M1 carbine slam fire
Wayne
casing didn't fully eject and stopped forward motion of the bolt. Since the
next round was partially chambered, I eased the bolt backward just enough
for the casing to drop out.
Then when the slide was released, the gun slam fired. I have spent some
time trying to recreate the condition with no luck.
Yes, I was pointed quite safely downrange, and yes, the slide was activated
with the little finger. (Otherwise, I would have a different problem to
report!)
Any suggestions on why the slam fire?
--Wayne
[MODERATOR: What ammo? ]
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BP
What make was the carbine? More particularly, was it GI or a commercial
one? The GI had several safeties designed into it. The "hook" on the
firing pin, the hardness of the bolt and the shape of the hammer and the
opening in the bolt for it. Thus, assuming a proper length firing pin and
"bridge" in the receiver, the firing pin could only strike the ammo
(assuming the primer was properly seated) when in battery. Similarly, if
the bolt wasn't in battery the hammer couldn't "enter" the bolt bto strike
the firng pin. The commercial M1's sometimes omitted these features or
bypassed them. Ex. softer bolt steel the would deform with use and let the
bolt strike the firing pin when the bolt wasn't in battery.
Of course there is always teh chance, particularly if it was reloaded ammo,
that the primer wasn't properly seated. If it projected out of the
cartridge some you could have the slam fire even in a properly maintained
GI M1.
Walter Martindale
> ...
As the moderator asked - what ammo?
The firing pin is free-floating and if your primers are a "soft"
brand, the firing pin can continue forward with enough momentum to
fire some occasional primers.
Or if it's handloads, was the primer properly seated?
As a check, close the breech (little finger and salute, of course)
normally - if it doesn't slam fire, eject the round and examine the
primer - has it been dented? How much? Some primers are a little
harder and better suited to M1 - however I'm not familiar enough with
which is which to recommend one brand or another. (even in loaded
factory ammo - same thing - some primers need a little more whack than
others...
W
R.M.R
some
time trying to recreate the condition with no luck.
~~~~~
Well they do have floating firing pins, and soft primers could be the
culprit, but of the three M1 Carbines I own, two vintage and one
reproduction, I never noticed a dimple on the primer after ejecting a
live round like that of an AR. Could be your firing pin hole is
wearing out and enlarging, combined with need of a good cleaning. I'll
run a few rounds through one of mine tomorrow just to be sure but as I
stated, don't believe mine in particular leave a dimple on the primer,
maybe others do...
Ray,
(Si vis pacem
para bellum)
Argent
> ...
Was this a WWII carbine or a commercial carbine? Some commercial
carbines can fire slightly out of battery.
Wayne
Thanks for all the good info guys! I'll try to address all the responses
here.
The carbine is an Underwood. I have done no mechanical work on it other
than a thorough cleaning before first firing it, and a good cleaning after
every outing.
The ammo is Sellier and Bellot.
The slam fire was with a slide drop of about 3/4 inch.
The hammer can be trigger released with the slide partially opened, but this
appears to be a design "feature", as the manual (TB 23-7-1) suggests
dropping the hammer on an empty chamber with the bolt slightly opened.
Thus, I may have dropped the hammer before noticing the jam....but maybe
not.
Still playing with it.
--Wayne
sta...@prolynx.com
firing pin should be working. With the gun stripped, you should be
able to retract the bolt just a bit and the firing pin should be
positively withdrawn from the bolt. You should be able to see this
when looking at the bottom of the receiver. The firing pin tang
should hit the receiver "shelf" under there and get withdrawn. On
closing, the "shelf" should block the forward motion of the firing pin
until the bolt rotates into locked position. If this DOESN'T happen,
the firing pin or the receiver is worn and a slam fire can occur.
Usually the firing pin tang is worn, but tolerances on the things are
such that miscellaneous parts just thrown together can cause problems,
one reason that this is depot-level check after rebuilding. M1 Garand
and M14/M1A are similarly designed. Something to check for when
getting used examples of any of them. Firing pin protrusion should be
checked, too.
Stan
Wayne
Thanks! I won't be out to the range until next week, and this gives me
something to check out without ammo.
--Wayne
haraoi_conal
# With a genuine G.I. carbine, the interlock between receiver, bolt and
# firing pin should be working. With the gun stripped, you should be
# able to retract the bolt just a bit and the firing pin should be
# positively withdrawn from the bolt. You should be able to see this
# when looking at the bottom of the receiver. �The firing pin tang
# should hit the receiver "shelf" under there and get withdrawn. On
# closing, the "shelf" should block the forward motion of the firing pin
# until the bolt rotates into locked position. �If this DOESN'T happen,
# the firing pin or the receiver is worn and a slam fire can occur.
# Usually the firing pin tang is worn, but tolerances on the things are
# such that miscellaneous parts just thrown together can cause problems,
# one reason that this is depot-level check after rebuilding. �M1 Garand
# and M14/M1A are similarly designed. �Something to check for when
# getting used examples of any of them. �Firing pin protrusion should be
# checked, too.
#
I didn't see my other post yet. Forgive me if this ends up being
reposted.
http://www.m1carbinesinc.com/safety.html
has a really nice photo set showing the above safety check.
Wayne
# I didn't see my other post yet. Forgive me if this ends up being
#
# http://www.m1carbinesinc.com/safety.html
# has a really nice photo set showing the above safety check.
#
Thanks!!!
--Wayne
R.M.R
however I've seen several slamfires hit the fan on what appeared to be
squeaky clean guns. With floating firing pins it's the dirt you can't
conventionally clean or see, the crud inside the bolt where the
heartbeat is. This is especially true with AK's. You'll see all kinds
of matter throughout the inners of a new gun, and even a car power
washer (which I use to clean them) won't detach the mystery dirt in
the bolt. Ya gotta' get your digits in there and you'll be amazed what
comes out, if not your piece is still dirty even if it looks as clean
as grandma's fine China...
Ray,
(Si vis pacem
para bellum)
sta...@prolynx.com
# Some folks believe their weapon is clean, and that can very well be,
# however I've seen several slamfires hit the fan on what appeared to be
# squeaky clean guns. With floating firing pins it's the dirt you can't
# conventionally clean or see, the crud inside the bolt where the
# heartbeat is. This is especially true with AK's. You'll see all kinds
# of matter throughout the inners of a new gun, and even a car power
# washer (which I use to clean them) won't detach the mystery dirt in
# the bolt. Ya gotta' get your digits in there and you'll be amazed what
# comes out, if not your piece is still dirty even if it looks as clean
# as grandma's fine China...
#
# Ray,
#
# (Si vis pacem
# para bellum)
#
Had an SKS that had cosmoline that had frozen the firing pin forward,
would have slam-fired if I hadn't stripped it. Bolt is much easier to
strip and reassemble than an M1 carbine's, though. Also, no interlock
between bolt, receiver and firing pin like the M1, M14 and M1 carbine
all have. Still firing pin tips can break off and stick, a bolt tool
is cheap insurance, a spare fining pin, ditto.
Stan