Loose 1911 Firing Pin Stop


January 14, 2005, 11:17 AM
Awhile back I picked up, at a used book store, a copy of Troubleshooting your Handgun by J.B. Wood. I believe it was published 20-25 years ago. In the chapter on the 1911 he mentioned witnessing a blow to the hammer of a 1911, with a loose firing pin stop, that caused the gun to discharge. It appears that the loose stop allowed the firing pin to move enough to ignite the primer. Have any of you heard of this? With all the talk of firing pin stops the past few days I thought I would through this out for discussion.

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Black Snowman
January 14, 2005, 12:12 PM
That would have to be one heafy blow to the hammer and it's a gun with no firing pin safety the condition of the FP stop would be a minor factor. The bigger one being the strength of the firing pin spring and the strength of the blow. In a gun with a firing pin safety it would also reqire that to fail as well.

This is one of the reasons C&L is safer in a 1911 than hammer down on a round, particularly in guns with no FP safety. With the hammer cocked you have to break the seer or hammer hooks and get past the "half cock" notch before the hammer can get close enough to strike the FP. Then it still needs to strike with enough force and if it's has a FP safety that has to fail as well.

In the origional JMB design a stout blow to the hammer in Cond 2 BETTER set the gun off or somethings wrong with your FP ;)

January 14, 2005, 01:04 PM
He said that it discharged when the person, while at a picnic, attempted to catch a large soft drink bottle and it slipped through his fingers and hit the hammer.

Old Fuff
January 14, 2005, 01:18 PM
The bottle might have hit the pistol, but not the firing pin. The back of the firing pin and firing pin stop are shrouded by the slide, and the slot in the back is only wide enough for the hammer.

"IF" the bottle knocked the gun out of his hand (or where ever it was) and it fell muzzle-first on a hard surface, and "IF" the firing pin spring was weak, the pistol might have fired. But this would have nothing to do with the firing pin stop.

I think something in this story is missing ... :scrutiny:

Most if not all USGI 1911 and 1911-A1 pistols had firing pin stops that were a slip fit, this to insure easy disassembly. Over a 75 year time spread - and still running - no problems were discovered that required any change.

January 14, 2005, 01:24 PM
Old Fuff, I will read the article again tonight. I am posting from memory and it ain't what it used to be. :).

January 14, 2005, 06:49 PM
Under certain circumstances...possible. The hammer would almost have to be
off the firing pin stop and the spring would have to be seriously weak...and the blow would have to be heavy for it to happen though.

Some mainspring housings are slightly out of spec, and dont allow for full forward hammer travel...or the hammer strut is bit short, and the hammer doesn't come to full rest on the stop...or even has a little play. If the hammer isn't touching the firing pin, or is just barely touching it...it's slightly possible that a hard blow to the hammer could drive it forward with enough force to overcome the firing pin spring and let the tip of the pin light a sensitive primer...such as a round of Federal ammo...known to have primers that are a little touchy.

I've run into tolerance stack issues that prevent full hammer travel, and actually leave the hammer flopping when fully down. If the housing is located
a little low in the grip frame...and the cap itself is a little too tall with its travel limited by hitting the cap retaining pin...which may also be located slightly low...AND the strut is on the short side of tolerance...all these little things stack up the wrong way and you can have a hammer that sits as much as .050 inch off the firing pin stop. In a case like this, a strong blow to the hammer could conceiveably fire the gun, especially if the firing pin spring is also weak or on the short side of spec.

Note that these dimensions can be within acceptable tolerance, but when they all come together in the same pistol, they add up to the whole system
being out of spec.

So...Yes. It could happen, though the chances would be low. "Course...
people get bitten by sharks and hit by lightening and even win the lottery
sometimes... :p

Old Fuff
January 14, 2005, 08:34 PM
Gary ....

My memory is perfect ...

Now what was this post supposed to be about ...?? :evil: :D

January 14, 2005, 10:09 PM
Dang! Fuff just jarred my memory.

No. A loose firing pin stop wouldn't contribute to an unintentional discharge.

January 15, 2005, 08:10 AM
No, it would not. If the hammer is fully down then it would have to be a pretty good whack to the hammer and a weak firing pin spring or overly long firing pin to discharge a round in the chamber. If the firing pin is long enough, the hammer down carry could put the firing pin tip on the surface of the primer, then a good hit to the hammer would ignite the primer.

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