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Discussion Starter · #1 ·
Hello folks,

How common is slam fire with Garands?

I had an apparent slam fire incident with a Garand last weekend.

I was single loading HXP for standing practice. After about 30 rounds or so, the rifle went off upon bolt closing. The muzzle was pointing in a safe direction.

I later took the rifle apart. It was relatively clean. There was some light oil in the bolt, but the pin was moving freely and easily. It is the lighter style pin.

I picked up the hot case. It has a different looking pin strike compared to the rest.

I also shoot reloads with this - WLR primers.

Any suggestions?

Daniel39
 

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Keep the rifle pointed in a safe direction at all times!
Use the hard mil-spec primers if you reload.
I'm surprised it happened with HXP ammo.

Did you bump the op-rod to get it to go forward? I am suspecting so, as it gives it harder action forward, than if you've
jammed in a clip with your thumb and palm pad on the op rod. I saw a slam fire when it happened when the guys palm was on top of the bolt
and it was ugly. Split the guys palm wide open, 5" long, and deep, and burned in gunpowder.
I got real respect for a M-1 slam fire right there.

You checked the bolt and firing pin. Did I read somewhere (or was it on AR's) that some firing pins have a milled shoulder on them that sometimes
hangs up inside? I think it was the M-1. Perhaps someone else has more info.

Glad no one was hurt!
 

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I find it hard to beleive this happened with surplus HXP. You need to completly dissasemble the bolt and thoughly clean it inside, install pin dry or if you want to oil put a drop on your fingers and rub over the pin.
 

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I suggest you also take a look at the notched (for lack of a better term) 'bar' that runs across the receiver at the rear of the bolt (the thing that makes the bolt a bit 'fun' to get into the receiver) and the opposing front surface on the 'tail' of the firing pin.

With the rifle disassembled, slowly rotate the bolt closed and check to see if the forward movement of the firing pin is blocked by the bar across the receiver right up until the bolt is in battery.

Those two components are intended to interfere with each other until the bolt goes completely into battery, keeping the firing pin from being able to reach the primer. If either (or both) part(s) is(are) enough out-of-spec, the desired interference may not be there.



I don't believe the problem is likely caused by a stuck firing pin because the 'bar' should forcibly retract the firing pin before the bolt closes.
 

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Slam fires are not uncommon with Garands. Military rifles have free floating firing pins that move inside the bolt. When the bolt stops it's forward movement, the firing pin lags behind just slightly and continues forward striking the firing pin when the bolt comes to a stop. Slam fires are most common when single loading. The action of the bolt stripping a round out of the clip is enough to slow things down and keep the firing pin moving with the bolt. Don't dismiss a high primer in the ammo, but this isn't too often seen in MILSURP ammo.
A series of events is usually the cause, not just one mechanical fault or glitch. Most slam fires occur when the round is seated nearly all of the way into the chamber and the bolt has nothing to slow it down as it moves forward over the bullet guide. Easiest way to avoid a slam fire is to make sure the round is only about a third of the way into the chamber and to hold onto the oprod and let it go after the bolt face is about half way over the bullet guide. There is no guarantee that you will never get another, but these are the easiest things to do to reduce the possibility of them occurring in the future regardless of the source of the ammo.
Good luck in the future
 

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Discussion Starter · #6 ·
Thanks for the suggestions.

I took the bolt apart. It looked fine. No dirt inside, no burrs, no sharp edges in any of the pieces. Cleaned with a small brush, wd-40 and compressed air. Re-assembled dry.

Please note that this incident did not take place out-of-battery. The bolt was locked - at least enough to secure the action.

Attached are a few pictures of the HXP brass. Note the different pin mark on the slam fire case.

What do you make of these pics?

The black coloring on the head may have been there before firing as some of this is dirty, not sure. There was no evidence of gases escaping out of the action.

Daniel39

 

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The strike on the slam fire case was a light strike that was just hard enough to set off the round so it's not going to look like the others.
Slam fires are not an out of battery occurrence. The pin strikes the primer just as the bolt locks into battery.
 

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First thing is Don't use WD 40 inside anything. It is not a lube it's a water displacement mix. With time it can build up inside things and becomes a magnet for dust, dirt and powder residue. That can then harden and can be very hard to remove. You can use WD 40 on the outside of the bolt or anywhere else but not on internals.

Next is the round that fired has the look of being over loaded and having higher then normal pressure to it resulting in a cratered primer. But it can also have been a sensitive primer that went off with just a bit of a hit from the firing pin when chambered. That can also produce a cratered primer.
 

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+1 on the WD40,

lube the M1 with grease, and if you put a tad bit (drop as mentioned) of CLP or similar to lube the firing pin

save the WD40 for a squeaky door hinge or anything else
 

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WD40 should be banned from any place where firearms are located! It is great for removing glue from store labels and quieting the squeaky door hinge but NOT lubricating firearms. A good analogy would be like using Johnson's Baby Oil to your cars crankcase. WD40 and firearms are not good for each other.
 

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I have had an out of battery discharge or "slam fire" with my M1 Garand rifle using HXP Greek surplus M2 .30-06 ball ammo. I was prone, slow-fire, loading cartridges directly into the chamber and then "easing" the bolt forward to a point I assumed [never "assume" yes?] was OK, and then having it run forward under the op-rod spring's pressure. Every now and then a heel of the hand rap was required on the op rod.

Well, it could be the following things:
1) The firing pin could be out of spec. If the firing pin gets elongated, it could basically fly forward when the bolt turns into locking engagement with the receiver with sufficient force to strike the primer. This is often attributed to firearms like the French 49/56 firing pin, and softer commercial primers, but it is not unknown.
2) There was a foreign body or some kind of material adhering to the face of the bolt, possibly even a primer from a previously fired cartridge, or some kind of piece of the case or grit, gravel, etc. that struck the primer with sufficient force when the bolt closed on the chambered cartridge.

Good luck figuring out what happened! It is disconcerting. A fellow M1 enthusiast gifted me one of those single-shot clip adapters because he did not care for me loading on the line with a cartridge directly in the chamber. Certainly the Garand manual says that's how a single-shot should be loaded, but it is easy enough to temporarily install the single-shot adapter in lieu of a clip into the magazine, twist the cartridge under the feed lips, and then load the single cartridge that way.
 

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Discussion Starter · #12 ·
Slam fires are not uncommon with Garands. Military rifles have free floating firing pins that move inside the bolt. When the bolt stops it's forward movement, the firing pin lags behind just slightly and continues forward striking the firing pin when the bolt comes to a stop. Slam fires are most common when single loading. The action of the bolt stripping a round out of the clip is enough to slow things down and keep the firing pin moving with the bolt. Don't dismiss a high primer in the ammo, but this isn't too often seen in MILSURP ammo.
A series of events is usually the cause, not just one mechanical fault or glitch. Most slam fires occur when the round is seated nearly all of the way into the chamber and the bolt has nothing to slow it down as it moves forward over the bullet guide. Easiest way to avoid a slam fire is to make sure the round is only about a third of the way into the chamber and to hold onto the oprod and let it go after the bolt face is about half way over the bullet guide. There is no guarantee that you will never get another, but these are the easiest things to do to reduce the possibility of them occurring in the future regardless of the source of the ammo.
Good luck in the future
NavyChief, thanks, your advice makes a lot of sense to me. I was indeed loading the rounds by hand into the chamber. So was Dave Carlsson per his post. I will not do that again. Maybe use the sled. I'm pretty sure my rifle is perfectly fine.

I'm curious, your post has some pretty specific advice - have you done testing on your own or is this Navy collective wisdom?

I wonder if there is more to this than just the mechanics. Feeding the round into the chamber by hand allows it to heat up before the bolt is slammed close. I had shot over 30 rounds and the rifle was warm or hot even. I hand fed a new round after each shot, then waited a while before closing the bolt.

Perhaps the hot chamber heats up the case/primer and makes it more sensitive. The primer could go from 75F ambient to 150 or 200F in a minute or so in a hot chamber.

Daniel39
 

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I've did quite a bit of research and reading from various sources while developing a handload for the Garand. If you look enough for handloads, you'll start seeing a lot about slam fires.
 

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Many can be attributed to having a high primer when reloading. The primer MUST be below the rim of the case in the primer pocket. Even just a little bit above the rim can be enough for the slam fire to happen so take care in reloading for any semi-auto rifle that has no spring loaded firing pin.
 

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Is it me or does the primer look proud on the offending round?
 

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Slam fires are not uncommon with Garands.
Absolutely NOT SO !!!! In over 30 years of shooting the Garand rifle I have NEVER had even one slam-fire, nor have I witnessed any at the many matches I have competed in. I have used all makes of primers as well. The key to not getting a slam-fire is to be damn sure the primers are seated below the case head. At the very least, seated even with the case head. A "high" primer is a prime candidate for a slam-fire however.
+1 with the non-use of WD40. When the carrier (the liquid) evaporates, what is left behind is a coating that is akin to varnish, or shellac, neither of which you want in or around your firearms.
Jon
 
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