Just curious; how many of you Garand shooters have had a slam fire?

The reason I ask is that I'm having them and would like to figure out why. The details:

1. I've never had a slam fire with CMP ammo.

2. My cases are Winchester full length resized.

3. My loads have all been conservative using Garand specific data from the Hornady manual.

4. Yea, I know about CCI #34 primers and I had my first and other slam fires using them. I thought I might have an excessively sensitive lot of primers so then tried WLR primers as called for in the Hornady manual and the problem persists.

4. The primers are adequately seated being below the cartridge head.

5. I've loaded for quite a number of different semiautos including an M1A in which I always used Federal 210M primers and have never had a slam fire except in the Garand.

I await for whatever wisdom you can supply.

Of the numerous "slam fires" in M1 Garands I have investigated over the years all have been due to faulty "trigger jobs". The result was actually a "double" or the hammer falling when a round was chambered, not a "slam fire".
I also am discounting the several times where the operator had his finger on the trigger and inadvertently pulled it when the action slammed forward. That is the major reason for ADs with M1911s BTW.

Larry Gibson

I'm pretty sure I'm having slam fires. I pull the trigger and 2 rounds, and never more than 2, go off in very fast succession long before I can release the trigger. The entire gun was overhauled by Miltech to supposedly new condition probably not much more than 200 rounds ago.

It's also interesting that of the probably 100 rounds of CMP ammo I've put through it, I've never had a slam fire.

quote:

Originally posted by Grumulkin:
I'm pretty sure I'm having slam fires. I pull the trigger and 2 rounds, and never more than 2, go off in very fast succession long before I can release the trigger. The entire gun was overhauled by Miltech to supposedly new condition probably not much more than 200 rounds ago.

It's also interesting that of the probably 100 rounds of CMP ammo I've put through it, I've never had a slam fire.

So, assuming it is a slam fire then what ammo does it happen with?

Larry Gibson

It has only happened with handloads. As noted above, they're not even at the maximum load listed in the Hornady manual for the Garand and it has happened with both CCI #34 and with WLR primers.

I have not yet tried commercially loaded ammo other than CMP ammo though I do have a box of Winchester factory loaded cartridges loaded with 150 gr. bullets I'm going to try.

I was using a friends grand for a match one time. Had a real nice trigger. During parctice a whole clip went down range with one pull of the trigger.

So much for his trigger job.

I never had a slam fire. but I have had a couple "doubles". Both were due to my not holding the trigger back through recoil. Embarrassing and not conducive to scoring well either.
Only other thing I can think of is a primer that is not seated below flush.

muck

Check to see if the action is loose in the stock,things are not always as tight as they might seem.
Use your thumbs to push forward on the back of the reciever and then use the barrel group to push back if it's loose and you will see and feel it. Mine doulded and glass bedding cured the problem

I've made very sure all the primers are seated below flush.

I'm quite sure I'm not doubling by pulling the trigger and if I were, it would also happen with CMP ammo. I've run multiple 8 round clips of CMP through the gun with nary a slam fire while one slam fire per clip is the norm with my reloads.

The action is not loose in the stock.

Just a suggestion, but do you have method/tools to determine your chamber diminsions base to shoulder/datum line? Reason I mention is that you state that only your reloads are giving you the problem. Even though your primer depth is OK I would double check if there is significant difference between the unfired CMP ammo vs your reloads as mentioned. In any case, would not fire rifle with this occuring for all sorts of unwanted occurences will take place. Again, just a suggestion.

I made some case measurements using a dial indicator which obviously isn't the most precise way to measure. Also, measuring head to angles is a little subjective as it's sometimes difficult to see exactly where the angle starts. That being said case measurements are as follows (average of 5 cases):

Head to body/shoulder angle:

CMP - 1.964
Fired reloads with Winchester cases - 1.983
Full length sized Winchester cases - 1.985
Factory Winchester cartridges - 1.980

Head to neck/shoulder angle:

CMP - 2.134
Fired reloads with Winchester cases - 2.129
Full length sized Winchester cases - 2.129
Factory Winchester cartridges - 2.133

A bottle necked cartridge could headspace on the body/shoulder area and or the neck/shoulder area. I would say when that is taken into consideration, there isn't much difference in cartridge dimensions.

By the way, I appreciate all the suggestions.

Just a thought, does it fire the second shot every time, if not unload second round and look at primer. Also try loading one of your reloads on top followed with CMP round. Unload second round after first shot and inspect primer for light strike mark. Also try loading dummy round with no primer, put second in mag, load reload first, fire and see if the hammer has fallen after 1st shot.
C.G.B.

It fires twice after the trigger is pulled? That ain't likely a "slam fire" which is normally considered a discharge that is caused by a long/broken FP, a long cartridge/high primer and is often accompanied by a ruptured case (if firing is actually occurring before teh bolt locks (in an in-spec M1 or M1A, the FP cannot reach the primer until the bolt rotates closed and the FP tang clears the rear bridge)...

If the hammer falls twice, it is a double and likely a failure of your trigger/sear hooks.

Have you checked the front hooks for engagement depth? Should be about 30-50/1000 worth of contact between the sear and the front hooks. How light is trigger? Does it have a stock/issue length and strength spring?


Load a primed but not charged round as the second round (with bullet- don't worry, if it fires the bullet will probably not move..., then a standard round as the first shot, fire shot 1. If the hammer fell, then it is a trigger assembly issue and not a slam fire. If it fell the primer in round 2 should be fired and look normal- a proper looking FP indentation. If the hammer does not fall, and the primer is fired, check your FP for length/fracture and also examine the FP cam/rear bridge for damage etc. It should have a smooth angled surface on the left (the FP retraction cam, a flat edge at 6 oclock (the FP block). Both of these surfaces engage the Fp tang and either block it from forward movement until the bolt rotates the tang past the block, and over the angled surface, which then withdraws the FP rearward as the bolt rotates open, before the bolt starts its rearward movement.
If excessively worn or damaged, it could allow the FP to impact the primer as the bolt closes casuing a "slam fire" situation. Also check for grease/crud in the FP channel-it could cause issues as well-fp should be lubed with CLP or similar light oils, not grease.

Hope this helps....

A review of the facts:

1. Slam fires have never occured in over 100 rounds of CMP ammo. If it were a problem with the sear, etc., one would expect the problem to occur irrespective of the ammo used. Right?

2. The gun is pristine with no crud build up etc. If was redone to like new condition by Miltech probably less than 200 rounds ago. I presume it's possible that Miltech screwed something up though. If I can't find another reason for the problem, I'll contact them.

3. On the average, the double occurs once in an 8 round clip and has occurred randomly from beginning to end of the clip.

4. I've had no ruptured cases so I have to think the bolt has always been completely closed when the double occurred.

5. The second shot occurs so fast, it almost sounds like one shot. There is no time to release the trigger and accidentally fire the second shot and besides, if that were the cause, it would also have happened with CMP ammo.

6. As for the hammer falling a second time, that would seem unlikely as it should also have happened with CMP ammo of which I've fired much more than anything else.

So, the second case , fired w/o hammer falling, has no FP indentation?

I had two inbattery slamfires in Garands with Federal primers. I had two out of battery slamfires in Garands, with Federal primers. The second one blew the receiver heel into my face.

This was all prior to digital camera’s, what I would give to have pictures of the blown up rifles.

I have continued to shoot my Garands and shoot them regularly. However I learned several things and my reloading practices are much more particular than they used to be.

I recommend that you always full length resize, I recommend small base dies. Regardless of die type set up your die with a cartridge headspace gage and size to gage minimum.



As a safety measure, you want the cartridge case to be smaller than the chamber. Shorter and slimmer than the chamber. Fat or long cartridges really, really increase the risk of an out of battery slamfire as the bolt has to de accelerate to crunch fit the case to the chamber, and in that moment, the free floating firing pin wacks the primer.

You want to clean the primer pockets.

Prime your brass by hand, inspect each primer and verify they are not cocked and are below the case head. Frankfort Arsenal set their primer seating depth between zero and minus 0.005”. I would try to be a little lower than zero at the case head. More than .005” you might have misfires.

Always use the least sensitive primers you can find. Never use Federals as they are the most slamfiring primer on the market. I don’t recommend Winchesters, in 1999 they redesigned their primers to be more sensitive. Slamfires are being reports with the brass finish Winchesters. I recommend CCI #34 and Tula7.62 as both are advertized as “mil spec”.

Trim your cases, charge your cases and never seat your bullet to the lands. Seat to 3.30” or less. Less is fine.

There are several categories of slamfires in Garands/M1a’s.

There are those caused by milking the trigger and upon recoil, the finger stays put but the trigger moves. Essentially these are bump fires. Seem to be happening more and more as more and more shooters shoot off benches. I never had one but I am a sling shooter.

There are those caused by mechanical defects. SKSs are know to have firing pins jammed forward and that will cause slamfires. Go here and see the video. http://www.murraysguns.com/sksown.htm When Garands/M1a’s “double” due to worn/trigger sear issues, they don’t get any better. Even though the hammer nose is supposed to rotate the bolt into battery before the hammer can hit the firing pin, I would not count on it indefinitely. Might get an out of battery slamfire at some point.

The receiver bridge is not a certain protector against slamfires or out of battery slamfires. The lower pictures show the slot on the receiver bridge and the location of the bolt lugs.






The firing pin was able to go through the bridge slot at the pencil line on the bolt lug. Even though lugs are engaged, they are not fully engaged.



This is the bottom of an M1 Carbine receiver, it is milled differently from the M1 Garand, but it is functionally similar:





The more I read your incidents the more I am worried about your safety. While I think it is possible you are bump firing, I am worried that your cases maybe overly long or overly fat. However lets start off with a list.

Is the firing pin clean and the bolt hole clean of gunk or residue that might stick the firing pin in a forward direction?

Do you have a case gage and did you check the OAL of your sized cases. Look at my gage picture, the difference in those ledges is the difference between GO and No Go. If your sizing die cannot push the shoulder back enough, you have a dangerous condition.

If you shoot again, use those CCI #34 primers and hold the rifle tight. You could be bump firing.

If your rifle continues slamfiring you have a real problem that cannot be diagnosed over a computer screen. Have someone expert look at it and your ammunition.

Well, the rifle is going back to Miltech for a thorough check. I had a long talk with a knowledgeble gentleman there today. According to him, it's possible that shooting off the bench could in part be responsible for the problem though that's likely not the only factor.

If you note the above case dimensions, those with my handloads are a little longer than CMP loads though they're quite similar to factory loads. I think it's possible that a small base die would help but I'm going to have the rifle checked out rather than go through more personal and perhaps hazardous experimentation.

I understand attempting to accurately measure the angles at shoulder and neck is "iffy" but let me suggest you take a pistol case, 9mm will work, and place over neck of cartridge, unfired vs fired and then place in caliper to determine actual measurement of base of cartridge to somewhere in the middle of the shoulder, Datum Line. I use a Davidson Comparator, small piece of steel machined to give same measurement as I described with the pistol case. As long as the pistol case falls somewhere on the slope of the shoulder it will give you a relative number in order to compare. The shoulder is the area for the headspace spec in the chamber. Again, just a suggestion. As mentioned earlier, the problem needs to be solved before any additional firings for the sake of your safety.

I would take a look at the bridge slot and the tail of the firing pin. If they are OK then this is what might be happening.

The trigger mechanism on a Garand if set too light or if parts are worn will some times double when the trigger is "carefully" pulled.

Usually airgun shooters and competitive pistol
are more likely to have this problem.

I have shot several Garands that I could make double at will, because of the way I controled the trigger.

The CMP ammo might just have a little more or less recoil thqan your reloads.

You reloads might have just the right amount of recoil to allow you to sometimes stutter step on the trigger causijng the rifle to double.

Worn sears and hammer hooks, or bad trigger jobs can add to the problem...

The rifle is back at Miltech being checked out at no charge. I had a long and informative talk with the head guy there and he said some of the same things you are saying.

Parts being worn shouldn't be a factor since it was restored to as new specs but who knows, maybe some dimension isn't quite right. I was carefully pulling the trigger but I don't think I was causing but doubling since it never happened with CMP ammo and the trigger isn't too light. The guy at Miltech said that shooting off the bench as I was could cause doubling.

Though my loads that doubled were conservative according to the Garand loads in the Hornady manual, I wouldn't be surprised if they are a little hotter than CMP loads.

Per my discussion with the guy at Miltech, I suspect the problem is not from a single thing but multifactorial. It's also apparent that the problem is not slam fires as I thought but doubling. The factor I think is the most likely major culprit is the fact that though the cartridges fit fine in the chamber, they weren't resized with a small base die.

I should have a small base die in a couple of days and should have my rifle back in a week or two for more shooting.

Are you getting the slam fires with a clip? When loading single rounds, if a Sled is not used, Garands are prone to slam fire.

After talking with the guy at Miltech, I don't think I'm getting slam fires but rather doubles and it has happened only with a clip. I don't use a Lead Sled.

It shouldn't be too long before I get the rifle back from Miltech.

Pay attention to what you are doing when reloading for a Garand/M1a. 1 June 2012 a poster reported an obvious out of battery slamfire he had with “grampa’s” ammunition. Grampa’s ammunition cracked the stock and the rear of the receiver. Who knows the exact ways Grampa’s ammunition was all dorked up. The lesson to be learned is you have to produce perfect ammunition for these actions because sloppy reloading techniques will cost you.

quote:

so about.. 2 and a half months ago a buddy and i were shooting the garand at the range. we were shooting reloads that my grampa and i made, he is an experienced reloader and has been doing this since the 60s. i have a 1942 manufacture spiringfield garand. anyway, about 5 rounds in, i pulled the trigger and heard 2 rounds go off. there was only 7 cases on the ground, for a short time we couldnt even find the missing case or any evidence of it. when we did find it, the neck was all ballooned out, and the case looked like a giant .45. so we are assuming what had happened was the round went off as it was being chambered, and we have no idea why. luckily the bullet left the barrel and i only got minor powder burns on my neck..
as a result of the incident, the rear of the receiver cracked on both sides, and the op rod was bent slighty and will not close the bolt all the way unless i give it a good whack. the stock was also cracked, and a nice chunk came out of the back of it.

http://thefiringline.com/forum...wthread.php?t=491559

Picture of the receiver heel.

Garands like medium buring powders. 4895-4320 Varget RL 15.

Use of unknown recipe "reloads" is not wise. most bolt gun 30/06 fodder uses slower (4381 etc) powders to maximize velocity and are too slow thusly over pressuring the standard desing of the gas system. I beleive the standard system is designed to operate with about 2400 PSI at teh port. Slower powcers often will exceed that by a large margin.

Factory ammo is the same- too slow burting, other than dedicated Garand Loads (Horn 168 AMAX is a a dedicated garand load).

If slower powders are desired, there are adjustable plugs available- Schuster and others.

I tried a Schuster, but could never get it to be as accurate as with a standard plus and powders- a 175 at 2675 and 4895 or 4320 is no slouch...

Of course, issue barrels and stocks not pressure bedded, upper HG not unitized/clearanced are not conducive to full cabpability of accuracy.

Excellent writeup and pictures, Slamfire. Especially like the picture of the receiver bridge and firing pin hook.

Lots of folks don't realize that, while effective in preventing slamfires on properly chamberedrounds, the bridge is of no use should a round stop short of being fully chambered or improper loads w/high primers.

The firing pin "pecks" the primer every time an M1 or M14 bolt slams home. If anyone doubts this, chamber a round, remove it and you will see an obviously dented primer. This is magnified should the bolt stop short on an oversized round, high primer, etc.

I have fired many thousands of rounds through gas guns using regular primers and have never had a slamfire in one of my rifles. Having said that, I now use CCI #34 mil spec primers when loading for the M1/M14 as an added precaution.

http://www.cci-ammunition.com/...s/primers.aspx?id=30

Thankfully, slamfires are a relatively rare occurrence in any gas gun, but they have been documented, especially in M1’s & M14’s. Do they occur in AR’s? I don’t know. Is it unreasonable to take precautions just in case……your call.

A slamfire in either the M1 or M14 can have disastrous results if it occurs before the bolt is in battery. The bolt design of the AR would seem to make firing out of battery nearly impossible since the firing pin is not long enough to reach the primer until bolt locks.

Lack of care in following careful reloading practices or a bit of debris on bolt face, or perhaps a broken firing pin, combined with a soft primer could cause a slamfire, even in an AR.

The following occurred with an M1, and illustrates what can happen should a rifle slamfire while not in battery. I have personal knowledge of several other such events that I did not actually witness. One was an M14 using military issue ammo in which the shooter received some serious injuries, so the hard primer is not absolute insurance against a slamfire.

A friend who is a very experienced highpower competitor and reloader wrecked his match grade M1 Garand using the same handloads he had used for years when the rifle slam fired out of battery. Bent his op-rod, blew extractor/ejector out of bolt and rounded the receiver locking lug recess about 1/8" showing the bolt lug (thankfully) had barely entered the recess but was not fully in battery at the time the slamfire occurred. He received a cut on the forehead and had somewhat of a problem with his trigger control for a while thereafter. Fortunately, the rifle, and his shooting ability have since been restored.

Upon examination of the remaining lot of ammo, we found that the rounds did not have sufficient headspace (clearance) in his snug, match chamber. He had loaded this batch of ammo using the same (full length) die setting as always. Remember, all previous lots had measured and functioned just fine. The problem stemmed from the fact that this particular lot of brass had been fired at least 8 times and had work hardened. His dies had been set to give proper headspace with once fired brass and he failed to check headspace on this lot after loading. The harder brass springs back more than softer brass after sizing which resulted in oversized (for his chamber)rounds.

Ammo is probably the number one cause of slam fires in the Garand & M14. Anything that can cause the round to "stop short" of full chambering can result in the firing pin hitting the primer with sufficient force to set it off. If this occurs before the bolt is in battery, it can be disastrous!

Soft primers can contribute to a slam fire. The CCI #34 & #41 military primers have a hard cup to duplicate GI ammo, most of which is loaded with a hard primer. Handloaders must be aware of two other factors that can result in slam fires.

First, make it a practice to run your thumb over the primer as each round is removed from the press to be sure that the primer is fully seated.

Secondly, each cartridge must be sized sufficiently to fit your rifle's chamber giving proper headspace clearance. I would not load for any "gas gun" without using a cartridge case headspace gauge as pictured in Slamfire's post above. Best practice is to run each case through the case gauge at the time the loaded round comes off the press after determining the actual headspace required for your rifle; remember, all rifle chambers are not created equally. At the very least, spot check every few rounds in a given lot of reloads (for this to be acceptable, one must keep all brass in lots that have been fired the same number of times).

Hopefully, this information may help someone else avoid this pitfall.

Regards,
hm

Great posts Slamfire and HM1996.
Excellent presentation of the nuances of reloading for the M1 and M14.
And what can happen if you don't pay attention to details and understand why.
Thanks guys.

muck

quote:

Do they occur in AR’s? I don’t know.

Yes, they do.

I had one loading my match AR15 in the standing stage. I dropped a round in the chamber and hit the bolt release. The rifle slamfired in battery taking a divout out of the ground in front of the line. Everyone saw it, some big eyed looks came my way. I full length resize my brass in a small base die and the WSR primers were seated by hand and I verified they were below the case head. My scorer, a State Champion, Pres 100’s patch wearer, laughed at me during the relay change and said something to the effect, “now I know how you got that knick-name” (Slamfire). The range gods were listening and during his standing stage, his AR15 slamfired in battery and took a divot out in front of the firing line!! He was using Federal match primers.

My WSR were the new brass WSR. In 1999 Winchester changed their primers from the nickel coated to brass, and they made these primers more sensitive. After eating up a handfull of firing pins with brass WSR, because they have thin cups, I don't use them.

I no longer hit the bolt release and let the bolt slam on a round in the chamber. In standing I lower the bolt half way and let it drop, then hit the forward assist. I always put on the safety, though it is a meaningless gesture, and I feed my rapid fire sitting shots from the magazine. Used to toss them in the chamber and hit the bolt release. My Bud, I asked him this year if he had any other slamfires in the AR15, and he had! One more with Federals, and that is the last he will use Federals in an AR15.

I was recently squadded with a member of the Army Reserve team and I noticed him putting on the safety each shot. Guess what, a shooter next to him at Camp Perry 2011, during the standing stage, his AR15 slamfired. So the Reserve shooter was doing the same meaningless putting the safety on, just in case, as I.

There are lots of reports coming out of slamfires in AR's.

It is my belief that any action with a free floating firing pin will slamfire given a sufficiently sensitive primer. Over time I have found slamfire reports on FAL's, AK47's, SKS's, MAS, M1 Carbines, M1a's, probably more but I can't think of them right now.

The primary difference between an AR action and a Garand/M1a/Mini 14/M1 Carbine is that the firing pin in a AR is only extended on cam down. In the other actions the firing pin is only retracted on cam down. You can have inbattery slamfires with AR’s, but with Garands/M1a’s/Mini 14’s/M1 Carbines, you can have inbattery and out of battery slamfires.
Guess which type of slamfire is the worst?

Hint: Out of battery.

quote:

One was an M14 using military issue ammo in which the shooter received some serious injuries, so the hard primer is not absolute insurance against a slamfire.

Tell me more.

Slamfires in military M14's are absolutely underreported and considered mythical on some forums.

So, what happened?

quote:

Originally posted by SlamFire:

quote:

One was an M14 using military issue ammo in which the shooter received some serious injuries, so the hard primer is not absolute insurance against a slamfire.

Tell me more.

Slamfires in military M14's are absolutely underreported and considered mythical on some forums.

So, what happened?

A very good friend was present and gave the following account based on his observations:

quote:

I was on the point just to the right at 600 yards during the State Service Rifle matches. A junior was shooting a DCM arsenal built State NM M14 using Spanish Berdan primed NATO ball Mexican match with 168 grain Sierras.
Apparently there was a sensitive primer on a singly hand fed round in the
chamber that got impacted by the firing pin before bolt lockup when when
the kid released the bolt with the bolt release. There was an empty
magazine in the rifle that got damaged along with the bolt and op rod. I
don't think the action or barrel was damaged beyond use but the stock was
splintered and the shooter got a bruised left arm and minor abrasions and
splinters through his 10X tan cloth shooting jacket. I remember hearing
this unusual explosion on my left and getting hit by stock hardware and
bolt roller parts that ended up on my mat, I looked over and the kid was
lying there with a stunned look on his face with his rifle stock bent down
at the action and smoke rising out of the left sleeve of his coat.
Luckily he was wearing glasses and the closed back end of the action
controlled most of the blowback so he suffered only minor injuries and
major questioning from his laundry lady! It is my opinion that it was a
classic M1/M14 premature firing pin impact before bolt closure into full
battery.

Regards,
hm

Very interesting. NATO ammunition in a DCM M14, hard to get more mil spec than that.

Really appreciate the report, I will use it in the future.

Best Wishes.

Dropping rounds into the chamber and letting the bolt slam closed is not a good idea on any semi auto.

Have been shooting Garands and reloading for them 25 years. I have never used CCI milspec primers, usually Winchester Primers. For many years (15), I never used a SLED, but loaded single shots by dropping rounds into the chamber and letting the bolt fly. I have always full length resized using RCBS standard dies and Remington or LC brass. Never had a slam fire or doubling. Not once.

quote:

Originally posted by A7Dave:
Have been shooting Garands and reloading for them 25 years. I have never used CCI milspec primers, usually Winchester Primers. For many years (15), I never used a SLED, but loaded single shots by dropping rounds into the chamber and letting the bolt fly. I have always full length resized using RCBS standard dies and Remington or LC brass. Never had a slam fire or doubling. Not once.

I was issued my first M1 in 1954 and fired thousands of rounds of government issued M2 Ball, M72 Match, AP and thousands more rounds of reloaded ammo in my personal M1's in competition. Even used Federal 210's (until I learned a bit more about primer characteristics) for a number of years and, I too, have not had a single slamfire, but it just takes one to ruin your day.

Having said that, I now use CCI 34's as an extra precaution. I didn't need glasses to see until I was about 55 years old either, but I wore shooting glasses all those years just the same.

This story was related on another forum and while not a slamfire, nor a gas gun, for that matter, will give one pause regarding shooting safety measures.

quote:

made a mistake last fall when i grabbed the wrong powder can.

nearly lost both my eyes. still have hundreds of particles embedded in my eyes. the one eye has "large" particles the other mostly smaller ones. the doc says unless they rust and interfere with the vision, they can stay there.

the last thing i saw before it all went black, was a bright yellow flash. i dont do painkillers, but i needed them for my eyes. doc said i burned the surface of the eye off.

Not trying to find fault, just sayin'

Regards,
hm