How Common Are Slam Fires or Dropped Rifles Going Off?

[HGM22]

How common is it for a rifle to fire simply from chambering a round or dropping/hitting it hard? I'm thinking specifically of AR and AK pattern rifles, but all rifles not utilizing some sort of firing pin restraining device are game.

Are there some rifles more likely to slam fire or go off when dropped? I know the SKS comes up frequently... What makes a rifle more likely to go off over a different one?

One of my concerns over using an AR15 for home defense is having a round slam fire during administrative loading of the weapon. A bigger concern is having a round discharge accidentally if the rifle bumps into something hard or gets dropped on say tile.

What would happen if you slammed an AR15 into a brick wall as hard as you could muzzle first? What about hitting the stock with a hammer as hard as you could?

 

[Lafitte]

I haven't known of the problem at all with factory stock rifles that are properly maintained. With some highly modified or home brew arms it may be a totally different scene.

Lafitte

 

[carbine85]

Both rifles you mention are not known for slam fires but anything can happen at any time. The AR15 is one of the safest rifles on the market IMHO. Using the safety goes a long way. The SKS is notorious slam fire for a number of reasons.

 

[entropy]

How common is it for a rifle to fire simply from chambering a round or dropping/hitting it hard? I'm thinking specifically of AR and AK pattern rifles, but all rifles not utilizing some sort of firing pin restraining device are game.

Are there some rifles more likely to slam fire or go off when dropped? I know the SKS comes up frequently... What makes a rifle more likely to go off over a different one?

One of my concerns over using an AR15 for home defense is having a round slam fire during administrative loading of the weapon. A bigger concern is having a round discharge accidentally if the rifle bumps into something hard or gets dropped on say tile.

What would happen if you slammed an AR15 into a brick wall as hard as you could muzzle first? What about hitting the stock with a hammer as hard as you could?

If you'd have stayed awake in physics class, you'd know the answer to the last two questions, at least.

The most common 'slamfire' with SKS's is when the firing pin gets gummed up with the 'cosmoline' they came with that never got cleaned out, then someone fires it enought to 'glue' the firing pin forward, causing it to 'machine gun' . It's very exciting to watch, as long as the firer has good muzzle disicpline.

 

[Sam1911]

Most "drop testing" of guns shows that there's not enough inertia and momentum involved to fire a round when a gun is dropped, thrown, or hammered into a wall or the ground. Even SKSs.

As entropy said the SKS's reputation for slam fires comes entirely from heavy storage grease locking up the innerds of the bolt and holding the firing pin forward. It turns suddenly into the equivalent of an open-bolt machine gun with a fixed firing pin, and simply lights off the next primer every time the bolt slams shut.

Proper cleaning of all those parts -- usually just once after the rifle comes out of storage -- pretty much eliminates that problem.

 

[jmorris]

How common is it for a rifle to fire simply from chambering a round or dropping/hitting it hard?

I have never had it happen nor seen it happen in my life, with a properly functioning rifle. Other than "grounding" a firearm on safe in 3gun matches, the only time I "drop" them is to make sure they are still safe testing them after a trigger adjustment.

I have seen more than a few AD's though but that is operator error.

 

[yugorpk]

I dumped half a magazine with my AR57 using too stiff of a buffer spring after the first trigger pull. Had to grab the cocking lever and pull it back t keep it from emptying the rest. Big faux pas at an indoor public range.

 

[joem1945]

I had 2 slam fires with a SKS. Both were stove pipes but a freah round in the chamber and bolt jammed part forward. Safety on, pointed down range, plier to pull the empty out. On pulling the empty out bolt slammed home and fired a round. Firing pin free but hammer follow through fired it I think. After I replaced the gas valve no more problems with stove pipes.

 

[Tirod]

The firing pin of the AR cannot protrude far enough until the bolt completely rotates and closes. That means the firing pin itself would have to be jammed forward hard enough to poke the primer. Since it's free floating it won't.

Some have cautioned that using soft primers in the AR could increase the possibility of it happening, there's no test to prove it.

On the other hand. plenty will tell you ANY exposed hammer firearm has the potential to go off if it's dropped on the hammer.

For the most part, all of that doesn't even rank in the dozen causes - operator error is the #1 cause. Dirty weapon with sticky parts vs finger on the trigger at the wrong time - take your pick. Regardless, you and I are the #1 cause of it going off when it shouldn't - hence the rules of safety.

The guns and designers do a pretty good job of keeping us from it - but we manage it all the same. The latest version? Speed reholstering of appendix carry guns in a training class. Just don't.

We will likely discharge the gun in error long before we drop it and it goes off.

 

[Slamfire]

Slamfires due to sensitive primers are very rare, but they happen. The kinetic energy of the firing pin must be matched to primer sensitivity or slamfires will occur. Commercial primers are very sensitive, primarily due to all the old, worn out firearms in the hands of the public. When a 100 year old mainspring won't ignite a cartridge, or an inadequately designed ignition mechanism won't ignite a cartridge, the first thing the shooter does is blame the ammunition. Commercial ammunition manufacturers therefore have an incentive to make their primers are sensitive as possible. Therefore with primers that are more sensitive on the average, the chance exists that a free floating firing pin will ignite a very sensitive primer by chambering a round, or dropping a weapon. If you happen to shoot yourself, have an accidental discharge, or your Garand based firearm goes off out of battery, ammunition manufacturer's have virtually no liability because proving the primer was defective, is a little hard to prove, after the fact.

Slamfire deniers are irrational people, and there are a lot of them. From what I can tell, they fall into four categories:

1) they have never seen a slamfire therefore they do not exist. I have never seen a black swan, so does that prove they don't exist? (they do)

2) They have been taught that only shooter negligence cause slamfires. The US Army taught the American public this nonsense. I call it Davidism after the last author who wrote an Dobe Bag article in the American Rifleman. The Prime Davidian wrote an article claiming the Garand mechanism was perfect, and that slam fires were only due to shoot negligence. This guy had an amazing background. He worked at Frankfort Arsenal his entire career, he was the Government Technical Expert during the Ichord hearings, and he was the lead into the investigation of the M16 slamfire issue. He created the technical specifications that required a less sensitive primer for the M16 mechanism, the #41 primer. And yet, decades later, when he was retired and working as a Army consultant, writing for the NRA, Army weapons are perfect, the M1 Garand can't slamfire, in battery or out of battery, and there is no such thing a primer sensitivity. By the absence of information, generations of shooters believe that a primer is a primer is a primer. Generations believe this nonsense, and when you have an authority figures such as the Army and the NRA actively providing dis information by "educating" us that guns can't slamfire by design, well, whom are they to believe, and whom will they believe?

C. Ed Harris was an American Rifleman technical writer from the 70's and he is a Davidian to the core. You can read his post, complete with bold print and spouting specifications, to impress the reader, about how the only thing that causes Garands/M1a's/ mini M14's to slamfire is your "worn out gun and sloppy ammunition."

http://www.thehighroad.org/showpost.php?p=6534244&postcount=7
M1A M-14 slam fire

I have examined several M1 Garand, Ruger Mini-14 and M1A rifles which have slam-fired.

All such incidents I am personally aware of occurred using handloads.

1) While soft primers may be a contributing factor, this is not the sole explanation.

2) If primers are not seated below flush of the case head, protrusion of the primer cup above the case head is a factor.

3) If cases are not sized and trimmed properly, so that there is resistance to full bolt closure and lockup, this is another factor. Both sized cases and loaded rounds should be gaged 100%. Use of military ammunition in minimum SAAMI or custom "match" chambers can also cause tolerance stacking interference.

4) When the rifle is properly assembled, with correct parts which gage properly, the firing pin should be flush or below the bolt face at "half-lock" (7-1/2 degrees bolt rotation on the M14). This is measured using a stripped bolt and slave slide-handle using a dial indicator gage inserted from the muzzle.

5) When M1a parts guns are assembled with surplus parts which may have been rejected because they didn't gage up, this is a big factor.

6) If the firing pin retraction cam in the receiver web doesn't gage properly this is another factor.

7) If the "tail" of the firing pin which engages the receiver retraction cam does not gage properly, this is a factor.

8) If primer pockets are loose from repeated reloads of brass having head hardness less than 170Vickers Diamond Pyramid Hardness, loose primers, or blown primers which leave debris in the bolt face can also cause a slam-fire.

Slam-fires have not to my knowledge been documented in properly assembled rifles in which all parts in the assembly meet the government gages, when using either NATO, US military or SAAMI specification commercial match ammunition, such as M80, L2A2, M118, M852 or Federal #308M.

An exact attributing cause of any slamfire is often impossible to determine because of interaction of multiple variables and the fact that "the Brass Fairy" often removes much of the evidence.
__________________
In Home Mix We Trust
From the Home of Ed's Red
73 de KE4SKY
________________________________________
Last edited by Ed Harris; June 3, 2010 at 09:37 AM.

When the very top authorities are telling us only shooter negligence causes slamfires, who is going to challenge them that they are full of beans? It turns out debunking authority figures is not something people want to do, it is thankless, and unprofitable. One must also understand the power of "Group Think". Humans are social creatures: we want to fit in the group. We want to be accepted by the group. If the leaders of a group espouse a certain belief system, humans will change their behavior, thinking, and beliefs to fit into the group. Humans will accept the theories of a group, will not challenge the dominant authorities, even when the evidence before their eyes shows that the group theories are wrong.

3) irrational people who don't want to believe that their rifle could accidentally discharge even though they did "everything right". These irrational people typically use Federal primers in their semi automatic rifles and don't want to change. Federal primers are the most sensitive primer on the market and are the most slamfiring primer in the United States. The third type of slamfire denier justifies their use of the most sensitive primer in their mechanism by deigning that primer initiated slamfires happen. I also believe these types need to feel that nature, the future, has to be 100% predictable, so they won't accept that unexpected events, like slamfires, can happen. Call it denial.

4) The fourth category is psychopaths who want to hurt people. <deleted>

SKS -- worth it?

http://www.thehighroad.org/showthread.php?p=9816391#post9816391
February 23, 2015, 01:10 PM PM #43

Sunray

1). Not an issue. Slam fires are not caused by rifles. They're caused by improperly loaded ammo. Usually high primers.
2) An SKS is not and never has been a target rifle. They were made to be issued as stop gap semi-autos to illiterate conscripts, who could be taught to use 'em in as little time as possible. Trigger pull(and sights) meant nothing.
"...any chance getting more cheap surplus SKSs..." Not with King Obama in office. You likely wouldn't want a rifle from Vietnam or Cuba anyway.
"...poor man's M1 Garand..." Poor mans M1 Carbine.

PM #44
Cee Zee
: August 23, 2012
Posts: 3,297

:
Not an issue. Slam fires are not caused by rifles. They're caused by improperly loaded ammo. Usually high primers.

Sorry friend but that is totally and completely wrong when talking an SKS. How many examples would you like of people who have been shooting them for decades saying what you just said is wrong? …

But just for the record I think I should include some quotes form people about the slam fire issues.

Start on this web page.

Then maybe watch this video.

Or this video.

And here's Murray's famous page on the subject.

And there's this web page which has a video.

Google lists 112,000 results on the subject. I think these people can't all be wrong. Besides I've seen this issue myself. I've seen bent firing pins and I've seen guns fired so many times the bolt got completely gunked up to the point I was surprised it would fire at all. But it did.

Friend you are giving out dangerous advice.

Sunray had been giving the same bad advice for decades, and continues to give the same bad advice, all you have to do is search and see his posts. The good guys at Canadian Gun Nutz finally figured out his malevolent personality and eventually banned him from their forum.

Some things are not funny, you can have him back


http://www.canadiangunnutz.com/foru...me-things-are-not-funny-you-can-have-him-back

09-12-2015

Cleftwynd

As long as Sunray isn't here, I am at least partially pleased. Too bad he can navigate the web and spread false and dangerous information on other sites though.

Originally Posted by laker415

He is dedicated at providing terrible advice. I wonder if he thinks he knows it all or is purposely providing poor information. He drops some bad info in a thread and never seems to return to read everyone ripping apart his stupidity.

It's what's known as seagull commenting- flys in, drops a bunch of crap that gets everybody riled up, then flys off to crap on somebody else

If there is a serious mismatch between primer sensitivity and the kinetic energy of the firing pin, the frequency of slamfires will be high enough, that it becomes obvious that slamfires due to high primer sensitivity are occurring. This is obvious in the case of foreign service rifles. These weapons often have heavy firing pins and the issue ammunition used very insensitive primers. American's get these things, use very sensitive commercial primers, and the weapons malfunction.These are some examples:

MAS 49-56 Slamfires

http://www.thehighroad.org/showthread.php?t=665024&highlight=French+7.5+Bullet+Diameter+info+Request

http://web.archive.org/web/20060506045913/http://members.nuvox.net/~on.melchar/75french/sainfo.html

These articles were available on-line, but the links are dead, so I copied
my post from an other board (two posts here as we are limited to 20000 characters):

Disclaimer: This article contains information that may not be appropriate for your particular firearm. Consult your gunsmith in regards to the safety of firing your particular firearm. Consult your reloading manuals for all safety procedures when reloading ammunition. We are not responsible for typographic errors. Your mileage may vary.

What follows is a reproduction of an article from Handloading Magazine on the 7.5x54 MAS, prefaced with comments by myself, updating the magazine article with considerations for the MAS semi-auto rifles.

Update: Reloading the 7.5x54 MAS.
By Paul Pelfrey

While the reprinted article that follows is essentially accurate, the author did not take into consideration the availability of the various semi-auto French rifles that would later be on the market at an affordable price. This article should be applicable to the MAS-44, MAS-49 and the recently imported MAS-49/56 rifles. With the data in table II of the article below, I didn’t need to reinvent the wheel to start my experimentation. My load was the 150 grain Sierra FMJ spitzer, loaded on Norma brass, with Winchester WLR primers, packed with 44 grains of AA-2520 powder. I had had a good experience with this load through my MAS-36 bolt action rifle and decided to give it a go in the MAS-49/56. The MAS-49/56 I had acquired came from SOG and was still in the arsenal wrapping when I received it. After a thorough cleaning I took it and 50 rounds of my handloads. I first test fired the rifle with some surplus Syrian ammo I had. I was disappointed. The Syrian ammo was rife with hangfires and dead primers, and those rounds that did fire would not actuate the bolt properly. Most of the rounds stovepiped none ejected fully. I then took my handloads, loading a single round in the magazine at a time and easing the bolt forward. To my delight, the rounds were rather accurate, keeping inside 1.5 inches at 50 yards, and the brass ejected cleanly. After 10 shots loaded one at a time I loaded two rounds. This time, I let the bolt fly forward on it's own to chamber the first round. The round immediately slamfired as the bolt closed, and the second round chambered. My finger had been outside the trigger guard. I unloaded the gun, then reloaded two rounds. This time, the round did not fire when chambered. However, when I pulled the trigger, the rifle fired both rounds in rapid succession. My first thought was that this was a repeat of a phenomenon that I had experienced with an SKS carbine. In that case, the modern lube I had used on the SKS was too slippery and allowed the firing pin to travel forward with the bolt actuation with sufficient inertia to impact and detonate the primer. In that case, removal of the lubrication solved the problem. I disassembled the MAS rifle and dried the components completely and reassembled it. The slamfire problem persisted. My attention turned to the handloads. Checking the primer seating depth and dimensions of the case turned up nothing out of spec (except the smaller rim diameter, per the Handloader article). I then chambered a Syrian round and then removed it. Examining the Syrian round showed a slight indentation on the primer. I then left the range to ponder my next move.

Next weekend I returned with more handloads, this time using CCI regular and match primers, and Remington primers. During this session my handloads still suffered from slamfires while the military French and Syrian ammo did not. Conclusion: Commercial primers are too thin to operate safely in the French MAS semi-auto rifles.

Solution: CCI, under the name of their parent company, Blount, manufactures a military spec primer. I found a brick at a gunshow in a plain white box. The label read "1000 M-34 Primer for 7.62mm Cartridge". Loading 50 more rounds with these primers solved the problem. Not a single slamfire. Most distributors do not carry this primer, and will only order and sell it in a case lot (5000 primers). The good news is that these primers sell for only about $6-$9 more than the same quantity of regular primers. I would recommend their use in any round that might be loaded in a semi-auto rifle, just for an added margin of safety.

Reloading this round has become much cheaper since the publication of the Handloader article. Lee now makes the dies for this round, and I have seen a retail store price on them for $29.99 (half of RCBS). After talking to the techs at Lee, they are willing to make a tapered expander for necking up the Swedish brass for $15, and if you send them a formed cased with a bullet (no primer, no powder) they will make one of their Factory Crimp Dies for it for $25. I recommend this, inasmuch as a few of my handloads had a problem with the bullets being pushed back into the case upon chambering. This can lead to overpressure and possible injury. Brass is more plentiful now as well. I find Remington 6.5 Swedish at shows for $27/100 and Kengs in Georgia also stocks Lapua 6.5 Swedish for a similar price.

20 Feb 2008 Shotgun News,
Article “ Micro Galil, The Ultimate Krinkov”
Author Peter Kokalis
Page 12

“Most Kalashnikovs have inertia firing pins, without an associated spring. The initial lot of Galils brought into this country by Magnum Research INC. also had no firing pin springs. The Micro Galils that I examined in El Salvador were not equipped with spring-loaded firing pins either.

Military small arms ammunition primers usually have relatively hard cups, which are not easily touched off. American commercial cal .223 Rem ammunition, including Winchester ammunition often features fairly soft primer cups. In 1983, Winchester ammunition in particular caused several slam-fires and all Galils offered for sale in the United States were quickly retrofitted with strong firing pin strings. “

29 August 2007

CENTURY INTERNATIONAL ARMS, INC.
236 Bryce Boulevard
Fairfax, Vermont, U.S.A. 05454
Tel: (802) 527-1252 Fax: (802) 527-5631
Date: August 29, 2007
Subject: Galil and/or Golani Semi-Auto Sporter Rifle
We are requesting that customers who purchased the Galil and/or Golani Semi-Auto
Sporter that have serial numbers between GAL00001 and GAL02393 send in their
firearm to us as we have modified the bolt and are installing a new firing pin and firing
pin spring to ensure that your Golani offers you the utmost safety and reliability. All Galil
and/or Golani rifles that have the letter "F" or "X" on the bottom of the receiver front cut
off have already been upgraded and your rifle does not need to be sent in to us.If you
are a dealer, please provide us with the names, addresses and contact information of
the purchasers of these Galil/Golani rifles. We will contact them directly. If you are
contacted by these customers, please have them call us at 1-800-270-2767 to obtain a
return authorization. We appreciate your cooperation in this matter and hope to have
this situation resolved as quickly as possible[/b]

http://www.xdtalk.com/forums/ak-47-talk/89974-ak-slam-fire-question.html

AK slam fire question

11-05-2008 Hi guys

I thought I would throw this out there to see what you guys think might be causing a slam fire with my AK.

I took my Romy G to the local range to sight her in. I loaded up the mag with 3 rounds each time 40 rounds total. On two occasions after I fired the first shot the second went off right away. I can only describe this as a slam fire. It seems that when I fired a round something happened when chambering the new round and caused the second one to go off without pulling the trigger. I was using Winchester
White Box 7.62x39 (local range doesn’t allow wolf which is of course what I have plenty of)

11-10-2008

So I cleaned it all up and checked over the FCG real close and everything seems to be in working order. I am not getting the "hammer follow" issue. The disconnector is retaining the hammer when the trigger is fully depressed. And the trigger hook is is grabbing the front of the hammer.

I also took the bolt down and cleaned it up real nice.

I took it to the range over the weekend and put about 90 rounds of wolf down range and not a single issue. Nothing that resembled what happend when using the Winchseter ammo. I did check one of the rounds that were chambered to see if there were any marks on the primer and there was but it didnt go off.

Tavor 21 Slamfire video on youtube.

Notice how many rounds the guy fires. If he had a mechanical problem he would have recurring slamfires, but he did not. When you see the slamfire, notice that the finger is not on the trigger. He was running Federal American Eagle (federal primers) and Winchester ammo. Winchester redesigned their primers in 1999 to make them more sensitive.

This weapon slamfired in battery.

http://www.youtube.com/watch?v=_cv7BI3wGWA

 

[AK103K]

The firing pin of the AR cannot protrude far enough until the bolt completely rotates and closes. That means the firing pin itself would have to be jammed forward hard enough to poke the primer. Since it's free floating it won't.

Some have cautioned that using soft primers in the AR could increase the possibility of it happening, there's no test to prove it.

There is a simple test, try out what you intend to shoot in the gun and vet it.

I ran into some problems with Winchester small rifle primers in my Armalite AR. I ran out of my normal CCI primers during the last shortage, and found a supply of Winchester primers and used them instead.

I also had just picked up a new suppressor, and at first, was thinking that was the issue. The rifle loaded fine, but on the first pull of the trigger, I got a 3-4 round burst. Wasnt expecting that. From that point on, I was getting intermittent bursts.

I took the suppressor off, and the problem continued. I loaded some GI ammo I had along, and the problem stopped. Put the suppressor back on, and with the GI ammo, still no problem.

From that point on, I havent used the Winchester primers in my AR's, and I havent had the problem since.

Slamfire deniers are irrational people, and there are a lot of them.

Ive run into this too, and its kind of amazing that some people just dont want to hear it, and want to blame you for whatever happened.

Ive posted this a few times before, I had a DCM issue M1 come apart the first time out with it due to a slam fire, using DCM issue USGI LC ammo.

It wasnt just one either, and it wasnt until later/after the fact, that I figured out there were actually multiple slam fires prior to detonation. I was assuming it was me with a new gun, when in fact, it had actually fired out of battery a couple of times during the rapid fire stages. Lesson learned.


I think if you shoot these types of guns long enough, at some point, theres a pretty good chance you may well run into things that are disconcerting. Your fault, someone else's fault, nobodys fault, it really doesnt matter, it just is what it is. We just do our best to minimize it.

Make no mistake though, if you're careless, and/or aren't paying attention, or are doing things you shouldnt be, they will bite you, and the bite can be quite nasty.

 

[TimSr]

The most common 'slamfire' with SKS's is when the firing pin gets gummed up with the 'cosmoline' they came with that never got cleaned out, then someone fires it enought to 'glue' the firing pin forward, causing it to 'machine gun' . It's very exciting to watch, as long as the firer has good muzzle disicpline.

LOL! Were you there that day? Never had any problems with mine until I decided to play with it on that very cold day when that 20 year old grease turned to gum. Took bolt apart, cleaned it, and lubed with Remoil and proablme never returned.

 

[Slamfire]

Quote:

Slamfire deniers are irrational people, and there are a lot of them.

Ive run into this too, and its kind of amazing that some people just dont want to hear it, and want to blame you for whatever happened.

Ive posted this a few times before, I had a DCM issue M1 come apart the first time out with it due to a slam fire, using DCM issue USGI LC ammo.

It wasnt just one either, and it wasnt until later/after the fact, that I figured out there were actually multiple slam fires prior to detonation. I was assuming it was me with a new gun, when in fact, it had actually fired out of battery a couple of times during the rapid fire stages. Lesson learned.

I have always appreciated your testimony and of course, your support on this. Having others who experienced a slamfire post their testimony helps counteract the angry denialism of the irrational, and the lies of the psychopaths. Thought it is difficult to know if truth has any effect on any of them, it may on those who are not ideologically committed.

 

[macgrumpy]

angry denialism of the irrational, and the lies of the psychopaths

Well then, I guess the slamfire issue is settled science.

What a perfect example of Saul Alinsky's "Rules for Radicals"

RULE 5: “Ridicule is man’s most potent weapon.” There is no defense. It’s irrational. It’s infuriating. It also works as a key pressure point to force the enemy into concessions.

I don't listen to anybody that thinks ridiculing others is the way to win an argument.


I spent several years as a Range Master on a public range supervising as many as 800 shooters per day and I never saw a customer with a slamfire. Do they happen? Yes, but not very often and then only when there is a mechanical problem with the rifle and/or ammo. As long as you follow proper handling procedures and your firearm is mechanically sound you wont ever have a problem, period.

 

[Slamfire]

For those who are interested in the drop distance it takes for a series 70 M1911 to slamfire, Drake Gunworks conducted some very interesting drop tests:

Drop Test Results
http://www.1911.net16.net/drop1/drop1.htm


Drake Odham posted the results and a video. The video now is gone as the web page it was posted on is no longer active. Mr Odhan no longer has the entire study on his web site, maybe angry, irrational, denialists forced him to take it down. http://www.drakesgunworks.com/

If the hypothesis is that kinetic energy of the firing pin causes some type of slamfires, then this theory is well supported by Mr Odham's tests. If you review his data what you see is that the heavier the firing pin, the less drop distance is needed to achieve a slamfire. Also, the harder the impact surface, the less drop distance is needed to achieve a slamfire. Both of these test situations would increase the kinetic energy of the firing pin as it moves forward to rebound off the firing pin.

Also, something not acknowledged by slamfire denialists, is that primers vary in sensitivity. Not merely by brand, but by lot and within the lot. Some primers are less sensitive than others , others are more sensitive. The absolute best book I have read about primer construction, sensitivity, is George Frost's book: Ammunition Making. Denialists don't read materials that conflict with their theories, but others who are interested in learning about ammunition production and testing will find this book very interesting. It is the only book that tells you how to make primer cake! Something I don't recommend anyone doing as the stuff is dangerous.

<deleted>

 

[AK103K]

I don't listen to anybody that thinks ridiculing others is the way to win an argument.

I think youre misunderstanding the comment. Its a response thats specifically addressing what youre referring to.

In most cases, its those who refute that slam fires occur, that are doing the "ridiculing".

Id suggest you do some reading up on some of what Slamfire has posted in the past, and youll have a better idea as to whats going on, and whats being referred to. Not to mention, what he has contributed.

As long as you follow proper handling procedures and your firearm is mechanically sound you wont ever have a problem, period.

There was a time I believed that, I now know better.

We (most of us anyway, I would think) try our best to do as you suggest, but there will always be that "but".

 

[ColoradoShooter77]

I made the mistake of using CCI 400 primers in full house Nato handload's.....fired 40 rounds and didn't have a slam-fire in my AR.

This was with 26 grains AA-2460 behind a 55 grain FMJ.

I now use CCI 450's for all of my 5.56 loads.

 

[sawdeanz]

There was a thread not too long ago about a poster who had an AR with the bolt locked open and full magazine next to his bed. I guess this was his ready condition. Slam fire when it fell over/off his table.

Frankly I'm kinda concerned/curious why firing pin blocks are a now nearly universal feature for handguns and almost non-existent in even modern rifles. I feel like there would be just as much opportunity to drop a rifle as there was a pistol during serious use.

 

[AK103K]

I normally use the CCI 400's in my .223 loads, and have also used the 450's, and the "BR-4's", if the 400's werent available, and never had an issue with using any of them in the AR's.

I usually use CCI in everything anyway, since I do load for both autos and bolt guns in the same calibers, and the CCI's have always given good results in all of them, and ease the worry with the autoloaders.

The Winchesters were only found to be a problem as I deviated from the CCI's out of necessity. Im still working through that lot, but only using them in my bolt guns, were they seem to work fine.

I dont know if that was just an over sensitive lot, or an issue with that particular gun, or a bit of both, or whatever, at this point, its just not worth the bother to me, to delve into it any further, as Im not likely those them again anyway.

 

[taliv]

The firing pin of the AR cannot protrude far enough until the bolt completely rotates and closes. That means the firing pin itself would have to be jammed forward hard enough to poke the primer. Since it's free floating it won't.

Tirod, are you thinking about OOB or slamfires?

Shoot high power and you will see some slam fires. They will definitely happen with an AR15. I minimize the "admin loading" in my house and ALWAYS keep the rifle pointed in the safest possible direction, as technically, there's not really any part of my house i want to destroy.

it's not just sensitive primers. sometimes it's reloads and people not seating them deep enough. any number of slightly out of spec parts could contribute to the problem as well. (to be honest, with half a million new AR15 manufacturers since obama got elected, I'm surprised we don't have a lot more issues with out of spec parts)

 

[Slamfire]

Frankly I'm kinda concerned/curious why firing pin blocks are a now nearly universal feature for handguns and almost non-existent in even modern rifles. I feel like there would be just as much opportunity to drop a rifle as there was a pistol during serious use.

Perhaps due to the fact pistol primers are so much more sensitive than rifle. Rifles at least have very powerful ignition systems, a combination of spring tension and hammer strike arc. The typical pistol hammer is shorter than my M1a or M1 Garand hammer, also true for my match AR15's.

It is true that high primers can cause a slamfire, but it turns out high primers are the most common cause of misfire, not slamfire. See Mysteries And Misconceptions Of The All-Important Primer by CCI: www.shootingtimes.com/ammo/ammunition_st_mamotaip_200909/

A couple of conditions have to be met for a primer to ignite. One of the first is that the anvil has to be firmly seated. If the anvil is dangling in the air, the primer is not going to ignite. Then the cup has to be pressed down, pushing the primer cake onto the anvil, setting the "bridge distance". If the bridge distance is too great, the primer will misfire. Now in the situation where a case has shallow primer pockets, then the anvil could be set, the bridge distance set, and then that primer could go off if impacted with enough force. Or, you could put spaces under your primer, raising the primer above the casehead. It is however, my opinion, that high primers are the least likely cause of slamfires, but, they cannot be dismissed entirely as they are in the realm of possibility.

Primers are not predictable no matter how much people want them to be. You can't fully trust the things.

I have no idea how a Davidian would address this accident. A primer went off in an impact puller. To me, this shows the rather caprious nature of primers and that there are primers sensitive enough that an impact puller will set them off. I suspect a Davidian will simply ignore this:


Primer goes off in inertial bullet puller on a loaded cartrige
http://www.thehighroad.org/showthread.php?t=794751

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Primer goes off in inertial bullet puller on a loaded 22-250.
Just had a close call when using a RCBS inertial bullet puller. I have been using one of these for about 30 years with out any problem. Today I was going to pull a few bullets out of loaded 22-250 ammo to change the load for testing.
I had a 50 grain Hornady V-Max on top of 37.5 grains of Varget in Hornady brass with a CCI 200 LR Primer. I smack the RCBS inertial bullet puller several times on the concrete floor and the bullet would not budge, I finally gave it a very hard hit and the primer went the Primer went off. At first I thought I might have hit a loose primer lying on the floor but could not find any burn marks, then I noticed the primer was missing out of the cartridge but the cartridge was intact with the bullet still in it. How that that be possible. I the powder did not ignite. I thought may be the primer bounced out and I smacked it on the floor, so I pulled the bullet and dumped the powder out. Sure enough several grains of powder were singed but the powder did not ignite. The primer simply went off and with out any thing to hold the primer in, it simply pushed it self out with out enough fire going thru the flash hole to set off the powder.

I have been reloading for 47 years and loaded ten of thousands of rounds. I never would have believed this would have been possible.

Has any one else ever had a primer go off by accident?

As for the AR15 design. There are very few OOB slamfire reports in the AR15. In that mechanism, the firing pin is positively retracted until cam down. Once the lugs engage, the firing can and does rebound off the primer. The Garand mechanism has a real design defect in that the firing pin can rebound off the primer any time prior to cam down. Then, of course, it can rebound off the primer once a round is chambered. This lack of a positive firing pin block is why Garands/M1a's/M1 carbines/Mini 14's all have in battery slamfires reports and out of battery slamfire reports. And have more of them than all other mechanisms combined.

 

[redneck2]

The firing pin of the AR cannot protrude far enough until the bolt completely rotates and closes. That means the firing pin itself would have to be jammed forward hard enough to poke the primer. Since it's free floating it won't.

Some have cautioned that using soft primers in the AR could increase the possibility of it happening, there's no test to prove it.

Bull crap. My friend's AR slam fired. Dropped the bolt on a single round that was not stripped from the mag. Federal primer. I was right beside him. Had just told him not to drop the bolt by releasing the catch, but he did it anyway.

Drop the bolt without stripping a round and you are inviting a slam fire.

 

[Welding Rod]

I have been present for 3 slam fires, and one kaboom. I was watching a friend let the bolt go on a Russian mil-surp semi-auto of some kind. He was using new American factory match ammo. Blam there goes one over the berm.

During a Garand match I was shooting in a guy had a SF. I am pretty sure he let the bolt go from the fully rearward position during single loading. Not using a SLED.

I forget what gun the 3rd one was... But it was a semi-auto in a service rifle match.

The kaboom was an AR.

 

[mf-dif]

My SKS slam fired and did a nice 3-round burst luckily as I was pointing it down range. I thought the bolt was clean, it passed the rattle test, but guess not. Afterwards I disassembled the bolt completely...which is a pain in the ass. Then let it sit in Hoppes for a night.

I've seen an AR15 slam fire during a torture test. It was thrown off a 30-ft hill, hit the ground, and popped off the round in the chamber. Safety was on. But that's pretty extreme. I wouldn't worry about it.

 

[entropy]

LOL! Were you there that day? Never had any problems with mine until I decided to play with it on that very cold day when that 20 year old grease turned to gum. Took bolt apart, cleaned it, and lubed with Remoil and proablme never returned.

Not for yours, unless you were up in Wisconsin when it happened. But it was on a cold day, with an SKS that had never been properly disassembled and cleaned. The two of us not firing it laughed for a bit, and I cleaned it up properly for him; least I could do for the entertainment.