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Firing pin question

Posted: Thu Feb 13, 2014 4:04 pm
by AllGator
I'm an IPSC, USPSA and IDPA shooter. I'm coming late to the rimfire party: So, please pardon my noobie questions/ignorance. Failure to fire seems to be an universal concern...most commonly seems to be blamed on the ammo.

All of my center-fire pistols have reduced power main springs and lightened hammers. To help offset the loss of strength of primer strike, extended firing pins have been installed. In a Ruger rimfire pistol, if one were to remove .005 or so from both the rear of the firing pin stop hole and the fin that engages the firing pin rebound spring, it seems to me that would be equivalent to an extended firing pin.

First, is this something that others do with 22/45's? If so, how effective is it? Finally, other than the loss of the ability to dry-fire, are there other potential negative effects?


Posted: Thu Feb 13, 2014 4:52 pm
by Bullseye
Removing material from the back/extending the firing pin of a rimfire pistol is not a good idea. A rimfire pistol needs clearance between the firing pin and the chamber mouth. Any extension on either end brings a greater chance of the pin striking the chamber mouth during normal operation. There's very little tolerance between the chamber face and pin head as it is, the factory clearance tolerance also takes into consideration stretching of the pin over the lifetime of the part. The more use a rimfire pistol has the greater the stretching can grow to be, no need to lessen the gap by extending the firing pin and increasing the potential of a chamber strike.


Posted: Thu Feb 13, 2014 5:06 pm
by stork
I'd advise paying heed to Bullseye's recommendation.

Dud's on 22 ammo usually comes from a lack of priming mixture under the firing pin hit, or a chamber/bolt face area so filthy that it cushions the round instead of holding it solidly. Normally if you remove the 'dud' and turn it a bit it will fire with the next hit. An extended firing pin will not help this issue if you're shooting a 22 that is even close to clean.

I could see this going badly really fast, but in the end it's your pistol and your decision.


Firing pin

Posted: Thu Feb 13, 2014 8:06 pm
by AllGator
Thanks to both of you. I think you fully answered my first question: No, it's not done. Unfortunately, that means there is no data available about effectiveness...or lack thereof.

Let me put in a little disclaimer here: I am working with a pistol that is meant solely for competition and any such mods/changes would not be recommended for a casual shooter or a "working" pistol. Or a pistol which you would not like to subject to potential damage.

Bullseye, I'll try to explain a little better: I have two other rimfire pistols (a High Standard M106 and a CZ Kaydet) both of which are designed to allow their firing pins to contact the breech face. Most importantly to me, I have no problems with failure to fire with either of these pistols. My thought was that if I modified the Ruger's firing pin stop system to allow such contact it would improve it's rate of failure to fire frequency. I do understand that such unrestricted contact (ie, dry firing) would peen the chamber and essentially ruin the pistol for use.

Stork, in the past four months of practice/competing I came to fully support your position 100 per cent! Dirty chambers impede chambering; block full bolt closure; and, cushion firing pin strikes. But a match is a minimum of 150 rounds and some build up will occur. My thought was that a longer firing pin strike would not loose all/most of it's energy in a final seating of the round. Therefore, there would be more residual energy available to hit/crush the rim.

I really appreciate your recommendations and cautions. I guess I will order another firing pin (in case things do go wrong), try the mod, and gather some results. I will report the results...positive or negative. Particularly any breech damage. The only dog I got in this fight is wanting the thing to go "Bang" every time.


BTW, I just installed a 10% stronger (progressive) variable rate Wolff recoil spring. Something else from my center fire experience. Any comments about that?

Posted: Fri Feb 14, 2014 9:06 am
by blue68f100
Remember on a Ruger you have to do a dry fire in order to take it apart.

Posted: Fri Feb 14, 2014 9:26 am
by stork
blue68f100 wrote:Remember on a Ruger you have to do a dry fire in order to take it apart.
Good point Blue, I totally spaced out that little tidbit.

Posted: Fri Feb 14, 2014 9:31 am
by AllGator problem: Holding the bolt, let it close about 1/2 to 2/3's of the way; pull the trigger to release the hammer; then, slowly let the bolt close. The hammer will follow the bolt down without the firing pin hitting the breech face.

Or you could just use a snapcap or dry-wall anchor.


Posted: Fri Feb 14, 2014 9:59 am
by AllGator

BTW, thought I might amplify the comment about cleaning the chamber and bolt/chamber interface. After each match or practice session I field strip the pistols (yeah, now I have two) and use a 6mm bronze brush chucked in a hand drill dipped in Hoppe's. Run it only in the chamber at moderate speed for about 10 to 15 seconds...voila! have a very clean, clean chamber. The bolt is disassembled (but not the extractor) and wiped clean. What?...this takes a total of about five minutes for each weapon. I really don't relate to the many posts in which the shooter indicates that they clean their pistols only after thousand upon thousands of rounds. And, No...I don't suffer from OCD.


Posted: Fri Feb 14, 2014 11:56 am
by Coach1
Hi A-G. Welcome to the GTO forum. You will get no OCD disparagements about keeping a firearm clean from this group. I for one will follow this thread and your subsequent posts with interest. But, admittedly, I will not ever consider such a mod to my Ruger 22/45. Please keep us informed.. good, bad, ugly ... whatever.