AR slamfire using CCI SR primer - pic included

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Did you fully disassemble the bolt and clean out all the grease/crud from within the firing pin channel?
Yes.
Cosmoline is wax like petroleum substance that melts in water above 150 deg F and floats, this is a effective way of getting rid of it.
 
These are AR15 slamfire accounts I have collected over the years. As you can read, AR15's slamfire.

AR15 slamfire with Winchester primers.

http://www.thehighroad.org/showthread.php?p=4627417

Occured today while breaking in a new upper ... single round in the mag, pressed the release and ... BANG! A little later on, with three rounds in the mag, pressed the trigger ... round fired. Everything is ok. Pressed the trigger again ... double BANG!

I went back to single loading to finish out the box. Total rounds fired ... 40. Two slam-fires (including the double). Two failures to extract. One failure to feed.

First slam-fire was on the second round fired (while I was still single loading the magazines). The double was on rounds 27, 28 (of 40).

At this point the ammunition is my prime suspect, Winchester "White Box" .223 Rem, 62 grain but I would have to say that ARs do, in fact, slam-fire.

I did inspect for a frozen pin after the first slam fire. I didn't expect one (frozen pin) since I had personally cleaned and inspected the gun last night and it was the second round of the day. I also didn't expect it to foul up too much since it is a piston operated upper (ZM Weapons).

The upper was brand new and unfired (except for factory). The lower is a relatively new (about 200 rounds) RRA. Both (upper and lower) were cleaned, inspected and lubricated properly before the trip to the range. The lower has functioned flawlessly for those 200 rounds when mated to a White Oak Armament upper (all Black Hills .223 Rem 77 grain).

I know BR said that the bolt face could cause the slam fire but the two casings did have firing pin strikes with no other dimples or scratches on the primer face.

I am begining to suspect the recoil spring on the ZM upper. It does seem rather robust. This upper might require the harder primers found in 5.56 NATO. Unfortunately I don't know it all yet so I'm still researching.


Watched an AR Slam-Fire Saturday

Posted 20 http://www.usrifleteams.com/forums/index.php?showtopic=13132&view=&hl=slamfire&fromsearch=1 April 2009 - 09:10 AM

I was scoring my firing-point partner Saturday during offhand and he had a slam-fire on about the 5th round. We're talking about an experienced shooter here. Multi-year state HP champion, generally shoots 199-clean offhand, not to mention he's a hell of a nice guy. The bullet hit the dirt about 10 yards in front of the firing line. I was watching him closely trying to learn something from his technique, but didn't expect to learn this. I know his finger was off the trigger for certain but his muzzle was decidedly pointed earthward when he closed the bolt. The area downrange is uninhabited for many miles, so at this range folks are a bit lax about closing the bolt while rifle is pointed toward the impact area. After that, he was pretty careful about keeping it level. He was shooting an AR spacegun. He thought it might have been due to the bolt carrier weight he had just put in for testing before this match. My suspicion is high primer, but he could be right. Another possibility is his loading technique. He places the round through the ejection port, then tips the muzzle down and jiggles the round fully into the chamber prior to closing the bolt. I have always thought it best to leave the cartridge on top of the magazine and let the bolt "strip" and chamber it from it's "natural" position. In any event, let this be a lesson to all of us. Closing the bolt is an inherently risky event. Point yer rifle at the backstop when you push that button. My buddy lost the match as a result of his slam-fire, but next time it could be a lot worse.

Posted 30 May 2009 - 08:09 AM

I am the person Heman referred to having a slam fire on a bolt rifle. The rifle in question is a Stolle BB Panda action with a Kelbly trigger set at 14 oz. The system is two years old and has several thousand live rounds through it as well as countless dry fires. After the match, I re-weighed the trigger and it still breaks at 14 oz. The only thing that was found was a very small piece of dirt on the sear engagement notch, but I doubt that this was the cause of the slam fire. I tried to re-create the condition 8-10 time on the line, without success, then again at home. I KNOW I didn't have my finger on the trigger when I closed the bolt, so that scenario isn't a suspect either. I just returned from a two day Palma style match where I fired over 100 rounds and not a single hick-up with the system. I guess it will just get chalked up to one of life’s great mysteries.
Be safe,
Lloyd

http://www.arizonashooting.com/v3/v...sid=588d04cdaf6def94be9f899784f80c31&start=15

12 April 2011

I have had ARs fire unintentionally before when the bolt hold-open is released and the bolt slams home. Usually this has happened with reloads, due to use of soft commercial primers and the free-floating firing pin design of the weapon. The milspec primers are slightly harder to prevent just such events. Many claim that the low wieght of the alloy pin makes this unlikely,...but I've experienced it and know better. Nearly took my big toe off once when I releoaded a fresh mag and let the bolt fly home (finger off the trigger, of course).

If the weapon had seen a lot of rounds fired since the last cleaning, the carbon fouling build up that the direct gas system is notorious for could have slowed the rotating and closing of the bolt just enough, that when the sudden slowing of the bolt assembly's forward movent allowed the free-floating firing pin to hit forward on the soft commercial primer,...detonation occurred before complete locking of the breach.


Posted 20 April 2009 - 10:43 AM
Gary,

I disagree.

It's happened to me.

I've found that dropping the round entirely into the chamber and letting the bolt close with full momentum isn't the best idea.

I now leave the round resting on the magazine and let the bolt "pick it up" as it closes.

Free-floating firing pins and occasionally sensitive primers can lead to this.


Pamf,
Gary brings up a good point about the trigger issue. Another consideration is the primer. I have seen 2 slamfires in an AR15. Both occured during an offhand string, 2 shots in a row. The shooter is a very experienced reloader and highpower shooter. It never happened again to him. He was using WSR primers. Perhaps it was the primer's "sensitivity," a couple of high primers, or a combo of the two.
The occurance sure did shake his nerves though. Both rounds impacted 10-20 yds in front of the firing line.
JW

Posted 20 April 2009 - 12:02 PM
I had it a few years ago practicing off hand with winchester white box in my service rifle.

Second shot of the night, shot went into the ground in front of me. I put the rifle down and tracked down my 2 ejected brass. Looking at the primer strikes, one had metal flow out into the firing pin hole in the front of the bolt. So, instead of a primer srike like an innie belly button, one of the brass had an outie. No damage to the rifle.

Whats most amazing about your post PamF is the 199 to 200 part!

Ryan


Posted 20 April 2009 - 12:46 PM

I've had two slam fires and both of them scared the beejiminees outta me. One of the more experienced shooters in my club made the observation that slams seem to happen more often when the muzzle is depresseed as the bolt goes forward. He postulated that the firing pin is already lying forward from gravity almost as if it was preloaded. He figured that as the bolt rode forward with the pin already out, if the primer was gonna go that just gave it the extra opportunity to do so. Since that time I've never let the bolt go forward with the muzzle depressed. I have no idea whether his idea has any merit but it makes me feel safer. For what that's worth. LOL

Posted 22 April 2009 - 11:06 AM

We had at least 2 MIA's over the years at New Holland that had rounds go off when the bolt was closed.

The reason I am able to think of at least 2 is the severe damage to the rifles. In the 2 listed instances the rifles were damaged to the point the receivers were cracked and or broken.

We have an AR-15 do the same thing a time or 2 a year. We have not had rifle damage from the AR-15 slam fires.

My finding at the end of the M1A era and start of the AR-15 era was to completely ensure an AR-15 will not slam fire is to install a light weight firing pin.
Sincerely,
Paul

Posted 22 April 2009 - 12:31 PM

I had a slam fire several months ago. I was just at my regular local club's range doing slow fire standing practice. Put the round in the ejection port, sort of tipped my rifle forward very quickly to let inertia start the round in the chamber and dropped the bolt. Round went off about 10 feet in front of me. I make an effort to keep the rifle parallel to the ground when dropping the bolt, but get lax about it sometimes.

I was using handloads. Hornady 75gr HPBT, 24.0gr RL15, Remington 7-1/2, LC03 brass. I'm betting the primer was a bit high, because it was once fired brass from military source and I used a Dillon Super Swage tool to just barely swage the pockets (keeping them tight as possible, but still accept a primer).

Posted 23 April 2009 - 01:58 PM

I g=had a slam fire with a Garand in the first highpower match I EVER shot. Really unnerved my. I was a reloading greenhorn, but others found some issue with the dies a friend had loaned me. learned a lot that day. I've always remembered that.

Posted 03 May 2009 - 08:52 AM

We've had only one instance in the 11 years I've ran local matches. AR15, handload. The same gun has been used many times since w/o any problems. The round impacted the ground 15 feet in front of the line - not a big problem with me compared to having the muzzle raised and the bullet leaving the range.
Me, guess like most, load with the muzzle slightly depressed, drop it in, and hit the bolt release. Bent several rounds trying to drop 'em on the follower. Haven't lost 10 points to slamfire yet, although I have employ many other methods of losing points !


Posted 29 May 2009 - 11:46 AM

I saw two slam fires by the same shooter in the same offhand string.
He was a good shooter who posted a poor score for the day because of this.
I never found out what caused this in his rifle that day but it reinforced the absolute importance of having the muzzle ALWAYS pointed in a safe direction when closing the bolt on live ammunition. (in any firearm)
Both rounds impacted the ground a few yards ahead of him but later, in the same match, I witnessed him closing his bolt with the muzzle well above the horizon. ????????

Bullets impacting the ground will tumble and have a limited flight distance but ones angled above the horizon can pose a much more serious hazard.
Trying to close the bolt with the rifle aimed at the backstop is, in my opinion, asking for trouble. I always keep my muzzle down when closing the bolt and have never experienced a slam fire in my own firearms.
Most folks close their bolts sky high during their rapids and I wish that they wouldn't


Posted 29 May 2009 - 12:33 PM
I had mine to slamfire monday while chronographing some loads. It was completely horozontile on a front rest when I loaded and closed the bolt. I'm just glad it was pointed downrange and wasn't pointed at the chronograph when I closed the bolt. Scared the crap out of me though.
Slamfire, how is it scored?

http://www.usrifleteams.com/forums/index.php?showtopic=13846&view=&hl=slamfire&fromsearch=1

Posted 21 July 2009 - 12:05 PM

How do you score or count a slamfire? Is it considered as a miss or are you allowed to fire over with another round and disreguard the slamfire? I am referring to having a slamfire while shooting slow fire 200 or 600. The reason I'm asking I have had 2 slamfires one was recorded as a miss at one range and the other one was disreguarded and I was allowed to fire another round in it's place at a different range. Just wanting to know the proper procedure. Tim


Posted 21 July 2009 - 04:05 PM

I never had this happen until I bought some CCI400 primers. The rem. 7.5 never slamfired on me. I'll be glad when the CCI's are gone.

Posted 25 July 2009 - 06:12 PM

I had it happen to me twice in the same stage of a match, standing slow fire, with the newer Winchester SR primers. I was able to borrow a friends extra amo and finish the match. I now only use Rem 71/2's at matches and have never had a problem since. The old Win SR's were harder. I have used CCI mil spec primers on my practice loads with no issues also
 
SlamFire1 - do you have any photos of firing pin indentations on slam-fired rounds? I suspect that a hammer follow - induced slamfire would result in a deeper mark than the one I see on my slam-fired round.

Rearding the high primer theory: wouldn't a high primer, where the anvil is not fully "set", be less likely to fire from a relatively weak floating firing pin strike?
 
SlamFire1 - do you have any photos of firing pin indentations on slam-fired rounds? I suspect that a hammer follow - induced slamfire would result in a deeper mark than the one I see on my slam-fired round.

Rearding the high primer theory: wouldn't a high primer, where the anvil is not fully "set", be less likely to fire from a relatively weak floating firing pin strike?
Under some circumstances the first strike will seat a high primer but it seems with semi-auto rifles with floating firing pins a high primer lends itself to causing slam-fires. I'm not an engineer so I can't explain it but from everything I've read high primers are a problem in semi-autos.
 
SlamFire1 - do you have any photos of firing pin indentations on slam-fired rounds? I suspect that a hammer follow - induced slamfire would result in a deeper mark than the one I see on my slam-fired round.

I picked up my AR15 slamfire round and my bud’s and the indentation looked like a 100% normal firing pin strike.

However, take a look at post #41 and the Winchester primers that slamfired in a piston AR. Look like yours.
http://www.thehighroad.org/showthread.php?p=4627417


Rearding the high primer theory: wouldn't a high primer, where the anvil is not fully "set", be less likely to fire from a relatively weak floating firing pin strike?
Absolutely. You can search and find threads where high primers would not go off even when hit hard by a striker mechanism. That is why I am being sarcastic about the high primer slamfire theory, it is not easy at all to get high primers to go off, unless the anvil is being supported from the bottom.
 
High Tech ammo has the CCI #41 for $130/5k. At $26/box (not including shipping/hazmat) that's much less than I can buy any brand of primer at the LGS (ours don't carry Wolf or Tula).

Buying 30k at once is kind of expensive to get the free hazmat, but 32 lbs of surplus powder will also cover the hazmat for your primers.

Even w/o buying enough to get free hazmat, just buying 10k and paying shipping & hazmat you're under $30/box which is less than I can buy any primers in the LGS after paying sales tax. The CCI #41 are much more expensive at the LGS compared to CCI #450 or any other major brand SRP. Anyway, at $10 more per 5k that's .2¢ per primer more (1¢ every 5 primers) so to me that's cheap insurance.
 
Your loads were too hot for the primer. That is the anvil sticking out.

According to this web page, the CCI #41 has a thicker cup

http://www.sksboards.com/smf/index.php?topic=56422.0

CCI/Speer Technical Services says: "The CCI 400 primer does have a thinner cup bottom than CCI 450, #41 or BR4 primers... [with] the CCI #41 primer... there is more 'distance' between the tip of the anvil and the bottom of the cup." so that is their AR15 recommendation, although it seems like there are no complaints with using the BR4 and 450 primers by AR15 shooters and reloaders, in general. The #41 just gives you a little more safety margin for free-floating firing pins and would be the best choice for commercial reloaders who have no control over the rifles their .223 ammo is used in.


You blew your anvil out of the primer. You load was very hot. I have seen this in other AR's, whenever you get close to maximum loads funny/bad things can happen.

A bud blew the anvil out of this WSR. That is his firing pin holding the case up. Like some barbeque sauce for your smoked firing pin? :D

CroppedRearcaseontopfiringpinlarger.jpg

I pierced so many brass WSR and ate up so many firing pins that I will never use them again. I would get at least one, sometimes three or more pierced WSR brass primer per rapid fire. If I used my good ole nickle plated WSR, discontinued 1999, no pierced primers for the same loads.

Since then, CCI #41's for me.
 
I have followed Slamfires advise on # 41 primers. I was almost out of the old silver WSR primers and was going to use the newer ones when I first read his posts about the differences in the new primers. That was enough to get me to buy # 41s.

And he is right, that primer with the anvil just sticking out of it is from way to much pressure, or a bad firing pin, or both.
 
SlamFire1 - what is your opinion of CCI-BR-SR primer? I understand they have a thicker cup, but I don't know if the cup to anvil distance is as long as it is in #41 primer.

If possible, I'd like to use to BR primers, as I don't want to rework my favorite loads for use with the magnum-like #41 primer.

I'm not loading anything hot, so my only goal is to reduce the possibility of pin-induced slam firing. As an added bonus, according to the table posted by WEG, they seem to be the widest of the CCI primers, which is nice, in case some of my brass starts to develop a large primer pocket from use.
 
SlamFire1 - what is your opinion of CCI-BR-SR primer? I understand they have a thicker cup, but I don't know if the cup to anvil distance is as long as it is in #41 primer.

If possible, I'd like to use to BR primers, as I don't want to rework my favorite loads for use with the magnum-like #41 primer.

I'm not loading anything hot, so my only goal is to reduce the possibility of pin-induced slam firing. As an added bonus, according to the table posted by WEG, they seem to be the widest of the CCI primers, which is nice, in case some of my brass starts to develop a large primer pocket from use.
As for the CCI benchrest primers, I have F Class Champion buds who use them in bolt rifles, lots of really good shooters use them, for me, they are too expensive and I doubt I could really see any difference on paper with them.

As for slamfires in AR15’s. Unlike Garands/M1a’s which fire out of battery, I have never heard of an out of battery slamfire in a AR type mechanism. I believe that is due to the position of the firing pin at cam down. In Garands/M1a’s, the firing pin is retracted at cam down, prior to that it is fully able to tap the primer. In AR’s the firing pin is kept retracted until cam down. There is always some lug engagement when the firing pin comes out. The difference between these mechanisms is that Garands/M1a’s sometimes slamfire in battery and sometimes out of battery. When rifles slamfire out of battery the case is unsupported and you can have a catastrophic failure of the receiver.

The highest potential in getting a AR15 slamfire is to drop a round in the chamber and hit the bolt release. The one I had and the one I saw, were during 200 SF standing. Lowering the muzzle added a little bit of extra acceleration due to gravity and believe it or not, that increases the chance of a AR slamfire. If you notice they changed the NRA loading rules years ago, used to be you could load your rifle on the shooting stool. AR shooters were placing the muzzle on the stool, dropping a round in the chamber, then hitting the bolt release. This is what happened.

http://www.thehighroad.org/showthread.php?t=526486

Today, 07:16 AM #4

Hangingrock
Member


Join Date: March 10, 2010
Location: NC
Posts: 152
A competitor on the firing line next to me was single loading his AR15 muzzle down on his shooting stool during off hand. He let the bolt go home and the rifle discharged. It didn’t do the contents of his shooting stool any good at all.

I tried to change my loading procedures. In the standing stage, when I drop a single round into the chamber I will lower the bolt half way with the charging handle and then let go. I bump the forward assist to ensure full lug rotation.

For sitting stages, I insert sighting shots in the magazine, insert mag, shoot sighter, remove mag, put round in mag, insert magazine and shoot sighter. If possible I never toss a round in the chamber and hit the bolt release.

Slow fire prone because I are laced up in a sling and I don’t want to break position, I toss a round in the chamber and hit the bolt release. I do run the risk of a slamfire, which will be scored as a big fat zero, but since my muzzle is always pointed down range in a Highpower match, that is the worst that will happen.


So, in my opinion, you can minimize the risk of the potential of a AR15 slamfire by always feeding from the magazine or not letting the bolt drop the full distance on a round in the chamber. Whenever loading one of these mechanisms ensure that nothing is in line with that muzzle. This is true for all semi auto mechanisms, at some point the firing pin becomes free floating. They all have a finite potential of an inbattery slamfire because primer sensitivity varies and a visual examination of a primer cannot not tell you if it is over sensitive of not. Cannot tell if it is going to dud either. If you shoot enough, you will have duds.

Unlike M1a’s and Garands where you risk injury, because these things will slamfire out of battery, with AR’s, the worst that will happen is a round going downrange.

The main aggravation with thin primer cups in AR’s is pierced primers which will dish your firing pin. And at $10-15.00 a firing pin, those add up.

If you ever experience a pierced primer cut your load by a ½ grain. If you get more pierced primers, continue cutting by half grain increments till it stops.

I had to cut some of my match loads by 1.5 grains to stop primer piercing with the new brass WSR. I could fire 1.5 grains more in the old nickel plated WSR and never have a pierced primer. Ridiculous.
 
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SlamFire1 - what is your opinion of CCI-BR-SR primer? I understand they have a thicker cup, but I don't know if the cup to anvil distance is as long as it is in #41 primer.

If possible, I'd like to use to BR primers, as I don't want to rework my favorite loads for use with the magnum-like #41 primer.

I'm not loading anything hot, so my only goal is to reduce the possibility of pin-induced slam firing. As an added bonus, according to the table posted by WEG, they seem to be the widest of the CCI primers, which is nice, in case some of my brass starts to develop a large primer pocket from use.
Like I said back in Post #23, if you're going to spend the money on BR primers why not just buy the #41 primers? I highly doubt you will need to rework your loads just because of the #41 primers unless you're already bumping up against the pressure limits. (which you said you're not doing) I have been using the CCI NATO primers for a long time now and have never had a problem with either. IMO they are just what semi-auto rifles call for. The BR primers are about 25% + more than the NATO primers so like SlamFire1, BR primers are too expensive for my taste. Even the #41 and #34 primers are a little more expensive but not nearly as bad as the BR primers.

(@Natchez) ------- (@Graf & Sons) ----- (@Midway USA)
CCI-400 = $30/k --- CCI-400 = $28/k ---- CCI-400 = $29/k
CCI-450 = $33/k --- CCI-450 = $30/k ---- CCI-450 = $33k
CCI #41 = $35/k --- CCI #41 = $38/k ---- CCI #41 = $42/k
CCI BR4 = $46/k --- CCI BR4 = $52/k. ---- CCI BR4 = $53/k

All are much cheaper than the CCI #35 primers for the 50 BMG. They run from $150 to $197 for a box of only 500, not 1,000!!!
 
The guy at the local gun shows here has been selling #41s for $5 more per 1K than regular WSR primers. He was at $28 and $33 at the last show. Down from $30 and $35 a couple of months ago.
 
The guy at the local gun shows here has been selling #41s for $5 more per 1K than regular WSR primers. He was at $28 and $33 at the last show. Down from $30 and $35 a couple of months ago.
Now if primer prices would come down to $19.95/k again we will be in good shape! LOL
 
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