View Full Version : Had a kaboom with my reloads.
I reload for my cheaper ARs which is a good thing in this case. Anyway I'm not sure what happened here. I'm going to blame myself till I'm told otherwise. This is the case, the barrel is still good, bolt still good. The bolt carrier is blown as well as the upper and extractor is bent. I'm thinking I missed a cracked case. I was using 55gr FMJ boat tail and 23gr of AR Comp. The case looks like it was fired out of battery as well. Thoug that would not explain the carrier being blown out. https://uploads.tapatalk-cdn.com/20191203/aee1f5e6687e61c79c81cf856c2c6a2e.jpghttps://uploads.tapatalk-cdn.com/20191203/eaf62c2290869dfc683262cb992536d6.jpghttps://uploads.tapatalk-cdn.com/20191203/f02b99782f69fba434b9e98bacf09caa.jpghttps://uploads.tapatalk-cdn.com/20191203/5bbaf33e2808db1ed7a81bbfd3c3dedb.jpghttps://uploads.tapatalk-cdn.com/20191203/847f97c8af9ab72963e2366f711dfe34.jpg
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The way the extractor is bent might prove that it fired out of battery. https://uploads.tapatalk-cdn.com/20191203/ad9340a9521590afa06f0e01f3f96dfd.jpg
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CAMagnussen
12-03-19, 16:42
I've seen enough "kabooms" with reloads to know I have no interest in them. Good luck. Glad you were not killed, blinded, or otherwise. Is it really worth your while to reload 5.56 cartridges?
That looks like an out of battery to me, do you resize with a small base die?
I've seen enough "kabooms" with reloads to know I have no interest in them. Good luck. Glad you were not killed, blinded, or otherwise. Is it really worth your while to reload 5.56 cartridges?I get you your point very well. After at least 8 years one finally got me. I wasn't hurt, got a bit of a superficial burn on my finger. This happened in June, I just now decided to take the upper apart to see if anything was salvageable.
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That looks like an out of battery to me, do you resize with a small base die?I was using Lee 223 dies.
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Most of the "grey beards" around here say it's impossible for an AR to fire out of battery.
A simple case web failure seems plausible here.
All that pressure released out the wrong end will bend the extractor, peel the carrier open like a banana and blow the magazine guts out the bottom.
Most of the "grey beards" around here say it's impossible for an AR to fire out of battery.
A simple case web failure seems plausible here.
All that pressure released out the wrong end will bend the extractor, peel the carrier open like a banana and blow the magazine guts out the bottom.Yeah, I believe you're right, I overlooked a bad case. Just a cheap AR, most of it's salvageable. No hospital visit, the big plus.
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I reload for my cheaper ARs which is a good thing in this case. Anyway I'm not sure what happened here. I'm going to blame myself till I'm told otherwise. This is the case, the barrel is still good, bolt still good. The bolt carrier is blown as well as the upper and extractor is bent. I'm thinking I missed a cracked case. I was using 55gr FMJ boat tail and 23gr of AR Comp. The case looks like it was fired out of battery as well. Thoug that would not explain the carrier being blown out.
I wouldn't assume that bolt is still good.
They're cheap enough it would go in the trash and I'd buy another. Heck, I'd be tempted to trash the barrel too.
Ned Christiansen
12-04-19, 00:18
Did you trim cases to length? Firing out of battery by means of dropping the hammer, not an optional explanation. To me it's untrimmed cases, bore obstruction (like last round was a "click" and got manually racked out) or an issue with the powder charge / bullet weight and possible contributor, .223 chamber-not-5.56.
Firing out of battery by means of dropping the hammer, not an optional explanation...
Is it possible that a stuck firing pin did this, in combination with not fully chambering?
The back of the case looks like it wasn't supported when the cartridge fired...
Is it possible that a stuck firing pin did this, in combination with not fully chambering?
The back of the case looks like it wasn't supported when the cartridge fired...
In the ARFOW, the firing pin is positively retracted when the bolt is unlocked.
The firing pin is only "unblocked" after the bolt has been rotated into the locked position.
That bell shape in the brass could be due to an out of spec chamber feed mouth / feed cone not supporting the brass well.
This is a likely culprit in a "cheap" AR barrel.
In the ARFOW, the firing pin is positively retracted when the bolt is unlocked...
Oh, yeah... I guess I was thinking M14.
That bell shape in the brass could be due to an out of spec chamber feed mouth / feed cone not supporting the brass well.
So radical over-pressure and an out-of-spec chamber?
Ned Christiansen
12-04-19, 11:21
The cartridge was fully chambered. They always look like they were "sticking out" a bit but what we see here is the brass having flowed into the chamfer/radius at the chamber entry at the rear face of the barrel, and into the chamfer where the bolt face recess meets the bolt face.
They always look like they were "sticking out" a bit but what we see here is the brass having flowed into the chamfer/radius at the chamber entry at the rear face of the barrel, and into the chamfer where the bolt face recess meets the bolt face.
So this is just a case of waaay too much pressure?
Ned Christiansen
12-04-19, 11:54
My opinion, yes. We just don't know why.... apologies to the OP but being handloads generally opens up a lot of possibilities. Not impugning your abilities as a reloader OP, things can happen under the best of conditions, and as we sometimes see, at the ammo factory too.
My opinion, yes. We just don't know why.... apologies to the OP but being handloads generally opens up a lot of possibilities. Not impugning your abilities as a reloader OP, things can happen under the best of conditions, and as we sometimes see, at the ammo factory too.Could it be from AR Comp temp sensitive? As I stated it was in June and on a hot day at that. The ammo was in the trunk of the car. I was using metal 20 round mags, they were warm, then setting in the sun made them heat up more, while I was setting things up.
For what it's worth I do trim cases, check OAL and also shake to hear powder.
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MagpulBuff
12-04-19, 20:59
Good that it didn't all go south!
Out of battery is nearly impossible. Even if debris ignited the primer, the force of the bolt closing would be needed to create the impact needed.
A bad case is unlikely or it would have probably failed on the original firing of the factory load, but again... maybe.
Most likely is an over charge. I don't know much about AR comp, but a ball powder with only 23 gr leaves A LOT of case volume available for an over charge.
And as far a reloads, Good ones run rings around factory ammo, and are much more trustworthy and predictable. I wouldn't run factory through a suppressor or a machine gun.
scottcc,
First......do you use mixed manufacturer brass (?)……...and do you process all of this at the same time or separate into "lots" to be processed/loaded as "lots" (?).
Do you trim for case OAL after resizing or before (?).
During your re-loading phase...…...do you check "neck-tension" of the bullet being held by the case (after seating) (?).
Do you use bullets with or without "cannelure" (?)…...and do you use a form of tapper-crimp or "factory-crimp" on the projectiles (?).
After looking at your case photos...….what I am seeing (due to the flow of the brass) is "over-pressure" due most likely to bullet "set-back" during chambering. This bullet set-back would make your chamber-pressure increase dramatically.
Some possible causes:
1: Sizing after trimming cases for length. This gives you different length cases "and" will effect neck tension.
2: Use of cartridge-cases with different OAL.....again, effects neck-tension.
3: Using a case with a "split-neck" missed during case-inspection....again, loss of neck-tension.
4: Use of mixed weight bullets during loading of the same powder-charge.
5: .......….or this could be as simple as your cartridge didn't chamber at first try (bullet hitting breach-face and set-back into case)......you pull the charging-handle back slightly where the cartridge is allowed to chamber without being inspected...…….and then fired/"BOOOOOM".
What also helps some re-loaders stop bullet set-back is the use of bullets with a cannelure to allow the use of a factory-crimping-die.
…..or finding a way to insure that each bullet is seated/crimped at the case-mouth of the cartridge so that it can't move during chambering.
Regards, RichardS
US Army, RET
After looking at your case photos...….what I am seeing (due to the flow of the brass) is "over-pressure" due most likely to bullet "set-back" during chambering. This bullet set-back would make your chamber-pressure increase dramatically.
I've found this not to be as significant of an issue as I had previously thought.
When I first tried loading 77 gr Sierra TMKs, I loaded to small batches of OTMs and TMKs to compare. Both had identical charges. The TMKs have a much different ogive and required the bullet to be set much farther into the case than the OTMs to achieve the same over all length. When we chrono'd the loads, they shot the same velocity.
Now if the round was really deformed with the bullet mangled somehow, yet still able to chamber... perhaps it could be the cause. But a 55 gr fmj set back simple doesn't take up anywhere near the case volume that a 77 gr does at correct over all length.
And then of course with more "jump" to the lands, you get more initial bleed of, and thus LESS pressure spike. I just don't see set back as a realistic cause of this.
Were the cases measured to make sure they did not exceed maximum length? Were they trimmed prior to reloading? How much crimp do you adjust your dies for, .002", .003"? If the case length is excessive, the amount of crimp can increase when the bolt goes into full battery and the case mouth is forced into the chamber.
Some will disagree, but I believe the hammer will drive a bolt into full battery if the bolt is open a few thousandths of an inch due to lack of full length sizing or excessive case length. With the bolt in full battery, I've had case head separation on well worn brass when shooting match loads through a lightly used barrel and did not experience an overpressure failure like you experienced.
There is no indication of minimum recommended charge weight on the Alliant website. How did you decide on 23.0g of AR Comp? I've never used AR Comp and have no experience with it.
If the hammer drives the bolt forward, isn't the bolt then properly locked as needed to let the bolt carrier sit close enough the firing pin can reach the primer? Asking honestly.
Case trim length is another thing I've found NOT to be a big issue. Black Hills old Remanufactured 55 gr ammo used to have massively over-length brass. And people shot that stuff by the 10s of thousands of rounds and swore by it.
If the hammer drives the bolt forward, isn't the bolt then properly locked as needed to let the bolt carrier sit close enough the firing pin can reach the primer? Asking honestly.
Yes. Out of battery notion is waste of discussion. Not the cause. (as Mk18pilot pointed out a few years back... without the bolt locked, you don't achieve the over 65,000 psi or whatever needed to burst the case head)
There is no indication of minimum recommended charge weight on the Alliant website. How did you decide on 23.0g of AR Comp? I've never used AR Comp and have no experience with it.
Not the OP, but...
On the website, right before you enter the guide:
REDUCE RIFLE AND HANDGUN CHARGE WEIGHTS BY 10% TO ESTABLISH A STARTING LOAD
My math gives me 23.04 gr for a starting load.
Not the OP, but...
On the website, right before you enter the guide:
REDUCE RIFLE AND HANDGUN CHARGE WEIGHTS BY 10% TO ESTABLISH A STARTING LOAD
My math gives me 23.04 gr for a starting load.
Valid point. I like to see data that displays the recommended minimum charge weight in grains. I have been on the telephone with Hodgdon a few times and was told that listed minimum charge weights were actually tested.
Case trim length is another thing I've found NOT to be a big issue. Black Hills old Remanufactured 55 gr ammo used to have massively over-length brass. And people shot that stuff by the 10s of thousands of rounds and swore by it.
I was not aware that Black Hills brass was overlength; thanks for the information. I have not measured .223 brass on a loaded cartridge, then fired ammunition with overlength brass out of a rifle. I have seen what out of spec brass will do to a M1 Carbine. The M1 Carbine brass was on ammunition that I culled out of new factory ammunition and was over maximum length by .002" - .004". Another shooter on the firing line did not think it was an issue and asked to fire it. I should not have given him the ammunition. During the slow fire prone stage he blew up his Quality Hardware carbine and I was hit with a piece of the stock. I know the chamber was within service limits, because I watched him check with Go and No Go gauges when he bought the carbine several weeks before the incident. The bolt did not go into full battery on the No Go gauge.
When it comes to overlength brass on bottle neck cartridges, I defer to the Hornady Handbook of Cartridge Reloading, Fourth Edition, Vol. 1, page 11. Hornady cautions against reloading overlength brass, due to overpressure concerns. On a service rifle with a generous cut on the leade, or worn throat, it is less likely to happen, but still possible.
One thing I know for certain is that I can't be certain what will happen if I don't trim or full length size brass when reloading for a semi-automatic rifle.
I've seen enough "kabooms" with reloads to know I have no interest in them. Good luck. Glad you were not killed, blinded, or otherwise. Is it really worth your while to reload 5.56 cartridges?
I’ve seen enough kabooms with factory ammo to know I have no interest in them.
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I think I know where I errored. I must have loaded 5.56 cases using 223 load data. It still should be under max, but a 556 barrel, hot day and maybe factor in bullet set back.
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When it comes to overlength brass on bottle neck cartridges, I defer to the Hornady Handbook of Cartridge Reloading, Fourth Edition, Vol. 1, page 11. Hornady cautions against reloading overlength brass, due to overpressure concerns. On a service rifle with a generous cut on the leade, or worn throat, it is less likely to happen, but still possible.
I makes sense that it would be problematic, although I've never seen it happen.
I think I know where I errored. I must have loaded 5.56 cases using 223 load data.
The brass is the same. Some .223 brass will give a velocity boost, but not enough to kaboom on you.
You had a case head failure. That's it. It happens. What is shown is the unsupported case head that let go.
Several things come to mind here.
Using a depth mic measure from the back of the barrel extension to the back of the barrel on this and other factory barrels. This would not be the first time a barrel was chambered to where the headspace is correct but as pointed out the back of the case is unsupported.
Such will also happen if you pick up a case that has been in a fire and the head is soft.
Or it could have gone through the loading line annealing upside down.
If the barrel had water in it you will get similar.
I used to do M16A1 catastrophic failure investigations when I worked for the Army Small Cal Lab and worst I ever saw bowed the upper receiver out to where it was 2" with and the lower receiver the same way. The mag was inserted into the shooter's forearm.
I would like to see a pic of the back of the case and close up of the primer.
Was this a small rifle primer or was it a milspec primer you loaded?
You can also get a unlocked bolt ignition from a overheated weapon where the gas tube gets flexible due to heat, moves out of alignment and stops the bolt closing on a partially chambered round and if barrel temp is about 400 deg F it will likely cook off in about 8 to 10 seconds and can be particularly nasty.
I estimate the pressure on this case was about 90,000 lbs which can occur from several factors.
A section of cleaning rod left in the barrel will to it as well.
Is a delayed cook off possible? I've had two in 9mm before, both with factory Winchester White Box. I was lucky to just get sprayed with mostly unburned powder.
Not sure what your definition of "delayed cook off entails"
We did cook off tests on M16s which consist of 500 single shots in 500 seconds and start a stop watch when the 501st round is chambered and it takes 8 to 10 seconds for them to cook off.
The rule of thumb in testing in machineguns is if you get a stoppage you have 5 SECONDs to open the bolt which means you don't sit there and scratch your head and ask Bubba to ask Jethro what they think and get a consensus of what to do. If bolt is not opened the temp rises and if if bolt it locked and goes off no problem.
If you are right in the middle of opening the bolt giving the barrel time to heat the round you are asking for a problem.
We had a gunner and a loader killed in Alaska who opened the bolt on a failure to fire and we got word it happened and they were both unconscious in ICU. The Chief of the Small Cal Lab asked if the local commander wanted on site accident investigation as he was ready to put three of us on a plane and the plan was one guy would sit between their beds 24 hours a day hoping one would wake up and the first question to be asked was did you open a bolt on a misfire?
As it turned out the local commander talked to his local attorney who advised him not to ask for investigation as it was going to look bad on his career so he declined. A couple days later one died and the Commander got nervous and asked for investigation and he was told he had obstructed an investigation and thus he had the ball so to speak. Several days later the other one died.
Bottom line was OPEN within 5 seconds and if you don't then don't touch it for 30 minutes. This is drilled into professional gunners and there are signs on the ranges telling all that and yet we still had a gunner open a bolt about 10 seconds into a stoppage and he got brass fragments in his face/hand/arm.
I worked with a guy who was a M60 gunner in Nam and they had human waves hit them and he had hooked a sea bag full of belts together together and Charlies were in the wire and they sat down on final defense matrix and the barrel went white hot and when they stopped the gun kept firing about one round every few seconds and his Sergeant just reached up and broke the belt and let it shoot them out.
I relayed that story to the M60 engineer in charge and he said that must have been a very good barrel as they generally blow out the side of the barrel a on the way out the muzzle when it gets thinner before they go to white hot or the bolt lugs dig into the barrel socket and won't open at all.
We had armor suits designed for such testing with every inch of the gunner is protected and the object is to run it till it blows and the M16 tends to partially chamber as the bolt does not close.
It is easy to tell if you have a cook off as there will be no striker indent on the primer and the center of the primer reverse blows into striker opening on bolt face and you will likely find a piece of the primer inside the bolt.
Much the same thing can happen on a M16 with insufficient striker energy which means the striker does not have enough energy to hold the primer indent forward long enough for the pressure to back down and it craters around the edge. This is one of the reasons the MILSPEC primer cups are heavier which also means you have to whack hell out of the primer to get it to fire.
In the gov't small arms the hardest primer to fire is Cal 50 BMG, the second hardest is the primer for 5.56 and it goes down to where the easiest primer to fire is on 38 Special Wad Cutter ammo.
I bought a Rem 7615 about ten years back and it was reverse flowing described above with MILSPEC ammo as I have the equipment to conduct striker energy testing to see if it is in spec so I called Wolff Springs and ordered a new hammer spring and checked the spring energy and it was in spec and the same ammo stopped reverse flowing immediately.
If you load standard small rifle primers in 5.56 ammo you will likely get a punched primer as the cups are too thin to hold up to the higher pressures. You read tons of opinions about the pressure will blow the guns up but nobody has every proved the THEORY. I had a buddy at Winchester and he said they had plenty of blanked primers but nobody ever reported a blown commercial rifle as is the warning you always read.
When the black rifles got into competition there were lots of pierced primers and I wrote a number of posts explaining it and when folks put the right primers in the problem went away.
So a cook off is not necessarily a bad thing, stupidity is.
For instance we got rifles in where guys downloaded blank propellant from several rounds and put it in one case and shot it and even though there was no bullet the case let go.
When we got a rifle in for investigation and there was no case included and the rifle checked out dimensionally and metallurgically that only leads to our thinking WHY DIDN'T THEY INCLUDE THE CASE?
I never saw a catastrophic failure on a M16 barrel with a round coming out the side of the barrel but I can tell you we had a M14 cook off test and on the 14th mag of continuous full auto at round 276 a round exited the barrel about half way to the gas port.
I had a buddy in SF in a fight in Nam catch a M1 Garand stock on fire but barrel held.
When I left the gov't we had never had a case of a action failure on anything from the 1903 Springfield onward.
Just remembered saw a pile of 98 Mausers that were all fired with cleaning rods in barrel and not one action had lug shear.
A guy tried to sue the government saying the Springfield was a bad design. He converted one to 308 Norma Magnum, loaded the rounds with a 30% overload, heated the front of the action with a torch so he could mount scope mount, heated the rear ring same way to mount a scope and then decided he wanted a Griffin & Howe mount and heated the whole side of the receiver so he could drill it. Then he mounted the scope.
My buddy was the gov't expert witness and the lawyer for the plaintiff asked his name, occupation etc and then he screwed up. He asked him to outline the development of the 1903 and my buddy asked if he wanted a brief overview or in depth survey and lawyer said a brief overview was fine and my buddy quit talking and had 456 pages of typed pages of testimony. Lawyer had no more questions. Jury was out 15 minutes and was back and ruled the would be gunsmith was stupid above and beyond the call of ignorance and that ended his lawsuit.
My buddy said the bolt came out the back of the rifle and caved his face in and really looked bad. My buddy and taken a 03 and chambered it and loaded it with same load the guy used and ran a thousand rounds through it and the action held fine. Moral to this story is just because you have a acetylene torch doesn't mean you know what you are going.
Also aware of handloaders who put primer in and missed putting powder in and launched a bullet about an inch or so down bore and put a loaded one behind it. Now that will mess things ups.
Oh by the way when barrels fail they tend to fail at 9:00 or 3:00 for some reasons. Very few have seen a 6 to 12 oclock failure and I have not and never talked to a guy that did.
CIP a guy at Trinidad Gunsmith school class in about 1950 and they were told by PO ACKLEY to never re-chamber a gov't barrel for a magnum round and one of the students chambered a 1917 Enfield in 300 Win Mag and barrel failed shearing off four fingers on his left hand. As a side not P14 barrels and known to start splitting at the muzzle and work their way back towards the action. They are also know to have been improperly forged on the third shift at Eddystone.
That is only known because another buddy knew the 3rd shift plant manager at Eddystone who continually caught guys not forging correctly or at the right temperature. My buddy rented a room from him 35 years later and he passed that tidbit to him and he passed it to me as he was the one that trained me at the Army Small Cal Lab. The guy that trained me was a treasure trove of info and had a memory that would impress any computer designer.
Several things come to mind here.
Using a depth mic measure from the back of the barrel extension to the back of the barrel on this and other factory barrels. This would not be the first time a barrel was chambered to where the headspace is correct but as pointed out the back of the case is unsupported.
Such will also happen if you pick up a case that has been in a fire and the head is soft.
Or it could have gone through the loading line annealing upside down.
If the barrel had water in it you will get similar.
I used to do M16A1 catastrophic failure investigations when I worked for the Army Small Cal Lab and worst I ever saw bowed the upper receiver out to where it was 2" with and the lower receiver the same way. The mag was inserted into the shooter's forearm.
I would like to see a pic of the back of the case and close up of the primer.
Was this a small rifle primer or was it a milspec primer you loaded?
You can also get a unlocked bolt ignition from a overheated weapon where the gas tube gets flexible due to heat, moves out of alignment and stops the bolt closing on a partially chambered round and if barrel temp is about 400 deg F it will likely cook off in about 8 to 10 seconds and can be particularly nasty.
I estimate the pressure on this case was about 90,000 lbs which can occur from several factors.
A section of cleaning rod left in the barrel will to it as well.90,000 PSI would have likely destroyed the lower receiver, ? Not much damage to the lower maybe .5mm bowed on the right side of the magwell. I already tried another upper on it and it works fine. I only shot 1, 20 round mag before the failure. All of them reloads from the same batch. No sign of overpressure, until about halfway thru the 2nd mag, which had the round that blew out. There was no difference in sound or recoil that I could notice. Just a burn line on my pinky close to the magwell, and the gun stopped working.
I threw the whole batch out afterwards. According to Hornady's newest manual and Alliant's data, 23gr of ARComp should have been well below the max load. The primer is very flat and the case head lettering is flattened too.
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At about 110,000 the case will start to get liquid, Plastic deformation gets going around 70,000. I was at the Ruger plant and they had 55 gal drums of 70,000 lb proof cartridges that had been fired and they all showed plastic deformation but not to the degree those pics show. Now a case getting heated too hot(like a fire) will do it even with normal loads. There are some ranges folks throw brass into cans with trash and the trash gets lit, cases go soft, somebody retrieves the cases and tumbles them in stainless steel media there is no way to tell unless the hardness of the case was checked.
The primer backing out of the case looks suspicious which tells me the back of the barrel wasn't where it was supposed to be? Another outfit made target rifles and a barrel maker friend tipped me off that there was too much unsupported case head even though it was headspaced to gage and a number of those rifles had web failures.
That lead to the manufacturer buys several hundred thousand cases with extremely thick heads so the high pressure area was supported. Then again you could have had a case with a thin head that exposed the high pressure area to air instead of supported by steel.
I have also heard of folks getting a bigger caliber bullet in a box of smaller caliber bullets and pressures go out the roof which can go in some chambers as there is lots of room in military spec chambers.
The Sierra rep told me about such happening there about 30 years ago and then they started numbering the bullet boxes with lot number and employees could be identified that packed that lot.
I was at a match in NY state once and this guy was shooting M80 ball ammo in a M1A and all of a sudden a tracer goes down range, then another. The guys ammo was checked and there were no red tips in the ammo and then he had another tracer which meant someone at ammo plant had taken a handful of tracer bullets out of production before the tips were painted red and dumped them in a ball bullet hopper and they got loaded. I told the ammo engineers at Picatinny what happened and they said the tracer line was no where near the ball line and somebody was getting cute was the only thing they could figure as all his empties had the same head data on them.
In the pics the top row center pic shows the primer had backed out about .015 or so thus my conclusion the back of the barrel wasn't where it was supposed to be.
Guy at gun plants are not shooters and to them it is a job, not a passion like it is to us. CIP I was walking around Colt plant and this one guy was making a part and I recognized what he was making and I asked him what it did in a AR and he had no clue. The guy that trained me told me that he had seen similar at Rock Island Arsenal as folks get jobs there to keep money coming in during the winter and their main passion is farming. That is why there are gages made up for everything to bubba proof the final product.
Rock Island got a load of M14 barrels in and they were running first article acceptance and three out of a hundred barrels Rockwelled too soft. An analysis was run and they turned out not to be 4140 but cold rolled steel. The investigation revealed a couple guys in plant wanted barrels for their M1A so they switched out round stock on the rack with cold rolled blanks thinking no one would know the difference.
Then I saw M1911A1 slide come in that was certified to have been proof fired and was so stamped but it never had the firing pin channel drilled so how was it fired? It wasn't but it got stamped and certified as having done so.
Is a delayed cook off possible? I've had two in 9mm before, both with factory Winchester White Box. I was lucky to just get sprayed with mostly unburned powder.
I've read of this with people trying to get sub sonic loads with reduced loads on standard powders. (I forget what it's called, but I've never seen any solid evidence of it being a real thing)
Simple delayed ignition won't cause it. I used to get that problem with WOLF primers and certain ball powders. It was the weirdest feeling when the ignition lagged a split second. Never cause pressure issues though.
yes such is possible if you load BELOW THE PUBLISHED MINIMUM IN THE LOADING MANUALS. Won't happen every round but is far more likely to give you a pressure spike.
yes such is possible if you load BELOW THE PUBLISHED MINIMUM IN THE LOADING MANUALS. Won't happen every round but is far more likely to give you a pressure spike.Hmm? It does seem possible the bolt was cycling before peek pressure, according to Hornady I was inside of the perimeters.
https://uploads.tapatalk-cdn.com/20191209/7beaa00f91c178e539c62771cddcd3e8.jpg
[QUOTE=scottcc;2792700]Hmm? It does seem possible the bolt was cycling before peek pressure, according to Hornady I was inside of the perimeters.
Picture is no good but 22.7 is minimum.
https://uploads.tapatalk-cdn.com/20191209/0af2705dc00a4dc8925fdac854efa650.jpg
Anyway I'm just going to stay with Win 748 and Varget that I've used in the past 8 years. I've lost trust in AR Comp.
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Anyway I'm just going to stay with Win 748 and Varget that I've used in the past 8 years. I've lost trust in AR Comp.
Varget is NEARLY kaboom proof in .223. Too hard to get enough of it in the case.
I must admit, my favorite powders are hard for me to visual check each charge due to not filling the case as much as powders that come up to the neck.
Do you use a powder cop? I still drop powder 50 cases at a time, then inspect them all for uniformity. I'd love to get to the point of dropping powder and seating bullet on the progressive, but I think I'd want a lock out die to ensure I don't miss an over or under charged case.
As a rule I stay above min and below max.
Do you use a powder cop? I still drop powder 50 cases at a time, then inspect them all for uniformity. I'd love to get to the point of dropping powder and seating bullet on the progressive, but I think I'd want a lock out die to ensure I don't miss an over or under charged case.
I've never had an under charge with a progressive friendly powder. (I had bridging with IMR 4064 once, but I was expecting trouble with that powder) Otherwise, I just eyeball every case. Any time I've pulled a case due to looking too full, It's been a piece of PMP brass or something with lower case capacity.
Have we determined the cause of this event? I have read through the thread and missed it if identified.
Andy
Have we determined the cause of this event? I have read through the thread and missed it if identified.
Andy
Lotta "noise" and speculation. We know the brass survived its initial firing (factory load), and therefore, in my opinion dismisses the idea that the brass was defective. Assuming the OP didn't anneal the case head, and with the prescribed load of 23.0 gr out of a previously fired case, the base brass idea doesn't work.
Out of battery is pure nonsense.
The case head flow into the barrel extension pretty obviouly (to me) suggests massive over-pressure from an over charge due to some issue with the powder feeding procsess.
Lotta "noise" and speculation. We know the brass survived its initial firing (factory load), and therefore, in my opinion dismisses the idea that the brass was defective. Assuming the OP didn't anneal the case head, and with the prescribed load of 23.0 gr out of a previously fired case, the base brass idea doesn't work.
Out of battery is pure nonsense.
The case head flow into the barrel extension pretty obviouly (to me) suggests massive over-pressure from an over charge due to some issue with the powder feeding procsess.You're right, I must have messed up. I don't know how I errored that bad.
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I wouldn't assume that bolt is still good.
They're cheap enough it would go in the trash and I'd buy another. Heck, I'd be tempted to trash the barrel too.
I agree with getting rid of the bolt and carrier, the barrel is most likely fine although I'd have the barrel extension and locking lugs checked thoroughly for cracks and or movement.
I've had the same type of kaboom, it was a case head failure. The barrel was fine as was the extension but the bolt and carrier were junked.
I'd not shoot any more of that lot of reloads untill they were pulled down and checked and reassembled. Sucks, but better than another kaboom with worse results.
.223 ammo is hardly worth reloading these days, it is cheap and plentiful.
shadowrider
12-13-19, 22:22
Could it be from AR Comp temp sensitive? As I stated it was in June and on a hot day at that. The ammo was in the trunk of the car. I was using metal 20 round mags, they were warm, then setting in the sun made them heat up more, while I was setting things up.
For what it's worth I do trim cases, check OAL and also shake to hear powder.
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Depends on just how hot your ammo actually got. There is a thread on another forum where a guy did some pretty elaborate temp sensitivity testing and found AR Comp pretty good, actually half the variation of Varget. But he only tested up to 165F degrees. Summer...Trunk of car...Metal mags sitting in sun while setting up. That metal mag could've acted like a miniature oven. Elevated ammo temp will increase pressure, maybe not to a degree that hurts anything in a "normal" range of temps but there's a point which it will change and it can change in a rapid and extraordinary fashion. Hard to know if you went past the line.
I suspect you had several things happen. 5.56 case, hot ammo, and a bit of bullet setback...OR...you just simply had a case head failure.
Here is what we are talking about with a web failure.
https://i.imgur.com/uZSqSqCh.jpg
The case on the left is a LC case, the case on the right is a commercial case. Note how much thicker the web area at the bottom of the LC case is. The case on the right will tend to let go first if pressures are right or there is too much exposed case head.
Couple this with the back of the barrel being a tad forward and you have a failure waiting to happen. Similar can happen with soft case head if it got annealed upside down or case has been in a fire.
You provided good information in this thread Humpy70. Do you have a recommendation for how many times a .223 case should be reloaded before being scrapped?
You provided good information in this thread Humpy70. Do you have a recommendation for how many times a .223 case should be reloaded before being scrapped?
Case life depends on multiple things such as:
1. How much bigger is the chamber than the unfired round. Most factory chambers are way too big. The more case swell you see .200 up from the rim the shorter the life is going to be.
2. How much your dies size the cases back down. FL dies are not all the same size thus if you have a min size die and a max chamber your brass gets overworked THAG. The small base dies you read about are just dies chambered with a tired reamer and that allows them to make more dies before they chuck the reamer. I don't own a small base set at all and have never had any feed/extraction problems.
3. Commercial 223 cases as a rule are softer and military cases thus when fired they will expand and this opens the primer pockets up.
4. As indicated above you can tell the left case (LC) is heavier than the commercial case on the right.
5. If you anneal your cases correctly you should never have a split case neck. You should only lose a case because the primer pocket gets worn out and won't grip the primer enough to give a good seal thus gas leakage around the primer will pit bolt face in a circle around the striker opening.
6. There was a shop in the Atlanta area that made a special die that allowed one to size cases all the way down to the rim thus adding to case life. I never got one and wish I had.
As an example of the above lets take my 30.06 chambers for a study. My chambers are cut on the 222 principle which means when the round fires the fired case neck does not expand over .002", the shoulder does not move forward more than .002" and the area above the web does not expand over .002". Thus when a fired case is removed it is very hard to tell it has ever been fired. I sometimes call it the anvil principle which begs the question you likely never saw a worn out anvil which is because it doesn't move.
All the 30.06 ammo I have ever measured shows a head diameter on a new unfired case of .4645-4655. I have four sets of 30.06 dies, one resizes cases to .466, the next .469, the next to .471. I have measured fired cases that show .473 to .475 thus on them I use the .471 die. On my tighter chambers fired cases are sized to .469 or .466. You will find 06 dies size .466 to .469. So basically I know and log on my log book for each rifle what size FL die I use to resize cases.
As a rule military brass from LC is much harder than commercial so should hold up longer. Also you might get Wolfe primers as they are a tad bigger that most milspec small rifle primers.
How long will they last? Don't know. I have one 30.06 LC65 Match case I have loaded 157 times and it is waiting for more. I have 308 rounds with 75 to 90 reloads on them because I use tight chambers. Used to be brass was not expensive, now it pays to have your own reamer made and when you rebarrel rifles have them done with your own reamer so you know what you have.
You should only use MILSPEC primers loading 223/5.56 to insure primers don't reverse flow into striker opening upon firing.
M16 for reliable ignition calls for .022" indent on copper cylinders as they are the second hardest primer in the inventory to ignite. The hardest to ignite if Cal 50 BMG. SAAMI recommendations last I saw "recommend" a min indent of .016". Some vendors have a internal policy of .020" indent.
I have the coppers and the holders to measure striker energy and FAIK I am the only one that does and I can measure 5.56, 308, 30.06 and most magnums. Read my post: https://www.thehighroad.org/index.php?threads/it-dont-go-bang-fires-misfires-hangfires-and-short-order-cooks.850720/
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