Model 41 Bolt Pin breakage

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tomcatt51

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A friend of mine has a model 41 that keeps breaking the bolt pin (S&W part #065090000). The gun is stock except for a recoil buffer and Wolff recoil spring. Only goes maybe 1,500 rds before breaking the pin (again). Breakage was the same with the stock recoil spring and no buffer. No change.

Common problem? Unusual? Any ideas? Help! This is a bit frustrating.
 
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TOM BECKWITH said:
Never saw one break - collecting and shooting 41s since 1963??????
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This has me baffled. I've replaced the ejector, "tuned" the extractor, adjusted the trigger pull, replaced 2 bolt pins for him and the 3 rd just broke. Someone else had replaced the pin for him several times before I started shooting with him. It's a well cared for, mint looking 41.
 
Double WOW - suggest you contact S&W to see about returning it.
Is it breaking in the middle where the fireing pin cut is? - or random?
Doubt that the pin is MIM. A followup report would be real interesting and helpful.
 
You could have to much end play in the bolt this can brake the pin.If you have movement take the pin and bend it in the center.It will draw the bolt back and you will be OK.
 
TOM BECKWITH said:
Is it breaking in the middle where the fireing pin cut is? - or random? Doubt that the pin is MIM. QUOTE]

The pin is "real steel". You flare one end to retain it similar to a sight windage screw. I haven't looked at this one yet and don't remember where the others broke.

Skip357 said:
You could have to much end play in the bolt this can brake the pin.If you have movement take the pin and bend it in the center. It will draw the bolt back and you will be OK.
Click to expand...
I'll look at that, I don't have it yet to disassemble. It'll be a couple days.

Thanks.
Click to expand...
 
tomcatt51 said:
A friend of mine has a model 41 that keeps breaking the bolt pin (S&W part #065090000). The gun is stock except for a recoil buffer and Wolff recoil spring. Only goes maybe 1,500 rds before breaking the pin (again). Breakage was the same with the stock recoil spring and no buffer. No change.

Common problem? Unusual? Any ideas? Help! This is a bit frustrating.
Click to expand...
---------------------------------------------------------------------------
Tomcatt:
I've seen it on several occassions, and some remedies that have worked for me are:
I always adjust the headspace to achieve .043 which also produces a perfectly flat breechface from surface grinding.
I surface grind the barrel face so the two surfaces, have a full contact mating surface which provides even, full support to absorb the hammer strike.
Next I adjust the firing pin protusion and travel, both fore and apt.
I always increase the aft travel about .020/.025 to give the hammer more time on the pin to help reduce misfires. When checking the forward
travel, I make absolutely sure that the pin is not making contact with the retaining pin when fully forward, as in the hammer strike mode, and surface grind the slot to provide clearance if necessary. Such contact would place the pin under a shear load that will cause it to break. If you do numerous 41s that are seeing a lot of competitive use, it can be beneficial to adjust the back of the breech block so that the frame, and breech block are equal distance. That way the some of hammer strike force is displaced into the frame and saves the pin and reduces the barrelface/breechface battering so evident to all 41's...
Good luck..hope some of this is useful to you..

Jerry
 
tomcatt51 said:
tuned" the extractor, him.
Click to expand...
Tom:

I just noticed mention of the extractor, plus I failed to include it in my other post. The cursed .22 extractor...The clearance/camming radius cut into the barrel breechface is responsible for many of the ills suffered by .22 pistols.
A radius, makes it difficult to exactly time the extractor..when relining the 41, I change the radius to a 35 degree angle and grind a compatible 35 degree angle on the extractor...now the timing/cam out can be exact..solves the extractor problems...
When moving the slide slowly into battery, look for resistance that may hold the slide slightly out of full contact. Even .010 gap..When the hammer strikes, the force is transfered to the retaining pin until the breech makes contact with the barrel face. Repetitive strikes can fatigue the pin and contribute to the breakage you are experiencing.

Jerry
 
JKEEFER, sounds as if you tune 41s and have seen it all. As noted, I had never seen or heard of a broken bolt pin, but apparent it is not uncommon?? In your experience is this common on both older (below A475000) as well as later production. I am aware of quality issues starting around A650000 and the British takeover and continuing since that time - bolt fitting, slide rail breaks, soft metal (bbl face peening with low round count), slide to bbl fit, extractor failures, ejector failures, etc.. Do you tune for the public? Seems like the later production need your expertise.
 
TOM BECKWITH said:
JKEEFER, sounds as if you tune 41s and have seen it all. ------------------------------------------------------------
Hello Tom;
I've seen a lot, but I don't think I seen it all..I keep looking though..As far as problems, I'd have to give it to the A650000 + group. I have high regard for 41's, great gun, and can be made into a super competitive package, capable of record scores..I've used a lot of Shilen & Lilja barrels which have been great shooters... I am trying some Walther liners at present.. Jury is still out on the Walther, I just started to use them; they are turning in some good scores lately.. I am a bullseye smith, and 41's are very popular with the shooters, but alibis aren't very popular, so I was forced to figure out how to make them run...
I stopped taking orders about a year ago.. I just can't catch up..
Take care

Jerry
Click to expand...
 
Follow-up: I finally got the gun to look at. The bolt sits too far forward, held there by the bolt pin. When the slide closes the bolt is pushed rearward against the pin. The bolt face has left it's outline imprinted on the barrel face.

He's going to call S&W monday morning to send it back. Thanks for the help with what to look for. I usually just work with S&W revolvers.

Gun was bought (new) 12-2002. Serail # UBJ0XXX
 
tomcatt51 said:
Follow-up: I finally got the gun to look at. The bolt sits too far forward, held there by the bolt pin. When the slide closes the bolt is pushed rearward against the pin. The bolt face has left it's outline imprinted on the barrel face.---------------------------------------------------------------------------------------------------------------------

Tomcat;

The breechblock has a shoulder/lug at the top which should fit up with zero clearance to the slide. If it doesn't, then, the pin will take the force of the slide going into battery, which is not really that much compared to the hammer strike..This shoulder/lug absorbs the slide in battery cycle force. All 41s, and most all .22s show the breech face outline on the barrel face. It should be uniform/even full contact.. The hammer strike is responsible for most of it.
Jerry
Click to expand...
 
Tomcat;

The breechblock has a shoulder/lug at the top which should fit up with zero clearance to the slide. If it doesn't, then, the pin will take the force of the slide going into battery, which is not really that much compared to the hammer strike..This shoulder/lug absorbs the slide in battery cycle force. All 41s, and most all .22s show the breech face outline on the barrel face. It should be uniform/even full contact.. The hammer strike is responsible for most of it.
Jerry[/QUOTE]
On this gun the lug isn't bottomed in the slide unless the bolt pin is removed. Installing the bolt pin moves the bolt forward "un-bottoming" the lug. I phrased it wrong when I said you could see the bolt face outline on the barrel face, it has beaten (indented) it's outline into the barrel face. With the lug not bottomed the bolt pin is taking all the force of the bolt closing. The bolt pin holds the slide slightly rearward when the bolt is in contact with the barrel face. It looks like a tolerance stacking issue with the bolt pin hole location in the slide and bolt. With the bolt bottomed in the slide, the bolt face is flush with the slide, but the bolt pin holes (in the slide and bolt) are mis-aligned. The bolt pin will not slide in without moving the bolt forward. Hope that makes sense.

I assume in a perfect world the bolt pin would hold the bolt with the bolt lug bottomed in the slide allowing no fore-aft bolt movement in the slide.
 
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tomcatt51 said:
Tomcat;

On this gun the lug isn't bottomed in the slide unless the bolt pin is removed. Installing the bolt pin moves the bolt forward "un-bottoming" the lug. I phrased it wrong when I said you could see the bolt face outline on the barrel face, it has beaten (indented) it's outline into the barrel face. With the lug not bottomed the bolt pin is taking all the force of the bolt closing. The bolt pin holds the slide slightly rearward when the bolt is in contact with the barrel face. It looks like a tolerance stacking issue with the bolt pin hole location in the slide and bolt. With the bolt bottomed in the slide, the bolt face is flush with the slide, but the bolt pin holes (in the slide and bolt) are mis-aligned. The bolt pin will not slide in without moving the bolt forward. Hope that makes sense.
---------------------------------------------------------------------------------------Yes, it does, make sense, and you have most likely found the problem.. Either the bolt, slide, or both are out of spec..
--------------------------------------------------------------------------------------
I assume in a perfect world the bolt pin would hold the bolt with the bolt lug bottomed in the slide allowing no fore-aft bolt movement in the slide.
Click to expand...
Good luck
Jerry
 
Just a follow-up. It came back from S&W with a new slide and bolt. The bolt pin now holds the bolt bottomed in the slide with zero clearance. Thanks for the help.
 
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Here we go again. All is well with the bolt.

BUT when the 5" barrel is installed it doesn't eject. Ejects fine with the 7" barrel.

This is with Winchester and Federal bulk ammo. Are there chamber dimension issues? It leaves the case in or part way in the chamber (5" barrel) while with the 7" barrel it ejects empties just fine, same box of ammo.

This is getting ridiculous. Are 41's this inconsistent or is my buddy just "lucky"? He bought the gun new with both barrels but had never shot it with the 5".

Any ideas?
 
TOM BECKWITH said:
Bulk ammo is just that - not very consistant in all parameters. Go (back) to CCI Std velocity or quality equivalent.
Click to expand...
I understand that (and am going to try some "good" ammo) but it would be nice if it (the 5" barrel) functioned even with inexpensive ammo. The 7" barrel does. He/we shot (or tried to shoot) ammo from the same box(es) thru both barrels. Box of Federal and a box of Winchester. My telescoping gauges don't go small enough to measure the dia. of a .22 chamber (my guess of what the difference is between the barrels) and I don't think my small hole gauges are accurate enough but I'm going to try them. This is a situation where function is more important than absolute accuracy.
 
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