QX for Gunner

Gunner,
A friend brought me his Walther P-22. Said it won't reliably fire cheap bucket-o-bullets rounds.
It won't.
I have never worked on a P-22, but it looks like it's got a boss on the
firing pin to prevent the pin from penetrating the rim of the cartridge. On cheap, thin rounds, it looks like the boss is striking the breech before the pin penetrates far enough to pop the primer.
Question: Can I grind off four or five thou from that boss without otherwise harming the purpose of it? Or is it so critically adjusted for length that any change will end up perforating rims?
Thanks,
LLoyd
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On Tue, 31 Jul 2007 09:44:35 -0400, "Lloyd E. Sponenburgh"

It has been a long time since I was a gunsmith but I never saw a .22 rimfire firing pin that had any sort of "stop" built into it -- this is not to say that things haven't changed since I was in the business but why not mic some quality ammo rims and some "bucket of bullets" rims. That should tell you right away if rim thickness is the problem.
Bruce in Bangkok (brucepaigeATgmailDOTcom)
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It has a stop: The pin is "T" shaped, with the vertical leg being the rim-striking portion, and the top of the tee a larger block that impinges on the side of the barrel, to prevent over-penetration (I guess).

Did my description, "cheap, thin rounds" go wasted? <G>
CCIs are about 4-thou thicker in the rim than the Federals that fail.
LLoyd
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Without a picture we can only guess, but are you sure the part that impinges on the barrel isn't the result of the firing pin being peened down by the barrel edge, as a consequence of excessive dry firing? I've seen a couple of cheap .22 rifles that had a blade-edged firing pin that had been peened badly. One of them was one that I owned as a kid...
-- Ed Huntress
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Actually, it's pretty clear upon looking again, that this boss is NOT for the purpose of preventing rim perforation -- I even doubt the hammer spring is stiff enough to do that. What it's for is to absorb the hit when the weapon is dry fired.
The actual firing edge of the pin would clear the barrel edge by a few ten-thousanths in the ideal. Actually, it clears by about six thou... which still shouldn't explain why the Federals (and bucket Rems and bucket Wins) won't pass 80%.
I'm wondering if the pin end needs to be sharpened up a bit to increase penetration into the rim, then shorten the boss if necessary.
I don't have a brand new pistol in front of me to check the geometries, but this one is only a few years old, and in really well-kept condition. There is a small wear mark on the barrel edge indicating that the stop boss is doing its job.
LLoyd
LLoyd
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On Tue, 31 Jul 2007 13:26:30 -0400 in rec.crafts.metalworking, "Lloyd E.

You don't want penetration of the rim. You don't want it sharp. You want crushing of part of the rim.
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wrote,

I didn't mean "penetration" in the sense of cutting the metal. Only that it now leaves only a light impact mark -- considerably more shallow than the 22 r.f. weapons I own. Decreasing the impact area a little will increase the force over that area, hopefully resulting in a deeper hit (increasing - I hope - the likelihood of crushing the prime enough to fire the round).
Other owners of the P-22 have complained about its being fussy about ammo brands. Basic design flaw, most likely. One might even suspect the strength of the pin spring itself. Not enough isn't good, but too much, and more of the hammer force is lost just overcoming the spring.
LLoyd
LLoyd
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Keywords:

The geometry used for many .22 firing pins is a relatively narrow blunted chisel shape. However, that only works if the firing pin can't rotate. The chisel shape gives good crushing impacts even with a weak hit. The tip of the firing pin on my Benelli pistol is about 3/32" long and about 1/32" wide, with a slight radius on the edges to avoid cutting through the brass.
There was a discussion in an article in Precision Shooting magazine about the optimum geometry, which I believe included a slight bevel on the chisel point so that inside edge wasn't quite as deep as the outside. I think the theory was that this helps to direct the primer explosion inward towards the powder charge.
Doug White
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On Tue, 31 Jul 2007 12:28:05 -0400, "Lloyd E. Sponenburgh"

I guess cost effectiveness arrived while I was gone, at least I assume that the cheap stuff is made of thinner brass to save money. If the firing pin is made as you describe then trimming the "stop" should cure the problem.
From your description if is difficult to visualize just how this thing works. You describe a tee with one side of the tee acting as the actual striker and the other side of the tee striking the side of the barrel?         Strikes primer i.e. -----------------------| [[[[[[[[[[[[[[[[[[[[[[[[[[ barrel         Strikes barrel
Not arguing just asking a question as still some residual interest from the old trade.
By the way, how did California come to decide that a .22 cal pistol was an "assault weapon", as I noticed when reading up on the P22?
Bruce in Bangkok (brucepaigeATgmailDOTcom)
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On Wed, 01 Aug 2007 08:09:14 +0700, snipped-for-privacy@gmail.com wrote:

THreaded muzzel.
Gunner
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snipped-for-privacy@gmail.com wrote:

You never got inside a Ruger Mk1 or MK2 then?
There is a cross pin in the bolt that retains the pin from hitting the chamber edge.
I learned how to iron out a chamber as a result of that little tidbit. :-/
Cheers Trevor Jones
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On Tue, 31 Jul 2007 09:44:35 -0400, "Lloyd E. Sponenburgh"

Yet it works ok with more expensive ammo? Sounds like a timing/battery issue.

I dont see why not. Just make sure the striker has a rounded tip.
YMMV of course. Ive never shot a P-22. They are an "assault weapon" in California.
Gunner
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On Tue, 31 Jul 2007 15:14:07 GMT, Gunner Asch

Be safe in Kalifornia, Gunner! <G> We wouldn't want crazed hoards of lunatics storming your bulwarks with assault P-22's, right? <G>
I've found that some .22 semiautos are fussy about ammo. A friend of mine has a P22, has found that it has definite ammo preferences. It is a fun little pistol. I have a Browning Buckmark, ditto for it. Both pieces are in as-new condition. I once rented a S&W semiauto (probably a 22S) that wouldn't fire anything reliably but it was quite dirty and perhaps clapped out.
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Well for what its worth, my Ruger 22/45 fires all .22's with ease.. Never had a misfire or no fire, no matter the ammo brand (and I am darned cheap too!!) . My Ruger single six has never failed either and its a three screw with a very low serial number. Hundred of rounds through each and they are still accurate and never let me down...... Sorry about the shameless plug for Ruger, but I sure like mine......
bob in phx....
Of course my 1908 .22 Winchester pump does misfire on occasion, but its very old and well worn!!!!!!!! I sure have great memories of shooting that baby!!!!!!
wrote:

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wrote:

The Ruger .22 semiautos are excellent, though a bit of a chore to clean if one worries about such matters. Wheelguns, single-sixes and others, typically fire anything they're fed.
Hundreds of rounds are barely breakin.
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On Tue, 31 Jul 2007 09:44:35 -0400, "Lloyd E. Sponenburgh"

Hi LLoyd,
For anyone still following this I found a parts diagram/pdf file here:
http://www.carlwalther.com/p22t.htm
Direct download:
http://www.carlwalther.com/views/p22.pdf
In all of the misfire cases I have had with .22 rim fires the culprit has been gummy oil/stiction. That being said can all of the related parts move freely? Namely the firing pin, hammer, spring and such. If you have some dry graphite lube I would be tempted to try cleaning all of the contact areas for the firing pin off (so it can rattle around freely) and try firing some test rounds. Too much oil or too thick of an oil may cause trouble too.
Just a little bit of resistance for whatever reason can subtly slow down a firing pin and cause a misfire if it is borderline already.
--
Leon Fisk
Grand Rapids MI/Zone 5b
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