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[ARCHIVED THREAD] - AR Slam fire (Page 1 of 2)
Posted: 1/18/2014 11:24:40 PM EDT
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I had little incident last night, I was putting together a parts list for another AR build and I couldn't remember what brand my charging handle was (BCM Gunfighter) so I unloaded my rifle that I keep next to the bed and when I was done I dropped the round that had come out of the chamber back in and hit the bolt release, this was the result.
http://i1083.photobucket.com/albums/j387/pauljr1283/20140119_022839.jpg The round hit a loaded pmag sitting on my bedside table http://i1083.photobucket.com/albums/j387/pauljr1283/20140119_022246.jpg Then went through the table http://i1083.photobucket.com/albums/j387/pauljr1283/20140119_022909-1.jpg Not a great picture but this is the primer of the offending round http://i1083.photobucket.com/albums/j387/pauljr1283/20140119_022926.jpg Found the bullet laying on the floor http://i1083.photobucket.com/albums/j387/pauljr1283/20140119_034352.jpg Fiocchi 50gr vmax ammo Needless to say it scared the crap out of me but thankfully the table, mag, and 13 rounds were all that were damaged |
| I have some snap caps, I iust dropped the bolt on one 10 times in a row and the hammer stayed back every time. I think this was a result of loading/ unloading the same round too many times and this time the dent was deep enough alread so that the anvil was sruck |
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Do you know approximately how many times you loaded that particular round into the chamber? I dont know for sure but every time I take it to the range I unload it and usually put the same round back in the chamber rough guess it may have been around 5 or 6 times |
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I had little incident last night, I was putting together a parts list for another AR build and I couldn't remember what brand my charging handle was (BCM Gunfighter) so I unloaded my rifle that I keep next to the bed and when I was done I dropped the round that had come out of the chamber back in and hit the bolt release, this was the result. Improper way to load ANY semi-auto firearm. Glad nobody was hurt. |
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I dont know for sure but every time I take it to the range I unload it and usually put the same round back in the chamber rough guess it may have been around 5 or 6 times Quoted:
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Do you know approximately how many times you loaded that particular round into the chamber? I dont know for sure but every time I take it to the range I unload it and usually put the same round back in the chamber rough guess it may have been around 5 or 6 times Stop doing that. The primer takes a small blow from the firing pin every time you chamber a round. Those indentations stack up. I'm not saying that's the cause, but it may be. |
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Improper way to load ANY semi-auto firearm. Glad nobody was hurt. Quoted:
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I had little incident last night, I was putting together a parts list for another AR build and I couldn't remember what brand my charging handle was (BCM Gunfighter) so I unloaded my rifle that I keep next to the bed and when I was done I dropped the round that had come out of the chamber back in and hit the bolt release, this was the result. Improper way to load ANY semi-auto firearm. Glad nobody was hurt. I know that now and will never do it again, will be loading from the mag only from now on! I live alone and there are no neighbors in the direction the gun was pointed so even if the bullet had left the room or worse yet the house the was no chance of someone being hit by it. For as long as i can remember muzzle awareness has been drilled into my brain |
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Glad you are ok OP, but I have several questions as I'm a bit confused. Did you re-chamber the previously chambered round from the magazine?
If so and you went to recharge the gun as you would normally-wouldn't the only time the floating firing pin (FP) been able to strike and ignite via momentum was as the locking lugs had already began their engagement (which naturally occurs and slows the bolts forward momentum, turning the locking lugs to engage the barrel, and then finally locking shut allowing the FP to ding it? The question I guess I am asking to the ARFCOM world is when does the FP dimple the primer? As the bolt begins to lock, When it is slammed shut fully locked Or when the internal buffer weight pops the back of the carrier to keep the bolt locked? |
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Not that I know of, I found all the projectiles but two of the cases are MIA probably in the pile of clothes sitting nearby Quoted:
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Did one of the rounds in the mag detonate? Not that I know of, I found all the projectiles but two of the cases are MIA probably in the pile of clothes sitting nearby It looks like there is burnt powder residue on the inside of the mag and some of the damaged cases which is why I asked..the one case in particular looks like it exploded. |
| This happens enough in military guns that I always admin load milking the f/a to slowly close the bolt. That way loading 25 times is safe and ild rotate rounds when they began to take a beating from feed ramps. I always considered john wayning it with the bolt catch for routine admin loads to be dangerous and stupid. |
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Second time in a week or so. Last guy did similar by dropping the round in and letting the carrier go instead of loading out of a mag. No energy lost in strippng the round. Guess the floating pin hits it with more force. It can happen even loading from a mag though.
http://www.ar15.com/forums/t_3_66/633592_Accidental_Discharge_on_Bolt_Close.html |
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Quoted: Is it possible a firing pin can get stuck forward? So when closing the bolt on a chambered round the primer detonates. Thanks for reminding us to be safe. but a broken fp can fire oob free floating pins + non mil primers can cause what the op did, as well as out of spec primeres |
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The rifle is designed to feed from the magazine, not from "dropping a round into the chamber." When you do that, the round is uncontrolled, it encounters more than just the bolt face and the (very light) contact with the floating firing pin. This is true of just about all magazine-fed firearms, but especially in a firearm with the substantial power of an AR's operating spring behind it. I'd be comfortable putting a little money on the OOB being caused by something other than the firing pin, too. Since the head of the case was uncontrolled, it could have been anything.
When you re-chamber a round, put it in the magazine first. |
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The rifle is designed to feed from the magazine, not from "dropping a round into the chamber." When you do that, the round is uncontrolled, it encounters more than just the bolt face and the (very light) contact with the floating firing pin. This is true of just about all magazine-fed firearms, but especially in a firearm with the substantial power of an AR's operating spring behind it. I'd be comfortable putting a little money on the OOB being caused by something other than the firing pin, too. Since the head of the case was uncontrolled, it could have been anything. When you re-chamber a round, put it in the magazine first. X2 but also check your bore immediately to see that it is clear. |
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OP glad nobody was hurt and you had the firearm pointed away from people.
I had a slam fire at the range, it happens. The pictures show the primer flowed back into the bolt face, since the hammer didn't fall it couldn't hold the firing pin forward as the round fired. 
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Improper way to load ANY semi-auto firearm. Glad nobody was hurt. Quoted:
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I had little incident last night, I was putting together a parts list for another AR build and I couldn't remember what brand my charging handle was (BCM Gunfighter) so I unloaded my rifle that I keep next to the bed and when I was done I dropped the round that had come out of the chamber back in and hit the bolt release, this was the result. Improper way to load ANY semi-auto firearm. Glad nobody was hurt. This, it's a terrible idea to drop the bolt on a chambered round. When I was testing out my DI .45AR for bolt travel, I could make it slam fire every single time I dropped the bolt on a chambered round, but that was with softer pistol primers. |
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not until the bolt is cammed forward but a broken fp can fire oob free floating pins + non mil primers can cause what the op did, as well as out of spec primers Quoted:
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Is it possible a firing pin can get stuck forward? So when closing the bolt on a chambered round the primer detonates. Thanks for reminding us to be safe. but a broken fp can fire oob free floating pins + non mil primers can cause what the op did, as well as out of spec primers Dammit, I just bought a bunch of the same ammo as the OP, just in 55 grain... Guess it will become the first range ammo to get shot up next week... |
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Dammit, I just bought a bunch of the same ammo as the OP, just in 55 grain... Guess it will become the first range ammo to get shot up next week... Quoted:
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Is it possible a firing pin can get stuck forward? So when closing the bolt on a chambered round the primer detonates. Thanks for reminding us to be safe. but a broken fp can fire oob free floating pins + non mil primers can cause what the op did, as well as out of spec primers Dammit, I just bought a bunch of the same ammo as the OP, just in 55 grain... Guess it will become the first range ammo to get shot up next week... It's very rarely an issue when the carrier is slowed by stripping a round from the mag. |
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Did you have your finger on the trigger when you hit the bolt release? If you are holding the trigger and release the bolt carrier the disconnector should stop the hammer from following the carrier and the trigger catches the hammer as you let off. If you pull the trigger afterwards you most likely would have a normal indentation on the primer. |
| I had a slam fire at the range once. Surprised and scared the hell out of me. Dropping the bolt on a round that has never been chambered before. I got slammed here when I said it was a bad idea to drop the bolt on a live round inside your home. It seems to be rare but it happens whether by defected components or re-chambering or whatever but it happens. |
[ARCHIVED THREAD] - AR Slam fire (Page 1 of 2)
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