Houston we have a problem

[Smokin Joe]

We recently had 2 Kabooms while running our patrol rifle school this past week. Our #1 suspect right now is in sufficient crimps on our reloaded ammo... causing the bullet to fall deeper into the casing prior to being fired. However, you guys are the experts if you guys have any other opinions I'm all ears.

Special circumstances that were revealed after the 2 Kabooms. Prior to the 2 KABOOMS 3 different shooters through out the course of the class discovered 3 different rounds with the bullets seated too deep into the casing. None of these rounds were loaded into rifles. Only 1 individual brought it to an instructors attention. The other 2 figured it was a fluke and dismissed/discarded the rounds when they saw them.

Scenario #1:

Rifle: Personally owned Busmaster XM-15E2 with 14.5 inch barrel and permantely attached mini Y-comp flash suppressor.
- rifle condition: Close to new with less than 500 rounds through the weapon.

Shooter: Typical cop with about a year in patrol. Not a gun guy by any means.

Ammo: Was reloaded using a Dillon multi-stage 650 reloading press. I'm still working on the details as to the powder used. I was told by the guy who reloaded the ammo that the powder is by a reputable manufactor. Additionally that you could not pack enough powder into a casing in order to produce an over powered charge. .... Again I'm still trying to get all the details on it.

Conditions: The rifle had less than 50 rounds through it (on this day) prior to the course of fire that had the KABOOM. While shooting a course of fire using departmentally reloaded ammo. Magazine inserted, shooter was mid way through the course of fire, when KABOOM. The bottom of the magazine blew out and the shooter sustained mild powder burns to his hands (I'm not sure how he was holding the rifle at the time).

Results: Bolt and bolt carrier where stuck into battery, the bottom of the bolt carrier was blown out and hanging by a thread from the bolt carrier. After alot of work we were able to remove the barrel from the upper reciever and discovered the extrator was bent out of shape. Casing exploded rearwards (see photo's)

[Smokin Joe]

Scenario #2

Rifle: Surplus M16A1 deparmentally owned with a 20 inch barrel
-rifle condition:OLD school circa 1960's M16A1 unknown how many rounds have been through it. Venture a guess at ALOT of rounds have gone through it. However it (used to) function fine and held a zero.

Shooter: Was a Marine infantry man but has not shot an AR series rifle in 4-5 years prior to our 3 day rifle school. However he shot well and his weapon manipulation was decent to good (in relation to his peers ability).

Condtions: While shooting the last round of the day using the same above mentioned ammo. Magazine was REMOVED prior to the round being fired. When KABOOM. No injury to the shooter

Results: Bolt carrier is blown out same as the bushmaster. Once the upper barrel was removed from the upper reciever we discovered the same scene we found in the bushmaster (see pics)

I have a ton of other photos and can post on demand I just don't want to kill the bandwith (more than I already am).

Hopefully I haven't left out any other pertnant details...

[Roguish Lawyer]

I have a ton of other photos and can post on demand I just don't want to kill the bandwith (more than I already am).


Excellent -- it is imperative that everyone work to conserve our scarce bandwidth.

[Peregrino]

SJ - Pistol powder is the usual culprit though it's probably ruled out since these were the only two incidents. You neglected to mention if there were signs of a barrel obstruction. A short charge with enough powder to stick the round between the gas port and the end of the barrel might still function the rifle but leave an obstructed bore resulting in catastrophic failure with the next round. Stage 3 of your 650 should have the powder check die in it to detect short charges. All the acceptable .223/5.56 powders I'm familiar with fill the case nearly full, any double charge makes a "mell of a hess". I routinely use compressed charges for my match ammo (kiddies don't try this at home) and haven't had any problems. Quarantine ALL of the ammo from that batch. If you used quality components, a digital scale will spot short charges. Otherwise - burn the lot. (Or make the guy that reloaded them pull the bullets. :p ) My best guess without more info - somebody else may be along shortly with a better idea. I'm glad nobody was seriously injured.

Peregrino

[Smokin Joe]

Sorry there was no "detectable" barrel obstructions prior to the KABOOMS. No light pops or feeding issues in previous rounds fired.

[The Reaper]

Joe:

I have fired hundreds of compressed rounds that I picked up off ranges and have never had a KB with any of them. I do not believe that was the cause of your problem.

My suspicion would be wrong/mixed powder or overcharges.

Personally, I would never use anything that the guy loaded again, would see if his insurance would cover the damaged weapons, and would stick to factory loaded ammo, unless you really like living on the edge for $50 per thousand.

Just my .02, YMMV.

TR

[Smokin Joe]

Joe:

I have fired hundreds of compressed rounds that I picked up off ranges and have never had a KB with any of them. I do not believe that was the cause of your problem.

My suspicion would be wrong/mixed powder or overcharges.

Personally, I would never use anything that the guy loaded again, would see if his insurance would cover the damaged weapons, and would stick to factory loaded ammo, unless you really like living on the edge for $50 per thousand.

Just my .02, YMMV.

TR

Hmmmm that adds new light...

We have seperated the lot of ammo and we are going to be disecting a lot of bullets to see what the issue maybe.

As for replacement weapons goes thats going to be on the departments shoulders. The guy is a Deputy who was given the task of making reloads with department equipment and supplies. So we may have a training issue there.

[Gene Econ]

SJ - Pistol powder is the usual culprit though it's probably ruled out since these were the only two incidents. You neglected to mention if there were signs of a barrel obstruction. A short charge with enough powder to stick the round between the gas port and the end of the barrel might still function the rifle but leave an obstructed bore resulting in catastrophic failure with the next round. Stage 3 of your 650 should have the powder check die in it to detect short charges. All the acceptable .223/5.56 powders I'm familiar with fill the case nearly full, any double charge makes a "mell of a hess". I routinely use compressed charges for my match ammo (kiddies don't try this at home) and haven't had any problems. Quarantine ALL of the ammo from that batch. If you used quality components, a digital scale will spot short charges. Otherwise - burn the lot. (Or make the guy that reloaded them pull the bullets. :p ) My best guess without more info - somebody else may be along shortly with a better idea. I'm glad nobody was seriously injured. Peregrino

Peregrino:

Joe hasn't mentioned the load as of yet. Need to hear the load. Probably not pistol powder as others were shooting the load without mishap.

My opinion? Probably a max load combined with worn out brass and worn out barrels or excessive headspace.

Or the reloader tossed in some 69 or heavier bullets on loads inteded for 55 grain bullets. That 5.56 is not real forgiving in terms of handloading mistakes. The AR-15 isn't a Quad Lock.

For blasting, it is better to buy some American Eagle stuff than to hand load it anyway.

Gene

[Gene Econ]

Sorry there was no "detectable" barrel obstructions prior to the KABOOMS. No light pops or feeding issues in previous rounds fired.


Joe:

Three questions.

1. Why didn't the trainer cease fire after the first blown up rifle?

2. What was the load that the handlader said he was using?

3. What was the real load that was used after pulling about 100 bullets? This includes weighing of each bullet as the fellow may have mixed bullets.

I doubt it was pistol powder or you would have heard multiple booms at the same time as every AR blew up on the first round fired. Pistol powder loaded into a rifle cartridge will either lock the rifle up permanently or blow it to pieces.

I would bet that a bunch of spent cases from the class are missing primers. These spent primers can be found in the trigger well on AR's BTW and they will cause a malfunction of the trigger so it is best that everyone who attended this training have their trigger well carefully inspected for spent primers. A very good look while shaking the lower as small rifle primers can get hidden below the trigger assembly parts.

Gene

[The Reaper]

Okay guys.

Lots of good advice here. I concur with Gene, the bullet weight could also be a factor, a 77gr. projo over a hot 52 gr. load can cause serious problems.

Follow this.

1. Be very cautious when shooting unknown reloads. I will only use reloads from a couple of buddies that I know to be as anal about it as me. Companies that reload have to carry serious liability insurance, for a good reason.

2. Inspect the first few fired cases at the beginning of the shooting session and from each new batch closely. The eye you save may be your own. While visual inspection is not necessarily a good way to detect pressure, popped or blown primers are definitely a sign of trouble, STOP!

3. If a problem occurs, stop shooting immediately, clear all weapons, take note of any observations by all shooters, collect the brass, unfired rounds, and any other evidence.

4. Have an experienced reloader inspect the brass and tear down the rounds, inspecting the cases, powder, and projos. He should have a good scale, or he is not an experienced reloader.

The weapon is an instrument of lethal force. With bad ammo, it can become as dangerous on the shooting end as it is downrange. Be careful and if something seems wrong, STOP SHOOTING and figure it out!

TR

[Smokin Joe]

Gene,

1. I wasn't running the line at the time nor was I on the range so I'm not sure why they let everyone continue shooting.

I do know that there was some ammo mixtures..... ie American Eagle ammo and Reloads got mixed together in guys pockets during magazine reloading.

The other issue is the department has only bought/used 55gr FMJ bullets for reloads, we don't have any lighter or heavier bullets in our entire stock.

I'll start checking for blown primers.

And I'll get the answers to your other questions ASAP.

Thanks Gentlemen for the guidance.

[Psywar1-0]

As for replacement weapons goes thats going to be on the departments shoulders. The guy is a Deputy who was given the task of making reloads with department equipment and supplies. So we may have a training issue there.

Very much so, last time depts loaded their own ammo 1860 Army's were the issue handgun:eek:


I understand the desire to get the mission done, but reloading without formal school training is not something that I would ever do for the Job.

[HOLLiS]

Very much so, last time depts loaded their own ammo 1860 Army's were the issue handgun:eek:


I understand the desire to get the mission done, but reloading without formal school training is not something that I would ever do for the Job.


A close friend is a retired Deputy from a department in California. He was the range officer for that department for almost 10 years and competed often. That department would re-load.

I know other department that use to do that too. Problem, I think you are eluding too, there are reloaders and then there are reloaders that are clueless. Most reloaders I know have decades of experience and also a commonality is not trusting someone else's reloads (unless they know that person).

Progressive presses have their own unique reloading errors. Especially if methodology is broken or interrupted. I really can not offer any other suggestions to what has already been said. I am waiting to find out what happened.

[Karl.Masters]

SJ,

Absolutely concur with all previous comments.

I would recommend that you conduct a check of overall length (OAL) of the rounds in question if it is still possible to do that with rounds from the lot in question.

Shooters able to visually detect an issue with short OAL, and discard the rounds, indicates a potentially large deviation from proper tolerance.

Also, I understand that recovery of the projos involved may be impossible, but I don't know your training devices & range set up. If either projectile could be recovered it could provide some additional clues to the failure mode.

My .02

V/r
Karl

[Smokin Joe]

SJ,

Shooters able to visually detect an issue with short OAL, and discard the rounds, indicates a potentially large deviation from proper tolerance.

V/r
Karl

Sir, when one of the rounds was brought to my attention. I observed it to be sitting about 50%-60% deeper into the casing then it should have been. A theory that is being kicked around right now (pre-ammo lot inspection) is that we may have a crimping problem.

The ammo inspections are now underway.

Both Bushmaster and Colt have been contacted concerning the incident. Both manufacturers have requested we send them their rifle for inspection. They are enroute.

Hopefully, I can get some answers soon.

Everyone,

While inspecting the bolt faces it is obvious that both weapons sustained the same damage. Or mechanism of damage. I.e. both rifles fired while the bolts were in battery. The gun goes "BANG" and at some point the gas thinks it is a better idea to go out the ass end of the casing then to go out of the barrel. The primers get smashed into the firing pin channel, the base of the casing tries to smear its way through the ejector, the extractor gets bent about 30-45 degrees out ripping the side of the lip off. On rifle #1 the base of the magazine gets blow out and on rifle #2 we get severe damage to the dust cover.

Question: WHY?

Let me try and clarify what I'm asking. From the time the primer is struck and the powder goes off what is the sequence of events (from your guys experience)? Does the gas linger in the chamber too long and say "screw this I'm going out the back door"? While doing so does it travel down the side of the bolt and inside the bolt carrier? or between the BCG and the upper reciver? Did all that gas come out of the ass end of the casing? or Did it travel down the gas tube and get hyper-pressurized.. (causing the blow out on the bottom of the bolt carriers)?

I'm trying to grasp what happened inside the chambers and rifles that caused the specific damage. I have been an AR-15, M-16, and M-4 armorer for only 3 months so I'm trying to learn... and this seems like a great problem to get educated on.

Thanks again for all of your guys help and time. I really appreciate it.

[Karl.Masters]

SJ,

I'm going to take a stab at this.

My hypothesis would be that a short OAL round was fired and the projectile was not in contact with the barrel lands and became cocked at an angle in the lands, or was driven into the lands at a slight yaw inducing an edge drag of the projectile gilding metal on the edge of a land.

This situation would cause the projectile to offer more resistance to the gas charge, but only temporarily, as the projectile would eventually deform and clear the barrel.

But the time it takes for the projectile to deform would essentially create a temporary barrel obstruction.

The time it takes for the projectile to deform and overcome resistance induced by this projectile misalignment could cause a dramatic pressure rise in the chamber that could result in the situation you noted.

I recommend a check of the the interior of the chamber in the weapons and look for evidence of jacketing material that may have been stripped/cut off the projectile by the edge of the lands to confirm this as a possible failure mode.

My .02,

Karl

[The Reaper]

Question: WHY?

Let me try and clarify what I'm asking. From the time the primer is struck and the powder goes off what is the sequence of events (from your guys experience)? Does the gas linger in the chamber too long and say "screw this I'm going out the back door"? While doing so does it travel down the side of the bolt and inside the bolt carrier? or between the BCG and the upper reciver? Did all that gas come out of the ass end of the casing? or Did it travel down the gas tube and get hyper-pressurized.. (causing the blow out on the bottom of the bolt carriers)?

I'm trying to grasp what happened inside the chambers and rifles that caused the specific damage. I have been an AR-15, M-16, and M-4 armorer for only 3 months so I'm trying to learn... and this seems like a great problem to get educated on.

Thanks again for all of your guys help and time. I really appreciate it.

Joe:

To understand this, you have to understand the cycle of the weapon fully. Apologies if I get any of the nomenclature wrong or give too much detail.

The AR series rotary bolt lugs lock into the barrel extension during the feed cycle. They do not unlock in the firing cycle until after the gas has impinged into the bolt carrier body and acted on the rear of the bolt, causing the lugs to unlock, and then the following extraction and ejection cycles occur. If the pressure exceeds the capacity of the cartridge case, it will normally perforate or blow out the primer, or if really excessive, blow out through the case after violently unlocking, commonly blowing out in the web just forward of the rim. The "pressurized area" is normally inside the bolt carrier group in the expansion chamber between the bolt rings and the inside of the bolt carrier group. In at least one of your pics, it appears that the bolt never unlocked and the round vented through the primer and case head. When the gas blows out the primer in minor overpressure, I believe that the safety vents are the two holes in the dished part of the bolt carrier that are in the ejection port area, or through the firing pin channel and normally out the bottom of the mag well. It takes extreme overpressure to blow the bolt apart as with your rifle. That is what makes me think pistol powder. Blowing the primer normally occurs before the bolt has unlocked. If the web of the case is blown, it happened after the bolt lugs unlocked. A round that blows way overpressure immediately will frequently shear lugs off the bolt, and/or break the extractor, but that does not appear to have happened in your case. Incidentally, the ejection port door will be closed for all rounds in a string except for the first one, after it has been manually closed.

I agree with Karl that it would be worth it to examine the bore with a borescope if you have not already returned the rifles. You may be able to see where the projo was when the overpressure occurred.

It is paramount though, that reloading be restricted to personnel who you would trust with your life, or for their personal use only. Most manufacturers void warrantees if reloaded ammo is used, and my money is on the reloader having done something stupid. The odds of two rifles failing nearly simultaneously of their own accord are extremely low.

Crimping is a matter of adjusting the bullet seating die (or a crimping die, if you have that station). It is much easier if your bullets have a cannelure to crimp into. The crimp is critical to prevent bullets from jumping the seating in revolvers and to prevent bullet setback in autoloading and mag fed weapons.

Hope that you get it sorted out soon.

TR

[Smokin Joe]

Not to worry TR our reloading program is on hold. Such a hold that someone maybe getting an almost brand new Dillion 650 for a smoking price.

Thank you gentlemen, your responses have shed more light.

[Smokin Joe]

Gentlemen,

Here is the data I was supplied regarding the ammo.


Joe

The load I “said I was using” and the “real” loads are the same: .223, FC (commercial) once-fired cases, Winchester small rifle primers, Winchester 55 gr FMJ bullets, 24.7 gr of Hodgdon Varget, OAL 2.255”, cases not crimped. All loaded on a Dillon Precision 650 with auto case feeder and powder check.

Pulling the rounds I found the following:

Powder ranged from 24.5 – 25.1 gr (Load data shows a range of 25.5 gr – 27.5 gr with a 55 gr bullet.)
Bullets ranged from 54.9 – 55.2 gr
OAL set to 2.255”. A check showed they ranged from 2.240” – 2.260”. Also, found no cases out of spec using a case gage.

No primers were missing from any spent cases.

4. No chance of mixing bullets as the only ones in the building are the Win 55 gr.

5. No chance of mixing powder as the hopper is marked with the powder in it and I’m the only one loading at this point.


What do you Gentlemen think now? Any change in your opinions?

(If I haven't said it before) I don't know jack-sh*t about re-loading so this info is lost on me. I always buy and shoot reliable commercial factory ammunition.

Thanks again for any help.

[The Reaper]

I guess the ammo was perfect and there was nothing wrong with the rounds.

The KBs never happened, and these are not the droids you have been looking for.

One gun might eventually fail catastrophically. The odds of it happening to two different ones at the same time are nearly impossible. I stall say the ammo is to blame.

Personally, I am not sure that I would use the reloader to tear down and check his own ammo, sort of like asking someone to investigate his own crimes.:rolleyes:

TR

[82ndtrooper]

I guess the ammo was perfect and there was nothing wrong with the rounds.

The KBs never happened, and these are not the droids you have been looking for.

One gun might eventually fail catastrophically. The odds of it happening to two different ones at the same time are nearly impossible. I stall say the ammo is to blame.

Personally, I am not sure that I would use the reloader to tear down and check his own ammo, sort of like asking someone to investigate his own crimes.:rolleyes:

TR

It does make it easier to make a case for Bushmaster and Colt to replace their two rifles. :munchin

I cant imagine that Bushmaster has any of their rifles chambered for only .223 Remington and not Mil Spec 5.56. Wylde Chambering.

[Team Sergeant]

Gentlemen,

Here is the data I was supplied regarding the ammo.

What do you Gentlemen think now? Any change in your opinions?

(If I haven't said it before) I don't know jack-sh*t about re-loading so this info is lost on me. I always buy and shoot reliable commercial factory ammunition.

Thanks again for any help.

Who pulled and weighed the bullets, powder etc? The same person that loaded them?

I'm with TR, I'm betting you find out that there was excessive pressure in both rifles caused by improper reloading.

In all my years I've never seen a weapon blow, not from bad ammo. Trust me when I say we put them through hell. I've seen them cook- off, I've seen them break, parts crack, but never a kaboom.

TS

[The Reaper]

It does make it easier to make a case for Bushmaster and Colt to replace their two rifles. :munchin

Not really. If two rifles blew while shooting reloads, even if HP White checked another 1,000 rounds of reloads and verified they were all fine, the manufacturers will say that the two bad reloads caused the KBs.

I would look for a nice way to end the departmental reloading, regardless.

TR

[Smokin Joe]

Who pulled and weighed the bullets, powder etc? The same person that loaded them?

TS

For a random sample of the suspect bullets yes, it was the same guy. We are having another individual test another sample of the same reloads.

I should note that it is everyone's opinion (even the guy who first loaded the ammo) that it was an ammo issue in the first place. Not a weapon issue.
No one is trying to lay the blame on Colt or Bushmaster (I work for a VERY ethical department that will not tolerate ANY ethical indecression).

We as a department are trying to learn what or how it occured so we do not repeat our mistakes.

I wish we had the ability to cut the barrels and or inspect the barrels and chambers with a bore scope but we just don't have that equipment so we are going to send the rifles back.

TR, Gene, LTC Masters, and TS I really appericate the insight, the no BS assessment, and the time all of you Gentlemen took to reply.

I'll update you all again when I get the official info back from Colt and Bushmaster.

[Smokin Joe]

I would look for a nice way to end the departmental reloading, regardless.

TR

I agree, I think it is WAY too much liability for the department to absorb. What little money we saved on reloading we just blew on 2 new rifles. What happens if some guy lost an eye or got hurt? The department would be SCREWED!!! well not really but every home owner in my Counties property tax would go up to off set the huge settlement the department would be paying out.

IMHO it is not worth the sweat.

Just my .02 cents

[HOLLiS]

Joe,


If a AR does not go completely in battery will the hammer still cause the round to fire? A case that is not correctly resized could keep a bolt from going to battery..

I have been playing with spent rounds, recently, to see how well they chamber in other rifles. Resizing reduces the cases to min. size, so it will fit in any chamber. A lot of reloader will only neck size for a case to be used in a specific rifle. It extends case life and maybe some other benefits. The idea is the case is matched to the chamber of that particular rifle. I have found a lot of spent cases will fit other rifles without full length resizing.

[The Reaper]

If a AR does not go completely in battery will the hammer still cause the round to fire? A case that is not correctly resized could keep a bolt from going to battery..

Negative, unless the bolt is fully locked, there is not enough firing pin length to reach the primer. Designed to prevent that.

While you could theoretically break the firing pin and have the nose jam in the forward position, the odds of two guns doing that at exactly the same time are extremely remote.

TR

[HOLLiS]

I agree that would not cause a failure on a normal length round. A elongated cartridge would create a situation where the bolt face, the head of the case would be at zero difference and causing the bolt not to go into complete battery. If the hammer struck the firing pin, it could be sufficient to cause ignition.

On chambering the round the bolt face ceases to move forward and rotates to lock it into battery(Bolt assy still moving forwards until complete battery). If a case is extended rotation may not be possible or a partial rotation might happen. I'll have to check my AR to see if a ignition is possible on a partial or zero rotation of the bolt. This may take a few days.

Kind of like excessive head space, but caused by the case not the firearm.

[Gene Econ]

I agree that would not cause a failure on a normal length round. A elongated cartridge would create a situation where the bolt face, the head of the case would be at zero difference and causing the bolt not to go into complete battery. If the hammer struck the firing pin, it could be sufficient to cause ignition. On chambering the round the bolt face ceases to move forward and rotates to lock it into battery(Bolt assy still moving forwards until complete battery). If a case is extended rotation may not be possible or a partial rotation might happen. I'll have to check my AR to see if a ignition is possible on a partial or zero rotation of the bolt. This may take a few days.
Kind of like excessive head space, but caused by the case not the firearm.

Hollis:

Look at the pictures again and note the bottom of each bolt carrier got blown out. In other words, a huge amount of pressure came back into the bolt and the only way that much pressure could blow the bottom of the bolt carrier apart is if it came down the gas tube and into the bolt as in normal operation. I doubt an out of battery firing would blow the bottom out of a bolt carrier. Not enough gas could get into the bolt with an out of battery firing.

They were using once fired FEDERAL commercial brass! He, he, he. That stuff was a one shot deal with the Federal Match .308 loads. If anyone tried to reload that stuff in .308, they would blow a primer as a minimum if not get a headspace separation. However, they would not blow out the bottom of a bolt carrier. I would however question the sanity of someone reloading once fired commercial Federal brass.

Someone needs to check and see if this reloader had any other type of powder stored in his reloading area. Those two rifles blew up because the powder was way too fast. I would say the fellow either accidentally used some powder like 4198 or that he accidentally mixed powders together while handling the same.

Well, I am sure that the two gun companies will say "handloads too hot". Does anyone think they will say "we used poorly made parts"? Say 'handload' and every gun company in the world will say "handloads were poorly made".

Am still curious as to why the range officer didn't cease firing when the first rifle blew. That one leads me to question the competency of the outfit in question.

Gene

[HOLLiS]

Gene, Not being able to wander through the shop and pick up stuff makes it harder for me.

I thought about powder, It could be possible he ran out of powder before he ran out of cases and refilled the powder measure with a pistol powder. Depending on how many empty cases he had left, that could be why the defective rounds were very low in number.

I have been using a progressive (dillon 500B) for over 14 years. I try to think of what type of error could happen. Due to the powder capacity of the case, I don't think a double charge is very probable. Normal type of error would be squip load, inverted primer, primer not seated properly, no primer. Errors in case seating or crimp, I don't think would cause this failure.

I'll look at those pictures again, but I really would like to have parts in hand.

Being a reloader, I would not want to make what mistake was made. Also I really like Dillon stuff.

Best,

Hollis

[Gene Econ]

I thought about powder, It could be possible he ran out of powder before he ran out of cases and refilled the powder measure with a pistol powder. Depending on how many empty cases he had left, that could be why the defective rounds were very low in number. I'll look at those pictures again, but I really would like to have parts in hand. Hollis

Hollis:

Yes -- look at how the bottom of the bolt carriers were blown out. Given the bottoms blown out of each bolt -- could this have happened from an out of battery firing? I can't see how that much gas could get into the bolt carrier unless it went through the gas system itself.

Your opinion?

Gene

[Smokin Joe]

Am still curious as to why the range officer didn't cease firing when the first rifle blew. That one leads me to question the competency of the outfit in question.

Gene

As I understand it now firing was stopped. Everyone ooh'd and aaah'd over the first Kaboom. But it was dismissed as a freak accident, which has never happened to us in the past so the thinking from the guys on the range at the time was "that our luck ran out and we had our freak accident".

However when number 2 went; all training ammo was pulled from the range and only issued duty ammo was shot.

[The Reaper]

The blown out gas cylinders and destroyed case heads indicate to me that Gene is exactly on track. Way too much gas under far too much pressure got into the system all at once, and could not get out before the bullet movement out of the barrel or the unlocking of the bolt relieved the pressure. Remember that the bullet had to make it past the gas port for the gas to reach the gas cylinder area of the bolt.

I have seen revolvers do this and KB with extremely light loads. The theory was that the powder exploded rather than burned. I do not think this is the case here.

IMHO, heavy bullets or weak cases would not produce the severe destruction that you have with these weapons.

So, we are back to the powder.

What is the case capacity of the Federal .223?
What degree of fill would the claimed load produce?
How much Varget can you fit into the Federal cases?
What other powders are present in the reloading area? Especially pistol reloading powder.
Who has access to the reloading area?

TR

[HOLLiS]

Gene,

The case looks like it failed at the head. From old reading, so it may not be very correct anymore, at the High pressures ignition the brass become plastic in characteristic and flows. The higher the pressure the more molten it becomes. When pressure is relieved it goes back to the normal characteristic of brass. This allows the case to create a gas seal with the chamber.

Improper head spacing, does not allow for the case to be adequately supported. The case looks as though it blew out from the base. I think we can obviously say, excessive pressures, but why?

In the M4 full auto config and in full auto mode (same with AKs) When the bolt goes to battery it trips the hammer release. In semi auto this does not happen. Normally a person cannot release the trigger and fire again in the time it takes the bolt to complete the cycle. Semi auto Uzis has a firing pin catch that prevents the firing pin from firing, unless the bolt is in battery. (prevents slam fires and full auto mode).

A guy asked me about bump firing a AK. I told him, "I would not recommend it." for the reason stated above.

Now look at the roll the extractor has, on stripping the round from the magazine, the head of the round is matched to the bolt face and locks into the extractor. Also the case is being aligned with the chamber. I am not sure, if the holding of the case by the extractor would be sufficient to allow enough pressure from the firing pin to ignite the primer when the bolt is not completely in battery.

I would, maybe, suggest on the remaining ammo, check them with a case gauge if it is possible. It still may not show any unusual problems for the reason I mention below.

The other problem with once fired brass, It may been reloaded once already. Picking up range brass does not always insure the same brass is being picked up, a few remnants for a previous shoot may have been left behind. Those two cases could have been reloaded previously, maybe one of those loaders who uses max load plus 20%, the cases could been faulty to begin with. Remember case separation in the old 303 Brits. I would think head separation would have happened in that was the situation.

Did Joe measure the the case length that ruptured?

On the gas system, I don't think it was involved. The gas tube would have probably ruptured with that amount of pressue.

Best,

Hollis

I am building a receiver today, I will play around with my AR and some "dummies" to see what I can determine when I take a break.

[HOLLiS]

Gene,

I am playing with a bolt on a AR, I think TR understanding is much better than mine. The firing pin needs the bolt to be Almost completely rotated to be long enough to touch the primer.

Hollis.

[Gene Econ]

However when number 2 went; all training ammo was pulled from the range and only issued duty ammo was shot.

Joe:

Has anyone come to any conclusions abpit these rifles yet?

Thank you

Gene

[Smokin Joe]

Joe:

Has anyone come to any conclusions abpit these rifles yet?

Thank you

Gene

Gene,

Not yet.... Feet are dragging at this point. Our independent reloader is supposed to come in next week to test some more bullets. I guess with all of our upcoming biker rally's this has been put on a slow burner and I'm not in a position to light any fires. :o

I will up date you when I know something.

Joe

[Smokin Joe]

We recieved the Bushmaster back a few days ago.

Bushmaster didn't really say much other than "here you go" They replaced the Bolt, Bolt Carrier Group, charging handle, lower reciever and barrel.

We are currently trying to get a hold of them to see if they were able to find the cause but I'm getting the felling that they didn't investigate the issue they just fixed the rifle and moved on.

Either way kudos to them for there customer service.

[The Reaper]

Well that is a decent thing to do.

Kudos to BM. Wonder what Colt will do?:munchin

TR

[82ndtrooper]

Well that is a decent thing to do.

Kudos to BM. Wonder what Colt will do?:munchin

TR

Colt ?? You mean people still purchase those ? :rolleyes: