...came up in some recent thread, so I called all the manufacturers I could think of to find out who made what. Found that M1911A1 (45 Auto) firing pins apparently come in three distinctly different lengths:
* SHORT: ~2.262 inches (Colt, Ed Brown & NHC), the 2.262" being my measurement of a new Colt FP
* LONG: Ordnance Spec = 2.296 - 0.006 inches (Briley, EGW, STI, Wilson Combat & Dawson Precision)
* REALLY LONG: ~2.34 inches (Cylinder & Slide)
The only known manufacturer I couldn't reach was Nowlin.
The surprise was the length reported by a Cylinder & Slide technician who said he measured one at 2.34" with his calipers. The surprising part is that if the C&S ones are really that long and all that extra 0.047" length (over the Ordnance FP) is in the tip, the tip would essentially be flush with the breechface! Edit: And if tolerances stack the wrong way the tip could protrude about 0.009" 0.008"!!
Can anybody out there who has a C&S FP measure it and either confirm or deny the 2.34" length?
Hi Niemis24, Sorry I did not see your post sooner. I can't comment on the C & S FP length other than 2.34" does seem pretty long. But the Nowlin FP is pretty long too @ 2.308. I did call Angela Nowlin and asked her to verify the FP length. She too was at 2.3085-2.309. I have Nowlin FP's in all of my builds and have had no issues. Angela said she's in complete control of Nowlin now and has turned her fathers company back to its roots of quality. She said she builds the FP's just the way her dad did.
Niemis24, probably stating the obvious here but, aren't firing-pins made long so they can be fitted properly?
What are your firing pin fitting procedures and what tools do you use to fit them?
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But the Nowlin FP is pretty long too @ 2.308. I did call Angela Nowlin and
asked her to verify the FP length. She too was at 2.3085-2.309.
That's about 0.016" longer the the average GI FP, which would (if that extra 0.016" is all at the front) put its tip about 0.033" behind the breechface of an average 1911 when the hammer's cocked. That's OK.
Depending on the gun, however, it could protrude as much as about 0.011" when the hammer is down. An in-spec Goverment Model FP tip gets no closer than 0.005" to the breechface when the hammer's down - so maybe the Nowlin's protrusion is important (in a negative sense) if a gun's prone to hammer follow?
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Niemis24, probably stating the obvious here but, aren't firing-pins made
long so they can be fitted properly?
I don't think so. The only one I ever had to fit needed its aft end shortened to compensate for tapering its firing pin stop. Some are about 0.03" shorter than GI specs and (based only on a telephone conversation) only one seems too long. For the most part the old one gets removed and the new one's simply dropped in.
I have measured 3 colt slides from the firing pin port at the breech face to the rear flat. All measured from 2.161" to 2.167".
Add the .134" to .136" thick FPS and I get 2.295" to 2.303".
A firing pin greater than 2.295" OAL will extend past the breechface in the short slide. The longer slide is of course 2.303" OAL.
An easy check is to lock open the slide, then press the firing pin flat against the fps. The firing pin should not extend past the breech face.
For reference I would measure from the firing pin port to the back of the fps.
That dimension is the maximum length for a firing pin in that slide.
How are you measuring? Overall length, or length from the tip to the aft surface of the flange that rests against the firing pin stop?
If would seem to me that the critical length would be from the FPS to the tip. The portion aft of that has to protrude far enough to provide something for the hammer to whack, and should be long enough that there's still something there to hold the FPS when the firing pin impacts the primer. Aside from that, it would seem that there's room for some play in that, as long as the length aft of the FPS doesn't become excessive.
(And then I guess we'd have to argue about what's "excessive.")
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I have measured 3 colt slides from the firing pin port at the breech face
to the rear flat. All measured from 2.161" to 2.167".
The spec for that is 2.170" to 2.178.
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Add the .134" to .136" thick FPS
The spec for that is 0.131" to 0.136".
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and I get 2.295" to 2.303".
The spec for the sum of those two is 2.301" to 2.314", so your measurements for those 3 guns are all below the minimum spec. Note I didn't say the guns were below spec. Here's why.
If the Ordnance slide blueprint is examined closely, it can be seen that the breechface-to-FPS slot distance of 2.178 - 0.008 inches is from a reference line labeled [B]. And [B] is coincident with the breechface only at its top because the breechface slopes back at the bottom by 0°52'. That puts the lower corner of the breechface/FP hole back about 0.011"/0.007" from [B] and (depending on how your measurement was made) may explain why all your measurements are below the minimum Ordnance spec. An Ordnance slide blueprint is available in our Tech Issues section, 14th link down.
Anyhow, the report from C&S that their pin was 2.34" (waaay too long) still intrigues me, but I keep forgetting to call them back. I've a hunch they're not really that long.
FWIW, I measured my Ed Brown 9mm Luger, 38 Super Firing Pin to be 2.290" which is a the low end of the spec limit.
A word of caution to anyone who installs a square bottom firing pin stop then tappers the firing pin stop (FPS) face to eliminate hammer rock. Tapering the FPS will thin it out which may allow a firing pin to extend past the breach face with the hammer down. All the math calculations are nice but one should perform a simple check to prove that the firing pin doesn't extend past the break face when the hammer is down.
I tapered a FPS on a recent build, a lot, not sure how much, but the hammer print finally leveled out right about where I felt it would be mechanically unsound to keep tapering, where it was just starting to cut into surfaces used to seat the extractor.
Anyhow, the firing pin does protrude a bit with the hammer down now, but I can't say I like the idea of taking anything off the back and increasing the opportunity of a FPS drop. I was figuring on taking it off the front, but I can't say I'm terribly concerned for an immediate solution. Anyone who eases a hammer down on a live chamber in a 1911 doesn't know the first thing about operating that weapon. That thing on the side next to your thumb isn't a decock lever.
But I'm not about to pass off my build, still in test firing stages to some buddy at the range either...
I read D&L holds his FPS in place with a set screw. Might not be a bad idea in conjunction with all this FPS filing mania going on here...
FYI, I had to taper my FPS so much I needed to take about 0.048" off its rear end to keep the protrusion at the back the same. It's now only 2.245" long, been in the gun about 5 years, and the FPS has never dropped. If the various dimensions of the back end of the extractor are favorable, the "spring" in the extractor will help keep the FPS from dropping.
When the FPS is slid down a little with the FP against it, the FP on this gun protrudes from the breechface a tad more than 1/16". That's quite a bit and no doubt one reason why the FPS has never dropped during firing - the FPS can't get out that far as long as the cartridge has a primer in its primer pocket.
Unless the pin fully penetrates the primer... Most advice I've seen says to make the FPS a tight enough fit that it wouldn't ever be inclined to drop from gravity alone. I make them a stiff fit, but the machinist in me says light press fits aren't good for much.
I do understand that it's an uncommon malfunction and may require a worn out firing pin spring, which I wouldn't be likely to let happen.