than without the piece of foam under the hammer, but it’s not as effective as the O-ring method.

I usually use a whole earplug and haven’t had that problem.

Cheap insurance imho.

Sometimes when I need to round up to a certain dollar figure with brownells to use coupon codes or free shipping, I toss in a baggie of snap caps.

Very cheap insurance and can also be used for failure drills at the range when they start to wear out.