S&W Model 41 problems
John Bercovitz
This is a new pistol, inasmuch as it has had only a few boxes
fired through it, though it was actually purchased just before
the "excommunication". I took it apart because the disconnector-
trigger bar was rough on top and chewing up the lower edge of
the slide. I pulled the hammer out because it was rough (it's a
molded or sintered part of some sort with a few cuts for final
machining). That's when I discovered half the sear notch is
broken off leaving very fine crystalline shapes showing. This
is a brittle fracture. I looked at the sear that mates with
this notch and it has no wear except where the remains of the
hammer's sear notch contact it. So the notch was either broken
as sent from the factory or it broke shortly thereafter. Has
anyone else encountered this problem? I wonder if Numrich/Gun
Parts carries a hammer made cut from solid stock. I'll have to
ask.
I've ordered a new hammer from S&W - ~$50 total. They say the
sear is a "restricted" part, which I guess means it has to be
fitted. I'd sort of hoped to have a new sear also, since the one
that's in there may be uneven. I'll take a look at it, make a
sear block and check it out with Prussian blue - the usual stuff.
The only other problem I've had is an occasional failure to extract,
but I just learned that one is not supposed to dry fire a model 41!
Is there another modern firearm that can't be dry fired? So I then
looked for and found a microsopic dent the firing pin has made in
the breech face and swaged it out. The dent looked too small to be
a problem. However, I'm hoping that was it.
I put some hammer pictures at:
http://www.angelfire.com/ca2/tech3d/M41ham.html
Thanks,
John Bercovitz
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Bob Holtzman
# Is there another modern firearm that can't be dry fired?
Bad practice to dry fire any rimfire. Some have special firing pins
designated for dry firing. Otherwise you run the risk of peening the
barrel face. I did this to an Anschutz free rifle once.
--
Bob Holtzman
"If you think you're getting free lunch,
......check the price of the beer!"
Bob
It's a no-no to dry fire any rimfire, but you can use plastic snapcaps
to dry fire, some pistols like the Ruger MKII/P512 can be dry fired with no
problem, hell after some 20,000 rounds, it may be good for it.
Bob
On Sat, 3 Jul 2004 01:18:30 +0000 (UTC), tloC...@aol.com (John Bercovitz)
wrote:
|>The only other problem I've had is an occasional failure to extract,
|>but I just learned that one is not supposed to dry fire a model 41!
|>Is there another modern firearm that can't be dry fired? So I then
|>looked for and found a microsopic dent the firing pin has made in
|>the breech face and swaged it out. The dent looked too small to be
|>a problem. However, I'm hoping that was it.
Triad Productions-Fantalla(c)~EZine~ParaNovel
National Association of Assault Research
http://triad.naar.be http://rlacasse.naar.be
Bill VH
Bercovitz) writes:
#
#This is a new pistol, inasmuch as it has had only a few boxes
#fired through it, though it was actually purchased just before
#the "excommunication".
-----------snip a line of complaints-----------
Sounds like you were a victim of some cost cutting and foreign
management. I bought a M-41 a couple years before their fall
from grace and had the small spring at the front of the connector
break after a few thousand rounds. Replaced it with part of a small
safety pin, and the pistol is still popping away.
The firing pin is supposed to be restrained by the small cross pin and
not contact the breech face. Thus allowing dry firing.
Basically this one is the same as a short barreled one I purchased in
1960(?). Sometime or other they lost the "loaded" indicator and I've
not missed it a bit.
I regularly get offers from "old guys" to buy my M-41 for what I payed
for it.
Bill Van Houten (USA Ret)
Thermopylae had it's messenger of defeat, COME AND GET THEM !
The Alamo had none.
Henry E Schaffer
#... some pistols like the Ruger MKII/P512 can be dry fired with no
#problem, ...
But be *sure* that the cross pin ("firing pin stop") is in the bolt!
You won't know unless you look, because (I think) everything will still
work fine. The problem is that without it, dry firing will peen the
chamber!
--
--henry schaffer
hes _AT_ ncsu _DOT_ edu
John Bercovitz
Often in these posts I leave out what's most important:
The reason I want to dryfire the M41 is to lower the
hammer when I'm done for the day. I just calculated
the stress in the mainspring when the pistol is cocked
and got 102 ksi; that's a fairly conservative design.
Generally, conservative (spring won't take a set) design
stress for steel spring wire is 104 to 180 ksi depending
on the exact type of wire. Here are my measurements,
in case you want to check my calculation:
material is probably music wire
.267 OD
.047 wire diam
21.7 coils
2.050 free length
1.610 installed length
1.410 fully-compressed (cocked) length
That doesn't sound like a whole lot of stored energy.
Lessee... E = 1/2 K (X^2 - x^2) =
0.5*30*((2.05-1.41)^2 - (2.05-1.61)^2) = 3.2 in-lb
Yup, that's fairly low.
Maybe I'll just put that magazine disconnect spring back in
since it doesn't seem I'll need to decock after dropping the
magazine and clearing.
Thanks again,
John
Stan Schaefer
# Wanted, advice/comments
#
# This is a new pistol, inasmuch as it has had only a few boxes
# fired through it, though it was actually purchased just before
# the "excommunication". I took it apart because the disconnector-
# trigger bar was rough on top and chewing up the lower edge of
# the slide. I pulled the hammer out because it was rough (it's a
# molded or sintered part of some sort with a few cuts for final
# machining). That's when I discovered half the sear notch is
# broken off leaving very fine crystalline shapes showing. This
# is a brittle fracture. I looked at the sear that mates with
# this notch and it has no wear except where the remains of the
# hammer's sear notch contact it. So the notch was either broken
# as sent from the factory or it broke shortly thereafter. Has
# anyone else encountered this problem? I wonder if Numrich/Gun
# Parts carries a hammer made cut from solid stock. I'll have to
# ask.
#
# I've ordered a new hammer from S&W - ~$50 total. They say the
# sear is a "restricted" part, which I guess means it has to be
# fitted. I'd sort of hoped to have a new sear also, since the one
# that's in there may be uneven. I'll take a look at it, make a
# sear block and check it out with Prussian blue - the usual stuff.
#
# The only other problem I've had is an occasional failure to extract,
# but I just learned that one is not supposed to dry fire a model 41!
# Is there another modern firearm that can't be dry fired? So I then
# looked for and found a microsopic dent the firing pin has made in
# the breech face and swaged it out. The dent looked too small to be
# a problem. However, I'm hoping that was it.
#
# I put some hammer pictures at:
#
# http://www.angelfire.com/ca2/tech3d/M41ham.html
#
# Thanks,
# John Bercovitz
#
#
Send it back, there's no reason you should have to fix their screwups.
First I've heard of S&W internals being restricted, but it doesn't
surprise me. New S&W parts are made via MIM, sort of a squirt and
bake approach to making complex parts cheaply. Might be you've got an
example that was over-baked.
I've dry-fired Bangor Punta-era 41s thousands of times with no
problems. There should be a cross pin in the slide that stops the
firing pin from hitting the breech, might be this is bent or out of
spec or the firing pin is out of spec. Might be the new owners opened
up the tolerances, too, and that's why they say not to dry fire it.
If you've done rimfire work before, it's relatively trivial, though
tedious, to stone the tip of the firing pin so it doesn't hit the
breech. Not a job for a tyro, and I wouldn't tackle it without a very
good micrometer, a machine rest and a spare firing pin being
available. A few thousandths too short and you'll get irregular
ignition which will give bad accuracy. If you change the point of
impact on the rim, it can affect accuracy, too.
Stan
John Bercovitz
breechblock retaining pin (06509 bolt pin in S&W parlance) is
supposed to keep the firing pin from contacting the breech face.
Actually, the guy at S&W who took my order for the new hammer
told me the reason dry firing was proscribed is that _some_
firing pins will hit the breech face. That also explains why the
dent in the breech face of my M41 was so light that it was hard
to see: the retaining pin was _almost_ doing its job. (Incidentally,
as I mentioned earlier, I swaged the dent out. Since then, I've had
no ejection problems.) From what I'd gathered, I'd thought that dry
firing wasn't the purpose of that pin. Now that I know, it's a
simple enough task to reduce the length of the firing pin slightly
while maintaining its tip's angles and linear dimensions. I don't
know that the firing pin is actually proud of the breechblock
when I push it forward; it may be that there's a slight amount of
spring to the crosspin when it gets hit sideways and that's what
allows the firing pin to touch the breech face lightly. I will
investigate.
Thanks to several for explaining the hammer's a MIM part. Ended
my confusion as to whether it's sintered or injection molded -
it's both. Is a MIM part as good as the normal S&W part which
seems to be cyanide case-hardened mild steel? I'm thinking the
normal part should have better shock resistance, something even an
enclosed hammer should have, in my opinion. I received the new
hammer in the mail yesterday, will get a chance to try it out shortly.
Am tempted to order a normal hammer from Numrich if they have one.
Thanks again,
John B
PS: Have you looked at the prices on S&W's parts list? They used
to be so inexpensive. I don't know what happened; got no shame?
PPS: The thing runs fine with the magazine disconnect spring out -
no problema. I left the magazine disconnect itself in place to
keep the trigger bar/disconnector in place.
Bill VH
Bercovitz) writes:
#
#Bill Van Houten (USA Ret) and Stan Schaefer both write that the
#breechblock retaining pin (06509 bolt pin in S&W parlance) is
#supposed to keep the firing pin from contacting the breech face.
#Actually, the guy at S&W who took my order for the new hammer
#told me the reason dry firing was proscribed is that _some_
#firing pins will hit the breech face. That also explains why the
#dent in the breech face of my M41 was so light that it was hard
#to see: the retaining pin was _almost_ doing its job. (Incidentally,
#as I mentioned earlier, I swaged the dent out. Since then, I've had
#no ejection problems.)
My retarded Brother (sorry Bro) is enamered of a M2 Ruger. He even
tried changing barrels with a Ruger 45/22 once. It worked but he didn't
like the change of balance.-------- Anyhow --------- While cleaning the
thing once he forgot to replace the cross pin that does the same thing
as in the S&W 41. Result-- peened chamber face, eratic extraction.
Miraculously he found the pin and replaced it, cleaned up his chamber,
and has been dryfiring happily away since then.
Bill Van Houten (USA Ret)
Thermopylae had it's messenger of defeat, COME AND GET THEM !
The Alamo had none.
Stan Schaefer
#
# Thanks to several for explaining the hammer's a MIM part. Ended
# my confusion as to whether it's sintered or injection molded -
# it's both. Is a MIM part as good as the normal S&W part which
# seems to be cyanide case-hardened mild steel? I'm thinking the
# normal part should have better shock resistance, something even an
# enclosed hammer should have, in my opinion. I received the new
# hammer in the mail yesterday, will get a chance to try it out shortly.
# Am tempted to order a normal hammer from Numrich if they have one.
#
# Thanks again,
# John B
#
A 41 used to cost less than $200, too. That was in the days, though,
when $450 covered my college tuition, room and board for a quarter and
minimum wage was around $1.50. A lot has changed in manufacturing.
The way things used to be, they'd have a bunch of guys running a bunch
of machines getting paid per piece. So they'd have a lot of binned
parts laying around that really didn't have guns on order to match up
with. Anything over and above what they actually had to build was
spare. Now, with just-in-time and other management concepts, they
probably have to schedule production of spares. Cuts the overhead,
increases profits, cuts inventory taxes.
I've personally had no problems with the few pre-agreement Smiths I've
got that have MIM parts, the rebound slides don't take as good a
polish as the old ones and there's no plated parts available to match
stainless frames. No functional problems, though. I can't tell the
difference between my old ones and new ones as far as trigger pulls
are concerned, they're all crisp, smooth and clean. I've read that
some smiths like the new parts because they're square and uniform, not
many tool marks. Some of the Lear-Siegler guns were awful that way.
Probably, if they'd stuck with traditional forged and machined parts,
you'd be paying twice as much for the same gun.
Stan
John Bercovitz
# While cleaning the thing once he forgot to replace the cross pin
# that does the same thing as in the S&W 41. Result-- peened chamber
# face, eratic extraction.
At least your brother omitted the cross pin accidentally! Thirty
some years ago I did the same thing, but just to see what would
happen. That's when I learned how to make a chamber swage out of
tool steel.
Stan Schaefer writes:
# That was in the days, though, when $450 covered my college tuition,
# room and board for a quarter and minimum wage was around $1.50.
That statement establishes that we went to college at approximately
the same time, and I know when that was, oldtimer. ;-)
# I've personally had no problems with the few pre-agreement Smiths
# I've got that have MIM parts, ...
Well, maybe I just ran into probability, then. Perhaps I should save
my money and not buy spare M41 parts from Numrich.
Along the lines of cost cutting - when I replaced the hammer, the
interior of the pistol reminded me of some other firearms, but it took
me a while to realize which. It reminds me of Russian and Chinese
firearms - extremely rough machining where it doesn't matter. The
difference is that the S&W finish is superb where it does matter. Oh,
I'm not talking a custom gun finish, but it's really outstanding for a
production gun. Flat surfaces, no rolled edges, good bluing. Almost
hate to shoot the darned thing. And the trigger pull is indeed very
good; I spent about 40 hours bringing my old Ruger up to (and past) the
level which you can buy off the shelf from S&W. Corrected its mating
surfaces, replaced the pins with oversize pins and opened up the pin
holes for .0003" diametral fit with the pins.
John B
PS: I carefully checked the firing pin protrusion and it does not
protrude past the face of the breech block normally. So this is a
dynamic problem - it protrudes if whacked hard enough, evidenced by
the very slight dent in the breech face. I won't have to whittle
much to correct the problem.
John B
# [....]
# New S&W parts are made via MIM, sort of a squirt and
# bake approach to making complex parts cheaply. Might be you've got
# an example that was over-baked.
# [....]
An update on the replacement S&W MIM hammer I put in the pistol. It
has not lost half its sear notch to breakage as the previous one did,
but it's getting a dent in it where it hits the firing pin.
So we have brittleness combined with softness. Great.
John Bercovitz
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Joel Jacobs
# has not lost half its sear notch to breakage as the previous one did,
# but it's getting a dent in it where it hits the firing pin.
Does this mean you are dry firing the pistol?
John Bercovitz
# # An update on the replacement S&W MIM hammer I put in the pistol.
# # It has not lost half its sear notch to breakage as the previous
# # one did, but it's getting a dent in it where it hits the firing
# # pin.
# Does this mean you are dry firing the pistol?
No, can't do that as the firing pin will put a deeper dent in the
barrel.
You'll laugh, but I don't like to leave it cocked so I pop the barrel
off and remove the slide and lower the hammer when I store it.
John B
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