I blew up my AR!!!!!!!!!!!!!!

Capt_Vin · October 28, 2006, 04:18 AM

I need some ideas on what to look for here. Earlier tonight, I blew up my 4 yr old Bushmaster AR-15. By "blew up", I mean totally destroyed it beyond repair.

Because of the serious nature of what happened, I am going to walk you through exactly what happened including the nitty gritty details. Maybe someone can figure out what exactly went wrong. I apologize if it gets boring, but like I said, detail may mean everything.

My shooting partner and I spent last Sunday reloading our ammo, (.223s) like we usually do in my workshop while the wives were upstairs doing what ever it is wives do when they get together and the kids playing. (My partner and I have been best friends, almost like brothers since we were in grammer school and our families are very close. We have Sunday dinner together every week-end and have done so for many years so, when it comes to reloading me and my friend work like a perfectly tuned and oiled machine). We were using only once fired Remington Brass, which we bought last week (what we do is, one week we will buy ammo at the local gun shop, use it, collect our spent brass and then reload it for the next time we shoot. It saves us alot of money). All of the brass we reloaded , as I said, was only fired once. When we reload, we always faithfully use the same brand powder, same brand primers and same weight leads to keep our shooting results consistant. To us, shooting is a very important sport and is something we have been doing together since we were teen-agers, and we have invested alot of money into our weapons, shooting gear and reloading equipment so we have a proceedure in our reloading that we follow religiously (some say we have boring lives, LOL!) First, we remove the spent primers and as we do this we inspect each and every spent case for any defects such as excessive burn marks, cracks, ect. I check it first, then he does or visa-versa. If we find even one single thing in question, we toss the case into our recycle bucket. After we inspect the brass, we clean the inside of each case with powder solvant and run it through a mechanical tumbler to polish it up. After this is done, we will recheck it, toss any ones we don't like and then get down to business. Next, we use a set of calipers to check the case measurements. We make sure our cases are consistanyly one size. If we find any that need to be trimmed, we will then trim them to size. We then chamfer/ream the necks by hand, ream out the primer pockets by hand and then clean up any burrs. After this is done, we use an air-chuck to blow out any shavings that may be left behind (using low pressure, about 10psi). Next, we reprime the brass using an RCSB auto-primer attachment on my Rock Chucker press. One of us will put the primers in and the other will check each case to make sure they all are uniform in the case. If we find any that aren't uniform, we will pop out the primer and reinstall a fresh one. Then we calibrate the electronic scale we use (we do this every time we reload) and recal the powder dispenser. We will individually weigh each powder load we pull before filling the cases to make sure they are all exactly 24.5 grams on the money. One of us pulls the powder and weighs it, the other will pour the powder into the cases. After all the cases are charged, we will pop in the leads. After all of this is done, we will once again check the bullet length using the electronic calipers to insure uniformity, and then, each completed cartridge will be weighed to again ensure uniformity. After one more quick visial inspection on each one, we will end the session by putting the finished product into plastic cartridge holders and then into our ammo boxes, and the boxes go into a humidity controlled ammo safe. Some may say we are crazy for taking so much time and being so nit-picky in our reloading, but, as I said before, to us, shooting is a very important part of our lives, we take it as serious as some guys take sports like football, and, we have noticed since we became so anal about our reloading technique that our scores have actually improved by a wide margin. Uninterupted, we can usually completely reload a good 400-500 rounds in a good night. During our reloading operation, we do not consume any alcohol and try and keep distractions to an absolute minimum.

After we finish, we will end the night by cleaning our rifles and cleaning up my workshop. (Are ya bored yetLOL!)

Ok, after work today, I went home and picked up my 4 yr old Bushmaster AR-15 and the ammo we reloaded, and met my friend at our gun club. The weather here has absolutely sucked for the last week, heavy rain and temps in the upper 30s to mid 40s. We set up and started shooting at 200 yards without scopes. We make it a point that after each 100 rounds fired, we give the weapons a quick but thorough field cleaning. Anyway, somewhere around 120 or so rounds each into our shooting, (we slow shoot, manually loading one cartridge at a time) I put a round in, took aim (I was shooting in the kneeling position) and squeezed off the round. The round just blew right in the rifle. It went off so hard that it actually blew a small piece of the lower reciever off (if you took a dime and cut it into 4ths, that is how big the piece was). It sounded and felt like someone lit off a cherry bomb in front of me. The blast caused me to reflexively drop the rifle, but because of the way I was using the sling, it didn't hit the ground, except for the buttstock. Luckly, I didn't get hurt, just scared ****less. After I regained my senses and telling my buddy and the other 4 people who were shooting that I was ok, did I look at my AR. It was wasted. Aside from the little piece missing from the lower reciever, the the immediate other damage I noticed was the fire select was pushed out, the front pivot pin appeared bent, the takedown pin was gone and the trigger was completely jammed.
Being as pissed as I was, we packed it in and went straight to my house to strip the rifle down to see what else was damaged. With some difficulty due to the bent pivot pin, we managed to open it up and found the following:
trigger assembly broken and scorched, firing pin in two pieces, firing pin retainer broken, gas rings scorched and broke, forward assist shaft slightly bent and pieces of the broken brass casing jammed up in everything. The lead slug was stuck in the barrel about 10 inches down (my AR has (uh, had)a 20 inch barrel). Also, every part in the recievers was scorched from the powder in one way or another.

There you go. The details. Can anyone take a wild guess on what could have gone wrong? My first thought was maybe we accidently double charged one of the cartridges, but as I said, we weigh each one AFTER we complete the reloading procedure. My friend seems to think maybe it was caused by some type of blockage in the barrel, but I dunno with that much damage. Any ideas will be appriciated. I am going to have a qualified gunsmith look at it and see if he can figure out what happened and if it is salvageable, hopefully most of it will be, but I know the lower is gone along with the trigger and a few other pins and parts. For now, I guess I will be taking a break from shooting until I replace the AR or have it repaired.

As I said, any ideas will be appriciated, and as soon as I can figure out how to do it, I will post the pictures we took of the rifle before we disassembled it and after, showing the damaged inners.

rangermonroe · October 28, 2006, 07:18 AM

My first thought would be a bullet remained lodged in the bbl, but I believe you would notice a squib.

I wonder if the bolt was not locked up with the bbl. The bottom of the carrier should keep the hammer from striking the firing pin of it is not all the way home.

Have you checked out the guys at AR-15 com? There may be somone over there who has more info than I.

I'm glad you are ok.

SmokinTom · October 28, 2006, 07:51 AM

OUCH!!! Well here goes.It is possible that you didn`t have enough powder in the case so when it fired the powder didn`t burn,it detonated,just like a little bomb in the chamber.The AR15-M16 should not fire the round if the bolt is not locked fully into the barrel extension(breach).I`m guessing the bomb in the chamber thing.

rangermonroe · October 28, 2006, 09:09 AM

Was the upper receiver and bbl damaged? Or was the damage to the lower and fire control group?

Ausserordeutlich · October 28, 2006, 09:41 AM

Having suffered through your third paragraph, I'd hazard a guess that God's just made an attempt at saving you from hours and hours of superfluous reloading tedium.

Ever tried to put 49 grains of any powder in a .223 case? Can't be done; you didn't doublecharge, that's for sure.

Mac's! · October 28, 2006, 10:00 AM

I had a .223 blow up in my face...twice! These were both hand loads made by me in my shop. The backs of the cases blew off...the first one was just a bang and a few minor powder burns on my face. I thought..hmm..bad case. The second one destroyed the rifle and put shrapnel into my face.
I concluded that it was an ammo problem so I had an expert look at the blown up cases and some more of my un-fired hand loads.
It turned out that my de-burring process was not doing the job. It was leaving a slight ridge around the outside of the neck of the case. That ridge was being crimped even tighter when the cartridge was chambered. Some ridges were bigger than others and at some point, it took less pressure to blow the cartridge up than to push the bullet out the front. Big BOOM!
I disabled all remaining ammo that I had loaded. Also just FYI: The chamber area of the barrel had many hairline fractures that were not visible to the naked eye.
Kep yer powder dry, Mac.
Tuff-Gun Finishes. The Name Says It All.
Mac's Shootin' Irons
http://www.shootiniron.com

HSMITH · October 28, 2006, 12:17 PM

I would almost bet it was a bore obstruction of some kind.

DnPRK · October 28, 2006, 01:31 PM

You keep saying lead. Were you shooting cast lead bullets or copper jacketed bullets?

Capt_Vin · October 29, 2006, 12:57 AM

DnPRK, by "lead", I mean the projectile. We always use the same reload 'formula', never more than once fired (by us) Remington brass, 67 grain FMJ Federal 'leads', CCI primers, and 24.5 gr of premium (the "good stuff" as we call it)Winchester powder. (One of my club members thought maybe we combined the bottom of one can of powder with a freshly opened one and it caused the problem, but we never mix powder from one can to another. If we have left-over, we will reload more until it is gone, or just pop a fresh can.)

Well, I spent a better part of this morning "performing an autopsy" on my rifle as my wife called what i was doing trying to humor me out of the really nasty mood I was in over this accident (sorry, honey for being such a grouch). I went over every square inch of the thing, looking for even the smallest tell-tale sign of what may have happened. I couldn't find anything at all that was or appeared to have been wrong with the rifle. My shooting partner Scott stopped by to see how I was making out and to show me something he discovered. It seems that maybe 1/4 of our brass that we picked up after the accident looked like there was a slight inward 'ding' just below the neck rim. The rest of the brass seemed fine. We grabbed about 100 of the remaining loads and headed to Scott's house to get his rifle, the same model Bushmaster as mine and then drove out to the club, despite the weather, which was almost as foul as I was at this point. Scott's rifle is identicle to mine, except his has a different trigger. We managed to fire 60 rounds before the 30mph+ wind started making the rain unbearable, and after collecting all the spent brass, we headed back to my house to examine it. Well, none of the brass had the 'ding' in it. For haa-haas, I decided to see if I could dislodge the bullet that was stuck in the barrel of my AR without damaging it any further, and after a few minutes of working at it, pushing it out towards the muzzle end with a wooden dowel, I managed to get it out. Sure as hell, there was a 'groove', more like a very small scratch, in the slug's copper jacket. The fore-end of the barrel is scorched pretty bad and slightly messed up from the explosion, but I am now leaning towards what Mac's and Rangemonroe are hinting at, some type of bore obstruction or something like that. Maybe there was something in my barrel that caused the rim to crimp down on the bullet and cause the round to detonate. It would explain the marks on the spent brass, which obviously didn't come from Scott's rifle. I am wondering if maybe when I ran my cleaning rod through the rifle that maybe the steel rod nicked the end of the barrel just enough to damage it in a way that it would cause this.
On the happier side, my wife called our insurance agent while we were out at the club 'playing detective' and she found out that the policy we have for our firearms will cover about 80% of the cost to replace the rifle. Our agent told her that because the gun was destroyed by means other than theft, negligance or misuse, we are covered. I am glad we opted for the better policy when we bought the policy 2 yrs ago. Yes, our premium is slightly higher than the standard no-frills policy, but I can now see the extra $40 a year was worth it. On Monday, i am dropping the remains of my AR off to a friend who is a certified gunsmith to have him look at the rifle to see if he can figure out what the exact cause was, but now, I am going to show him the brass and see if my theroy floats. I will post what his opinion is as soon as he finishes.

Alakar · October 29, 2006, 01:37 AM

Quote:

I am wondering if maybe when I ran my cleaning rod through the rifle that maybe the steel rod nicked the end of the barrel just enough to damage it in a way that it would cause this.

The cleaning rod theory isn't very likely. I spent 12 years in a Army arms repair shop, and never saw cleaning rod damage that would cause something like this and Army cleaning rods are steel.

What did the bolt lugs and barrel extension lugs look like? Were they sheared off or mostly intact? Did any of the cartridge case survive? What did the chamber look like?

If the lugs aren't sheared, it looks like the bolt never locked. Since the bullet was only 10" down the barrel the gas never reached the gas port, and the bolt carrier wouldn't have moved rearward to unlock the bolt. That can only mean the bolt didn't lock.

Is it possible the cam pin broke? That would keep the bolt from rotating and locking, but not prevent the bolt and carrier from moving fully forward.

roadrash · October 29, 2006, 05:57 AM

Sounds like it fired out of battery!

rangermonroe · October 29, 2006, 09:26 AM

Quote:

Like the cam pin broke

Maybe the cotter pin was not put in?

I was thinking the same thing, if the bullet was lodged in the bore, "south" of the gas port...it had to fire without being locked up.

Is it possible that there was a "double feed" with the tip of the second round detonating the primer of the first?

Quote:

On the happier side, my wife called our insurance agent while we were out at the club 'playing detective' and she found out that the policy we have for our firearms will cover about 80% of the cost to replace the rifle. Our agent told her that because the gun was destroyed by means other than theft, negligance or misuse, we are covered.

I would not ever use my homeowners insurance to cover anything but catastrophic losses. State Farm and Allstate are known for cancelling policies after the very first claim. Try getting insurance after being cancelled!

After your deductible is paid, how much is 80% of a Bushmaster? $500-600?

ClarkEMyers · October 29, 2006, 10:50 AM

Quote:

We will individually weigh each powder load we pull before filling the cases to make sure they are all exactly 24.5 grams on the money

It couldn't have been 24.5 grams in a .223/5.56 - what was the powder charge when you pulled down one of the loaded cartridges? Grains maybe?

Guessing the powder is 748 I don't see that as an issue assuming 24.5 grains and certainly not blowing the rifle AND lodging the bullet with anything even close different lots or not.

It does sound to me as though the rifle fired unlocked - I'd doubt a barrel obstruction that was forward of the lodged bullet and disappeared - pushed out by the airflow ahead of the bullet and yet blew the rifle rather than ringing the barrel. I'd do a mag penetrant dye check and look for previous cracks or signs of improper assembly crimp what have you.

I understand the rifle was fired 100 times with the reloads from the same lot then opened and stripped for cleaning then reassembled and fired about 20 times with good results then fired once more for a kaboom?

Quote:

somewhere around 120 or so rounds each into our shooting, (we slow shoot, manually loading one cartridge at a time) I put a round in, took aim (I was shooting in the kneeling position) and squeezed off the round. The round just blew right in the rifle

What is your process for single loading? Do you use some sort of single shot adapter -SLED style or a single load through through the ejection port with an empty magazine or feed from the magazine? Maybe a bullet setback?

VaFisher · October 29, 2006, 02:30 PM

I would have to agree with Alakar.
If the lugs aren't sheared, it looks like the bolt never locked. Since the bullet was only 10" down the barrel the gas never reached the gas port, and the bolt carrier wouldn't have moved rearward to unlock the bolt. That can only mean the bolt didn't lock.

Being you were shooting these single style it would be more understandable that the bolt was not fully close.

James K · October 29, 2006, 08:33 PM

Unless the firing pin is protruding (due to breakage), it is impossible to get an AR-15 to fire without being locked. And if the firing pin is protruding, the rifle will fire as the bolt closes; it won't wait until the trigger is pulled. I think some more analysis is needed.

Jim

Bogie · October 30, 2006, 12:11 AM

Just a guess here - Did you "ride" the bolt handle down as you were loading the single-shot rounds?

Alakar · October 30, 2006, 12:46 PM

Quote:

Unless the firing pin is protruding (due to breakage), it is impossible to get an AR-15 to fire without being locked. And if the firing pin is protruding, the rifle will fire as the bolt closes; it won't wait until the trigger is pulled. I think some more analysis is needed.

If the cam pin breaks a AR-15 can fire without being locked. The bolt and bolt carrier can slide fully forward into battery, but the bolt never rotates to engage the locking lugs. I have seen this occur only twice. Usually a broken cam pin will not break cleanly and will jam up the action of the weapon. But on those two occasions, the cam pin broke cleanly at the surface of the the cam pin hole in the bolt. When the carrier came forward the bolt was able to slide back into the carrier making it look like the weapon was locked.

We tested out the theory with one of the broken cam pins. We installed it in a functioning weapon, let the bolt and carrier slide into battery, and were able to push the bolt and carrier assembly back by pushing on the bolt face with a cleaning rod down the barrel. In this instance, the problems were caused by a bad lot of cam pins that would crack and break after 100 to 300 rds.

dfaugh · October 30, 2006, 01:18 PM

Quote:

Sounds like it fired out of battery!

That and a barrel obstruction of some kind would be my 2 gueses.

James K · October 30, 2006, 08:34 PM

Thanks, Alakar. I had not heard of that happening but the result would certainly be as described, and that condition would wait until the trigger was pulled.

Of course, the same thing would happen if the rifle were assembled without the cam pin, but Capt_Vin had fired a number of rounds so that could not have been the problem. (In fact, getting the bolt to close without the cam pin is surprisingly difficult.)

I hope we can get some definitive answers from the "autopsy."

Jim

**Unclenick** · October 30, 2006, 08:38 PM

Capt_Vin

I like the broken cam pin theory. Can you look to verify it one way or another? Since you measure your loaded rounds, it seems unlikely you would have had a primer high enough to cause a slam-fire ahead of the bolts locking, but it's still a theoretical possibility and the only other cause of an unlocked discharge that occurs to me, assuming you have no lug damage.

The dings in the case necks are probably just a bump occurring on ejection. Putting a serious dent through a neck and into the bullet on chambering seems unlikely. The force required would probably cause a jam, though I have seen bullets tipped severely enough to bend a case neck because they attempted to chamber from an extreme angle. This is possible to do if you don't use a SLED for single loading, but not likely to occur regularly or to produce the same exact damage each time. Moreover, a Lee Factory Crimp die for high power cartridges puts a circumferential neck and bullet indentation intentionally into each round, and these blow open just fine. So, it isn’t likely a dented neck and bullet could be the cause of a pressure event like you described.

I didn’t notice your loading routine including a comparative visual check of powder level in your cases after charging them. Since you are weighing each charge, you may think it unnecessary? But, gremlins abound, so it is always a good idea to have the charged cases in a loading tray so you can do the flashlight once-over to be doubly sure they look the same.

I would be careful about the air nozzle you use to blow out cases. Every compressor I’ve ever had would shoot a bit of moisture and oil from time to time; usually accumulated in the short hose between the nozzle and coalescing-type water filter. It takes a powered chilling condenser filter to really dry compressed air out. A drop of wet oil that contaminated a portion of the powder might result in unexpected effects. Let us know about whether you had any lug damage?

Nick

Tim R · November 3, 2006, 03:11 AM

Quote:

Unless the firing pin is protruding (due to breakage), it is impossible to get an AR-15 to fire without being locked. And if the firing pin is protruding, the rifle will fire as the bolt closes; it won't wait until the trigger is pulled. I think some more analysis is needed.

Hate to argue but the AR has a free floating firing pin. Remove a chambered but not fired round and you will find the primer will have a "dimple" on it from the firing pin. A high primer could fire out of battery.

The way I read the org posters story is he loaded and then took aim. I wonder if there wasn't something left over from cleaning.

Capt_Vin · November 7, 2006, 11:39 PM

Well, we have solved the mystery. I had a certified gunsmith who is very familiar with ARs look at the remains and his conclusion is that my lower reciever had a stress crack in it just in front of where the magazine catch is and the repeat pressures from shooting finally caused the thing to blow. I questioned this theroy until he showed me what led him to this "existing crack" idea. The edges of the crack, along where the piece broke off, had more "burn" to it than the rest. I don't wanna call it rust, so to speak, but by looking closely at it with a magnifying glass, you can see by color difference, what was old and what was new damage. He also said I had a stress crack in the right side of the lower where the front pivot pin slides in. He thinks that it would have gone sooner or later. He told me, just be thankful it didn't cause more injury that just to my wallet. And I am.

As far as my insurance goes, we sat down with our agent (who is also a friend of my wife's husband) and he explained that because of our the way policy is written, it will cover the replacement, but.........it is gonna jack the rates up 10%/year. I am still deciding, but on the bright side, I ordered my new AR and should have it in a few days. It's a DPMS with a few modifications (barrel swap, trigger change). Price wasn't that bad, below $900.00. Hopefully, this one will outlive me, LOL!

Venison_Jerkey32 · November 8, 2006, 12:10 AM

Quote:

wife's husband

pax · November 8, 2006, 01:03 AM

venison ~

I caught that too and had to read it four times before I figured out he probably meant, "the husband of a friend of my wife."

pax

hodaka · November 8, 2006, 06:58 AM

Well Capt,

I'm certainly not a certified gunsmith, just a guy who likes to assemble and shoot AR's, but I fail to see how a crack in the lower could lead to an explosion. As I see it, once the bolt locks into the barrel extension, the lower is irrelevant to the firing, other than to control the hammer. I've been following this thread and I tend to believe, as suggested above, the cam failed and the rifle fired out of battery. The lower may well have been previously cracked, but I do not think it caused the kaboom.

October 28, 2006, 04:18 AM	#1
Capt_Vin Senior Member Join Date: January 4, 2006 Posts: 266	I blew up my AR!!!!!!!!!!!!!! I need some ideas on what to look for here. Earlier tonight, I blew up my 4 yr old Bushmaster AR-15. By "blew up", I mean totally destroyed it beyond repair. Because of the serious nature of what happened, I am going to walk you through exactly what happened including the nitty gritty details. Maybe someone can figure out what exactly went wrong. I apologize if it gets boring, but like I said, detail may mean everything. My shooting partner and I spent last Sunday reloading our ammo, (.223s) like we usually do in my workshop while the wives were upstairs doing what ever it is wives do when they get together and the kids playing. (My partner and I have been best friends, almost like brothers since we were in grammer school and our families are very close. We have Sunday dinner together every week-end and have done so for many years so, when it comes to reloading me and my friend work like a perfectly tuned and oiled machine). We were using only once fired Remington Brass, which we bought last week (what we do is, one week we will buy ammo at the local gun shop, use it, collect our spent brass and then reload it for the next time we shoot. It saves us alot of money). All of the brass we reloaded , as I said, was only fired once. When we reload, we always faithfully use the same brand powder, same brand primers and same weight leads to keep our shooting results consistant. To us, shooting is a very important sport and is something we have been doing together since we were teen-agers, and we have invested alot of money into our weapons, shooting gear and reloading equipment so we have a proceedure in our reloading that we follow religiously (some say we have boring lives, LOL!) First, we remove the spent primers and as we do this we inspect each and every spent case for any defects such as excessive burn marks, cracks, ect. I check it first, then he does or visa-versa. If we find even one single thing in question, we toss the case into our recycle bucket. After we inspect the brass, we clean the inside of each case with powder solvant and run it through a mechanical tumbler to polish it up. After this is done, we will recheck it, toss any ones we don't like and then get down to business. Next, we use a set of calipers to check the case measurements. We make sure our cases are consistanyly one size. If we find any that need to be trimmed, we will then trim them to size. We then chamfer/ream the necks by hand, ream out the primer pockets by hand and then clean up any burrs. After this is done, we use an air-chuck to blow out any shavings that may be left behind (using low pressure, about 10psi). Next, we reprime the brass using an RCSB auto-primer attachment on my Rock Chucker press. One of us will put the primers in and the other will check each case to make sure they all are uniform in the case. If we find any that aren't uniform, we will pop out the primer and reinstall a fresh one. Then we calibrate the electronic scale we use (we do this every time we reload) and recal the powder dispenser. We will individually weigh each powder load we pull before filling the cases to make sure they are all exactly 24.5 grams on the money. One of us pulls the powder and weighs it, the other will pour the powder into the cases. After all the cases are charged, we will pop in the leads. After all of this is done, we will once again check the bullet length using the electronic calipers to insure uniformity, and then, each completed cartridge will be weighed to again ensure uniformity. After one more quick visial inspection on each one, we will end the session by putting the finished product into plastic cartridge holders and then into our ammo boxes, and the boxes go into a humidity controlled ammo safe. Some may say we are crazy for taking so much time and being so nit-picky in our reloading, but, as I said before, to us, shooting is a very important part of our lives, we take it as serious as some guys take sports like football, and, we have noticed since we became so anal about our reloading technique that our scores have actually improved by a wide margin. Uninterupted, we can usually completely reload a good 400-500 rounds in a good night. During our reloading operation, we do not consume any alcohol and try and keep distractions to an absolute minimum. After we finish, we will end the night by cleaning our rifles and cleaning up my workshop. (Are ya bored yetLOL!) Ok, after work today, I went home and picked up my 4 yr old Bushmaster AR-15 and the ammo we reloaded, and met my friend at our gun club. The weather here has absolutely sucked for the last week, heavy rain and temps in the upper 30s to mid 40s. We set up and started shooting at 200 yards without scopes. We make it a point that after each 100 rounds fired, we give the weapons a quick but thorough field cleaning. Anyway, somewhere around 120 or so rounds each into our shooting, (we slow shoot, manually loading one cartridge at a time) I put a round in, took aim (I was shooting in the kneeling position) and squeezed off the round. The round just blew right in the rifle. It went off so hard that it actually blew a small piece of the lower reciever off (if you took a dime and cut it into 4ths, that is how big the piece was). It sounded and felt like someone lit off a cherry bomb in front of me. The blast caused me to reflexively drop the rifle, but because of the way I was using the sling, it didn't hit the ground, except for the buttstock. Luckly, I didn't get hurt, just scared ****less. After I regained my senses and telling my buddy and the other 4 people who were shooting that I was ok, did I look at my AR. It was wasted. Aside from the little piece missing from the lower reciever, the the immediate other damage I noticed was the fire select was pushed out, the front pivot pin appeared bent, the takedown pin was gone and the trigger was completely jammed. Being as pissed as I was, we packed it in and went straight to my house to strip the rifle down to see what else was damaged. With some difficulty due to the bent pivot pin, we managed to open it up and found the following: trigger assembly broken and scorched, firing pin in two pieces, firing pin retainer broken, gas rings scorched and broke, forward assist shaft slightly bent and pieces of the broken brass casing jammed up in everything. The lead slug was stuck in the barrel about 10 inches down (my AR has (uh, had)a 20 inch barrel). Also, every part in the recievers was scorched from the powder in one way or another. There you go. The details. Can anyone take a wild guess on what could have gone wrong? My first thought was maybe we accidently double charged one of the cartridges, but as I said, we weigh each one AFTER we complete the reloading procedure. My friend seems to think maybe it was caused by some type of blockage in the barrel, but I dunno with that much damage. Any ideas will be appriciated. I am going to have a qualified gunsmith look at it and see if he can figure out what happened and if it is salvageable, hopefully most of it will be, but I know the lower is gone along with the trigger and a few other pins and parts. For now, I guess I will be taking a break from shooting until I replace the AR or have it repaired. As I said, any ideas will be appriciated, and as soon as I can figure out how to do it, I will post the pictures we took of the rifle before we disassembled it and after, showing the damaged inners.

October 30, 2006, 12:11 AM	#16
Bogie Senior Member Join Date: June 5, 2000 Location: Job hunting on the road... Posts: 3,827	Just a guess here - Did you "ride" the bolt handle down as you were loading the single-shot rounds? __________________ Job hunting, but helping a friend out at www.vikingmachineusa.com - and learning the finer aspects of becoming a precision machinist. And making the world's greatest bottle openers!

October 30, 2006, 08:38 PM	#20
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	Capt_Vin I like the broken cam pin theory. Can you look to verify it one way or another? Since you measure your loaded rounds, it seems unlikely you would have had a primer high enough to cause a slam-fire ahead of the bolts locking, but it's still a theoretical possibility and the only other cause of an unlocked discharge that occurs to me, assuming you have no lug damage. The dings in the case necks are probably just a bump occurring on ejection. Putting a serious dent through a neck and into the bullet on chambering seems unlikely. The force required would probably cause a jam, though I have seen bullets tipped severely enough to bend a case neck because they attempted to chamber from an extreme angle. This is possible to do if you don't use a SLED for single loading, but not likely to occur regularly or to produce the same exact damage each time. Moreover, a Lee Factory Crimp die for high power cartridges puts a circumferential neck and bullet indentation intentionally into each round, and these blow open just fine. So, it isn’t likely a dented neck and bullet could be the cause of a pressure event like you described. I didn’t notice your loading routine including a comparative visual check of powder level in your cases after charging them. Since you are weighing each charge, you may think it unnecessary? But, gremlins abound, so it is always a good idea to have the charged cases in a loading tray so you can do the flashlight once-over to be doubly sure they look the same. I would be careful about the air nozzle you use to blow out cases. Every compressor I’ve ever had would shoot a bit of moisture and oil from time to time; usually accumulated in the short hose between the nozzle and coalescing-type water filter. It takes a powered chilling condenser filter to really dry compressed air out. A drop of wet oil that contaminated a portion of the powder might result in unexpected effects. Let us know about whether you had any lug damage? Nick __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

November 7, 2006, 11:39 PM	#22
Capt_Vin Senior Member Join Date: January 4, 2006 Posts: 266	Official Autopsy Results Well, we have solved the mystery. I had a certified gunsmith who is very familiar with ARs look at the remains and his conclusion is that my lower reciever had a stress crack in it just in front of where the magazine catch is and the repeat pressures from shooting finally caused the thing to blow. I questioned this theroy until he showed me what led him to this "existing crack" idea. The edges of the crack, along where the piece broke off, had more "burn" to it than the rest. I don't wanna call it rust, so to speak, but by looking closely at it with a magnifying glass, you can see by color difference, what was old and what was new damage. He also said I had a stress crack in the right side of the lower where the front pivot pin slides in. He thinks that it would have gone sooner or later. He told me, just be thankful it didn't cause more injury that just to my wallet. And I am. As far as my insurance goes, we sat down with our agent (who is also a friend of my wife's husband) and he explained that because of our the way policy is written, it will cover the replacement, but.........it is gonna jack the rates up 10%/year. I am still deciding, but on the bright side, I ordered my new AR and should have it in a few days. It's a DPMS with a few modifications (barrel swap, trigger change). Price wasn't that bad, below $900.00. Hopefully, this one will outlive me, LOL!

November 8, 2006, 01:03 AM	#24
pax Senior Member Join Date: May 16, 2000 Location: In a state of flux Posts: 7,520	venison ~ I caught that too and had to read it four times before I figured out he probably meant, "the husband of a friend of my wife." pax __________________ Kathy Jackson My personal website: Cornered Cat

October 28, 2006, 07:18 AM	#2
rangermonroe Senior Member Join Date: January 27, 2005 Location: savannah Posts: 758	My first thought would be a bullet remained lodged in the bbl, but I believe you would notice a squib. I wonder if the bolt was not locked up with the bbl. The bottom of the carrier should keep the hammer from striking the firing pin of it is not all the way home. Have you checked out the guys at AR-15 com? There may be somone over there who has more info than I. I'm glad you are ok.

October 28, 2006, 07:51 AM	#3
SmokinTom Senior Member Join Date: November 29, 2004 Location: Ohio Posts: 479	OUCH!!! Well here goes.It is possible that you didn`t have enough powder in the case so when it fired the powder didn`t burn,it detonated,just like a little bomb in the chamber.The AR15-M16 should not fire the round if the bolt is not locked fully into the barrel extension(breach).I`m guessing the bomb in the chamber thing.

October 28, 2006, 09:09 AM	#4
rangermonroe Senior Member Join Date: January 27, 2005 Location: savannah Posts: 758	Was the upper receiver and bbl damaged? Or was the damage to the lower and fire control group?

October 28, 2006, 09:41 AM	#5
Ausserordeutlich Junior member Join Date: May 27, 2006 Posts: 996	Having suffered through your third paragraph, I'd hazard a guess that God's just made an attempt at saving you from hours and hours of superfluous reloading tedium. Ever tried to put 49 grains of any powder in a .223 case? Can't be done; you didn't doublecharge, that's for sure.

October 28, 2006, 10:00 AM	#6
Mac's! Senior Member Join Date: August 15, 2001 Posts: 129	I had a .223 blow up in my face...twice! These were both hand loads made by me in my shop. The backs of the cases blew off...the first one was just a bang and a few minor powder burns on my face. I thought..hmm..bad case. The second one destroyed the rifle and put shrapnel into my face. I concluded that it was an ammo problem so I had an expert look at the blown up cases and some more of my un-fired hand loads. It turned out that my de-burring process was not doing the job. It was leaving a slight ridge around the outside of the neck of the case. That ridge was being crimped even tighter when the cartridge was chambered. Some ridges were bigger than others and at some point, it took less pressure to blow the cartridge up than to push the bullet out the front. Big BOOM! I disabled all remaining ammo that I had loaded. Also just FYI: The chamber area of the barrel had many hairline fractures that were not visible to the naked eye. Kep yer powder dry, Mac. Tuff-Gun Finishes. The Name Says It All. Mac's Shootin' Irons http://www.shootiniron.com

October 28, 2006, 12:17 PM	#7
HSMITH Senior Member Join Date: June 21, 2002 Posts: 2,019	I would almost bet it was a bore obstruction of some kind.

October 28, 2006, 01:31 PM	#8
DnPRK Senior Member Join Date: August 24, 2001 Location: LC, Ca Posts: 1,917	You keep saying lead. Were you shooting cast lead bullets or copper jacketed bullets?

October 29, 2006, 12:57 AM	#9
Capt_Vin Senior Member Join Date: January 4, 2006 Posts: 266	DnPRK, by "lead", I mean the projectile. We always use the same reload 'formula', never more than once fired (by us) Remington brass, 67 grain FMJ Federal 'leads', CCI primers, and 24.5 gr of premium (the "good stuff" as we call it)Winchester powder. (One of my club members thought maybe we combined the bottom of one can of powder with a freshly opened one and it caused the problem, but we never mix powder from one can to another. If we have left-over, we will reload more until it is gone, or just pop a fresh can.) Well, I spent a better part of this morning "performing an autopsy" on my rifle as my wife called what i was doing trying to humor me out of the really nasty mood I was in over this accident (sorry, honey for being such a grouch). I went over every square inch of the thing, looking for even the smallest tell-tale sign of what may have happened. I couldn't find anything at all that was or appeared to have been wrong with the rifle. My shooting partner Scott stopped by to see how I was making out and to show me something he discovered. It seems that maybe 1/4 of our brass that we picked up after the accident looked like there was a slight inward 'ding' just below the neck rim. The rest of the brass seemed fine. We grabbed about 100 of the remaining loads and headed to Scott's house to get his rifle, the same model Bushmaster as mine and then drove out to the club, despite the weather, which was almost as foul as I was at this point. Scott's rifle is identicle to mine, except his has a different trigger. We managed to fire 60 rounds before the 30mph+ wind started making the rain unbearable, and after collecting all the spent brass, we headed back to my house to examine it. Well, none of the brass had the 'ding' in it. For haa-haas, I decided to see if I could dislodge the bullet that was stuck in the barrel of my AR without damaging it any further, and after a few minutes of working at it, pushing it out towards the muzzle end with a wooden dowel, I managed to get it out. Sure as hell, there was a 'groove', more like a very small scratch, in the slug's copper jacket. The fore-end of the barrel is scorched pretty bad and slightly messed up from the explosion, but I am now leaning towards what Mac's and Rangemonroe are hinting at, some type of bore obstruction or something like that. Maybe there was something in my barrel that caused the rim to crimp down on the bullet and cause the round to detonate. It would explain the marks on the spent brass, which obviously didn't come from Scott's rifle. I am wondering if maybe when I ran my cleaning rod through the rifle that maybe the steel rod nicked the end of the barrel just enough to damage it in a way that it would cause this. On the happier side, my wife called our insurance agent while we were out at the club 'playing detective' and she found out that the policy we have for our firearms will cover about 80% of the cost to replace the rifle. Our agent told her that because the gun was destroyed by means other than theft, negligance or misuse, we are covered. I am glad we opted for the better policy when we bought the policy 2 yrs ago. Yes, our premium is slightly higher than the standard no-frills policy, but I can now see the extra $40 a year was worth it. On Monday, i am dropping the remains of my AR off to a friend who is a certified gunsmith to have him look at the rifle to see if he can figure out what the exact cause was, but now, I am going to show him the brass and see if my theroy floats. I will post what his opinion is as soon as he finishes.

October 29, 2006, 05:57 AM	#11
roadrash Senior Member Join Date: February 18, 2005 Posts: 367	Sounds like it fired out of battery!

October 29, 2006, 02:30 PM	#14
VaFisher Senior Member Join Date: January 24, 2006 Posts: 596	I would have to agree with Alakar. If the lugs aren't sheared, it looks like the bolt never locked. Since the bullet was only 10" down the barrel the gas never reached the gas port, and the bolt carrier wouldn't have moved rearward to unlock the bolt. That can only mean the bolt didn't lock. Being you were shooting these single style it would be more understandable that the bolt was not fully close.

October 29, 2006, 08:33 PM	#15
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	Unless the firing pin is protruding (due to breakage), it is impossible to get an AR-15 to fire without being locked. And if the firing pin is protruding, the rifle will fire as the bolt closes; it won't wait until the trigger is pulled. I think some more analysis is needed. Jim

October 30, 2006, 08:34 PM	#19
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	Thanks, Alakar. I had not heard of that happening but the result would certainly be as described, and that condition would wait until the trigger was pulled. Of course, the same thing would happen if the rifle were assembled without the cam pin, but Capt_Vin had fired a number of rounds so that could not have been the problem. (In fact, getting the bolt to close without the cam pin is surprisingly difficult.) I hope we can get some definitive answers from the "autopsy." Jim

November 8, 2006, 06:58 AM	#25
hodaka Senior Member Join Date: April 23, 2006 Location: South Texas Posts: 2,010	Well Capt, I'm certainly not a certified gunsmith, just a guy who likes to assemble and shoot AR's, but I fail to see how a crack in the lower could lead to an explosion. As I see it, once the bolt locks into the barrel extension, the lower is irrelevant to the firing, other than to control the hammer. I've been following this thread and I tend to believe, as suggested above, the cam failed and the rifle fired out of battery. The lower may well have been previously cracked, but I do not think it caused the kaboom.