View Full Version : M1 Garand blow ups

April 7, 2009, 05:33 PM
Anyone ever had an M1 Garand blow up on you or ever seen it happen to someone else?
If so, what was determined to be the cause?

April 7, 2009, 05:39 PM
I'vd seen a few, all were traced to the case not being propertly resized. (Too long between the shoulder and rim). Not allowing the bolt to lock up, then went off do to slam fires.

Now I carry a case gage (in 223, 308, & 06) when I'm running the line. If the suspected reloads dont fit the gages, the gun is pulled off the line until more ammo is found.

April 7, 2009, 07:19 PM
Never actually saw one blow, but I've examined a few.

The "usual" reasons for a blown M1 are:

Over loaded ammo.
Someone just screws up and puts the wrong powder or too much powder in a case.
One I saw was one where the reloader just plain screwed up and dropped a charge of Bullseye pistol powder instead of IMR powder.

Slam fire.
This is where the rifle fires when the bolt closes, and before it's locked.
The most common reason for this is reloaded ammo in which the primer wasn't seated all the way.
The second cause of slam fire is a defective or worn rifle.

Blown M1's are not common, and in virtually every case it's because the owner screwed up in some way. Either with reloaded ammo, or by shooting a defective rifle.

April 7, 2009, 07:29 PM
Another cause (I believe) is improperly resized brass in reloaded ammo. This can stop the bolt before the receiver bridge catches the tail of the firing pin during normal bolt lock-up. Even if the primer is properly seated, the free-floating firing pin could impact it hard enough to set it off, if the brass stops before it chambers.

This may be more important if you have a reproduction Garand, especially one with a tight "match" chamber.

April 7, 2009, 08:08 PM
I had two out of battery slamfires in Garands, both with Federal primers. I had one in battery slamfire with Federal primers. One of the out of battery slamfires blew off the back of the receiver.

Since then I became very interested in the root cause of slamfires in these rifles.

I found that "common knowledge" was full of myth, legend, and misinformation.

The Garand/M1a has a free floating firing pin. You can verify that the firing pin is hitting the primer by just chambering a round. There will be a dimple on the primer.

The original round firing pin used in the Garand is a collector's item. I have never seen one, but I read that Orion 7 had them at $100.00 apiece. They sold out before I could get one. The Army lightened the Garand firing pin, and it must be obvious why: slamfires. They must have experienced slamfires with GI ammo and the heavier firing pin.

Ignoring mechanical malfunctions and debris on the bolt face, the primary cause of slamfires is overly sensitive primers. If that free floating firing pin hits a sensitive primer with sufficient energy, the primer will ignite. It is important to use the least sensitive primers you can find in these rifles.

Aggravating factors are overly long cases. In the pictures below, the bolt is at the location where the receiver bridge is starting to block the forward movement of the firing pin. These are two different Garand actions in very good condition. You can imagine, that if you have an overly long case, and a sensitive primer, just at this point the bolt is stopping and sizing the case to the chamber. While the bolt stops, the firing pin is free to go forward and hit the primer. If the primer is at the low end of the ignition threshold, the rifle will have an out of battery slamfire.



Avoiding slamfires is a process. The first step of which is full length resizing of cases, setting up the dies with a case gage, preferably using small base dies. The next is to use the least sensitive primers you can find, and seat them below the case head.

You never want a long case, a “fat case” or a primer above the case head. And you want to use the least sensitive primers you can find.

Below are other folks experiences with Garands and slamfires.


“While the M1 and M14/M1A do have the "web", slam fires are still possible and can be catastrophic. I was lucky enough to come through one with a GI Springfield M1 from the DCM about 20 years ago using LC 69 issue ammo. The rifle held together for the most part, but did fire out of battery on loading a single round in slow fire. If it had been in a rapid fire string, I most likely would not be typing this right now. The rear of the receiver from just aft of the serial number was blown off and the stock cracked with a big chunk blown out of it. The bolt was jammed into the back of the receiver and would not come forward. The op rod handle ripped the palm of my hand open, and you could read the head stamp of the case in reverse on my palm. The recovered empty case was about an inch long. Never did find the rear of the receiver. The DCM took the rifle back and never did tell me what they determined went wrong. They replaced it with a brand new, and I mean, brand new, never issued H&R.

If you shoot either the M1 or M14, I would highly suggest you either use a SLED with the M1 or load single rounds from the mag on the M1A. Reloads should use the harder primers, like CCI, and I check mine with a seating gage. ”


“In the summer of 1968 or 69 the Atlantic Fleet Rifle Matches were plagued with slamfires using .308 Match ammo. Seems a terrible long time ago, and I still get upset about it because I lost my best and only chance to leg out on that cartridge. I was in the first relay at 500 yards (not 600 because the Annapolis range only went out to 500), and someone else popped off the first slamfire and dumped a bullet into Chesapeake Bay. I think I was the second or third to do so, and dropped my score from winner to first leather. The range officer did not allow a refire for any of us in first relay. By the second relay, the ammo malfunction was quite evident, and refires were given, but nothing was done for those of us in first relay. Slamfires popped all afternoon, was not a pretty sight. On examination, and believe me everyone was looking at ammo that day, the decision was a batch of overly sensitive primers. I guarantee, a slamfire can run your entire day!!!”

I have read at least two accounts of Garand shooters having slamfires using Federal American Eagle ammunition. One was at a Garand Match in CA (I think). The shooter had loaded a round standing, dropped the bolt, and the rifle discharged into the ground.


dmftoy1 Senior Member Join Date: 11-17-03Location: Lexington, ILPosts: 1,947 FWIW if you're going to use commercial ammo (non-nato) I would not single load if you decide to do any service rifle matches as the softer primers (IMHO) are a greater risk of a slam fire. I was recently shooting next to a guy shooting Federal American Eagle 150 grain (30-06) in a Garand and he had a slam fire upon releasing the bolt. I think if you're loading from a magazine you're probably ok as the extra "drag" slows down the bolt slightly. Just my .02Regards,Dave

2008 slamfire with Greek HXP 88 30-06 ammunition.

Re: M1 Garand / Hang fire ?
Levisdad <Send E-Mail> -- Tues 3 Jun 2008 8:54 am
Yep 1988, Lot hxp 88j001-002
I also had a slamfire out of this same lot a short time ago.
The slamfire was from closing the bolt using a two round clip. It was the second stage of rapid prone. I've fired 200 rds after that with out a problem. Until the two hangfires.


01-07-2009, 04:55 PM
SGT D USMC FNG Join Date: Dec 2008Location: oregonPosts: 13

I had a slam fire in a M1. feel free to disreguard this post because few shooters have first hand knowledge, and even fewer have had one. It only happens to others so why worry, except if you are using federal match (very accrate) primers in a gas gun, You are playing russian roulette. My slam fire was in the mid 1980's. It was with a Federal match primer. I got very involved in this and found 17 cases of M1 slam fires with one common factor, ALL WERE WITH FEDERAL MATCH PRIMERS.


January 21st, 2006, 05:17 PM
My right hand got tore up pretty good when my DCM Garand went hand grenade. I'm just glad it happened when I was single loading it, we never found the rear of the receiver, which I have a feeling would have ended up in my head. The worst part of the whole thing was, it happened in New Jersey and trying to convince the people at the hospital that it wasnt a "gun shot" wound and no need to bring the police into it.

January 21st, 2006, 09:03 PM
I believe it slam fired. The recovered case was missing the front half, which leads me to believe it fired out of battery. The ammo was DCM issued GI Lake City 69 and not commercial 30-06 or reloads. I sent it back to Anniston and they never did tell me what they thought the cause was. They did send me a brand new H&R though. I still shoot M1's, but I no longer load single rounds by allowing the bolt to go home on its own, and anymore, I usually use a SLED. I also only use CCI primers when I do reload, for both my M1 and M1A's, and I also mike the primers.

edit to add: I dont believe that the M1 and M1A's firing pins can protrude or reach the primer, due to a slotted bridge in the receiver, that wont allow the tail of the firing pin by until the bolt is closing or closed.

April 7, 2009, 08:36 PM
Slam fire, when you say case gage, are you talking about a case trimming gage?
And what are "small based dies"?
I've been looking at the Lee 3006 reloading dies.

April 7, 2009, 08:56 PM
No Sir:

When I talk about Case Gage here, I'm talking about the Wilson, Dillon, etc case gage that measures the case from shoulder to base. Used to set up your sizing die to make sure it sizes the case to specs.

What happens when a gas guns goes off, the gas pushes the bullet down the barrel, when the gas hits the gas port, or hole, it excapes pushing the operating rod back, starting the process of ejecting the empty case. The op rod/gas pistol, or straight gas blow back (depending on rifle) starts the bolt's extractor pulling on the rim WHILE the gas is still pushing on the inside of the shoulder, thus stretching the case, which needs to be brought back to specs during resizing.

If not, the case, from shoulder to rim, is too long, causing: FTF, FTE and in worse cases slam fires.

Two wilson gages are shown in this photo, the 223 & 308, the '06 is one I made. Notice on the wilson gage there is a slot on the top of the gage, Any case sticking out beyond the base is too long in head space, any case that sticks below the grove indicates short head cases. Also the gage lenth tells you if the case needs trimed.

RCBS makes a digital gage, its pricy but tells you how much out of specs. With the Wilson/Dillon you need a caliper to tell you how much.

They are simple to use, simple stick the fired case into the gage, determine if its flush, if not, adjust your sizing die until it is. Don't think SB dios will solve the problem, they size the diameter, you still have to adjust for lenght.

Most range officers I know, carry such gages to check suspected reloaded ammo and will have it removed from the line for safety reasons.

They are about 20 bucks, cheap insurance, or if you have a lathe, chamber reamer and old barrel you can make them yourself.


April 7, 2009, 09:32 PM
I use a Wilson type case gage. The Wilson is cut “fat” between the shoulder and the head, it measures length only. This does allow you to drop a fired case into the gage.

For gas guns, I size to gage minimum.


Before I got case gages, I followed the usual advice supplied with dies, which was to adjust the sizing die to the shell holder and add a quarter turn. After I got gages and was able to measure what was going on, I found this advice to be totally bogus.

A small base die sizes the case closer to factory dimensions than a standard die. RCBS told me that their small base dies size the case head .002” more than their standard die.

You can also over size cases with a SBD, unless you use a case gage to set up the die.

Folks have expressed sizing problems with SBD’s. The typical problems they express are extremely hard sizing, or stuck cases. This is because they are using a spray on lube, or some other inadequate lubricant. I use RCBS water soluble lube (because I wash my cases after sizing in soapy water) or Imperial sizing wax. These are very slippery lubricants. They do not make Small Base sizing effortless, but they really do reduce the effort.

Still, if you have a ballooned chambered rifle, squeezing the case back down is going to be a lot of work!

Just this week I purchased a 308 small base X-Die from RCBS. I don’t know if they make one in 30-06. I hope to have the small base sizing I want, and no trimming!

I have Redding, RCBS small base dies. You can buy them individually or with a seating die.


Life is a risk, reloading is a risk, but once you understand what to do for these rifles, shooting them is very low risk. I shoot mine regularly, just this weekend shot some reloads over the chronograph to determine velocities. The last I shot my match Garand in a Highpower match was Mar 09. It was a 100 yard reduced match. Posted are my two best targets. The other two targets: let's not talk about them. :barf: Since this thread is about Garand blowups, I will not go into powder selections and recommended velocities.



April 7, 2009, 10:46 PM
Kuhnhausen's book on the M1 / M14 &M1A series of rifles.

The explanation of the "Slam fire" is excellent.

there are two area of concern to deal with:
1: improper ammo, including "High" primer, where the primer are seat, with the impact surface above the face of the case head.
Here here best course is to swage the primer pocket to correct dimension and also remove remeants of teh crimp if using MIL_SPEC brass.

Small based dies rework the bras to minimum size as almost being a new case, but it cost you is fewer reloads. BUT if you are loading between two different rifle. then you may want to consider the SB dies.

I have used both commercial resizer and competition dies, the way I set the die, is to strip the bolt, then size a case long, place in chamber and attempt to close the bolt, if not closing then 1/8th turn the die down, resize until the bolt closes with no axial motion, one more 1/8th turn to just give me some perceive axial play.
This give max reloads per case. I've had no problems since doing HP in 1983.

Second, due to wear the rifel maybe at fault. Look at the M1 rifle stripped of teh bolt. under the rear edge of the reciever, is across-bar, with an "radial" slot about the 7 -8 o'clock position. The purpose is it allow the lower firing pin tang to slide along the inside face as the bolt rotates to closed position, this prevents the Fp from impacting the primer while the bolt is unsupported. The FP tang maybe worn or the slot has widen. ALso the nose of the hammer,
strikes the bolt forcing it closed before the FP is hit, this maybe worn.
Locate a gunsmith that was service trained, he can check out your M1.