Extended firing pins bad?

olympicmotors · Mar 16, 2020

For years I have read about people installing extended firing pins in weapons they have done trigger jobs on to lighten the pull. It seems logical an extended firing pin would be extra insurance against a light primer strike. I really can think of no downside. What am I not understanding about this?

ContinentalOp · Mar 16, 2020

It's possible for an extended firing pin to pierce the primer and get stuck, tying up the gun. Even if it doesn't get stuck, the hot gases from inside the case can escape through the pierced primer and, over time, erode the firing pin and/or the firing pin bushing. Depending on how powerful the load is, it may cause injury to your hands, though I think with most handgun loads that is probably a low probability event.

Protocall_Design · Mar 16, 2020

A lot of Smith revolvers came from the factory with firing pins too short or just barely long enough to set off a primer unless the hammer had a very heavy strike force. The extended firing pin solves that problem by giving a bit of leeway for tolerance stacking.

For example, a firing pin just barely long enough to work on a gun with tight endshake can start having problems if more endshake develops. Or if someone is shooting reloads where the primers are .005 to .010 below the head of the case (most of them are). Or if the gun has a few thou. too much headspace. Or the rim thickness varies on different kinds of brass, etc., etc.

In my experience, an overall length of .495 is the minimum that will be reliable most of the time. I prefer .500 to .505 for mine.

Some people worry about getting pierced primers on hot loads (magnums), but I have never had that problem. That may be possible, I don't know from personal experience.

BC38 · Mar 17, 2020

Well, FWIW, I have an old commercial 1917 that has had the cylinder reamed deeper to chamber 45 Colt. Since it is also cut for 45 ACP with moon clips, whoever reamed the cylinder also installed a slightly longer hammer nose to insure reliable ignition of the 45 Colt rounds - which have a little forward-backward "wiggle" (a.k.a. excessive headspace).

Works quite well, though it does just barely pierce the primer cups of some brands of 45 ACP rounds - just enough to leave a trace of soot in the dimple.

Doesn't seem to be causing an issue, but of course since both the 45 ACP and 45 Colt rounds are relatively low pressure it isn't like there's a blowtorch of hot gasses trying to come through the barely pierced primer.

BLUEDOT37 · Mar 17, 2020

I bought the re-introduced 610-3, when it came out, & I decided to forego my usual testing routine & installed a C&S extended firing pin in it before taking it to the range, even though the factory firing pin measured a not too awful .490".

At the range, firing my usual 10mm auto handloads, I started having issues with not being able to SA cock the hammer after having just firing a round. I finally was able to see what was happening, the firing pin was sticking in the primer occasionally & not releasing quickly prohibiting cylinder rotation & cocking.

Deciding it had to be the C&S, even thought I never had any related issues with one, I put the factory firing pin back in & haven't had that problem reoccur since, even after re-chambering it for 10mm MAG.

Many of my revolvers have one in them, & other than this, they've never caused any issues. I don't have any reservations installing one if one is called for.

.

dr. mordo · Mar 17, 2020

Conversely, I had a M325 NG that was not reliable even with stock components. I tried new stock springs, still failed to ignite quite often.

I got a Apex XP extended firing pin, still unreliable.

I finally got a C&S extended firing pin which fixed the problem. I then went to reduced power springs and still had total reliability.

After I swapped for Wilson springs, my M629 Deluxe had some ignition issues as well, though not nearly as bad as the M325 NG. C&S firing pin fixed that one, too.

I have never had an issue with the pin getting stuck in the primer, even with my moderate 44 Mag handloads. By moderate, I mean significantly hotter than a 44 SPL but not max load for a magnum.

I'd give your gun a trigger and spring job and test fire it. If you have ignition issues, buy a C&S pin.

Or, just spend about the same money and buy an older gun with an external firing pin. Problem solved. Plus you get nicer bluing, a case hardened trigger/hammer, and no lock.

robertrwalsh · Mar 17, 2020

They are only bad if they are unnecessary. They are great if they are needed.

zzclancy · Oct 26, 2020

Apex firing and spring.

I installed an Apex firing pin and spring on my S&W 21-4.

I have done the lock delete from JD. I also had bobbed the hammer.

I when down one pound on the trigger return spring an on occasion I have had a few light strikes with Winchester primers.

Trying to get to the range this week to try it out.

Any more comments from anyone else on Apex firing pins?

Seadragon · Oct 26, 2020

zzclancy said:
I when down one pound on the trigger return spring an on occasion I have had a few light strikes with Winchester primers.

The trigger return spring will affect both single and double action trigger pull but has no (i.e. ZERO) affect on how hard the hammer hits the firing pin. If you are experiencing light strikes it is not because of whatever trigger return spring you are using. As long as the trigger returns properly after firing the trigger return spring is strong enough.

ms · Oct 27, 2020

Downside is that in a rimfire, you will almost certainly dent the cylinder if you dry-fire.

Extended firing pins bad?

olympicmotors

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