My M305 went kaboom

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beavis_m305

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Took it to the range today to test some more ammo out in it. Load was American Eagle (Federal) 150gr FMJBT. Fired the first 3 shots fine. Loaded another two in the mag just to make sure of the POI, let the charging handle go and BANG!. Magazine blew to bits, hand guard popped off (suspect the chamber might have bulged), scope mount came loose, and upon take down found that the entire gas assembly had jumped off it's threads. The case head totally separated and the remainder of the case is stuck in the chamber. There aren't any obvious signs of major damage, but I'm very suspect about whether the rifle is salvageable. I escaped with a nick on my hand, i think the scope mount saved me from getting a heap of hot gas and metal fragments in my face. I was lucky. I'm not 100% sure what happened, but i suspect a slam fire. The thing is I don't know whether it was a high pressure load or whether it detonated before it was fully chambered or both. one of the cases i picked up afterwards had a very flattened primer. I've never had pressure signs with any other ammo I've put through it. It's fired close to 200 rounds no worries. I'm going to contact Reloader supplies who sold me the rifle and Hunting and Fishing who sold me the ammo. Pisses me off some what.


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drache said:
Headspacing problem that caused the slamfire?

*Dont mind me I've been up for 36 hours straight and so Im tired and guessing :p*
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I had some brass cases measured by someone who wanted to compare my rifle to his and another guys. He found that my head spacing was actually tighter than the other samples.
 
Damn.. i dunno.. trying to figure out what the problem could be. For some reason im suspecting that it was more reason for bad ammo.. a possible answer could be that there was wayy too much powder in that round, that can cause all the symptoms that you just had, or a wrong powder type. Or it was just very faulty brass.. you said you fired 200 rounds with no problem, then i don't think it was the rifle, they do what they are made to do. But if your M305 is the chinese one off marstar or w.e the 2010/2011 version was, that made also be the case. I'm not bashing them, but there could be an enhanced possibility that they made a lemon every now and then. I'd be on the same boat as you are right now, speechless and full of questions.
 
Zokakoka said:
Damn.. i dunno.. trying to figure out what the problem could be. For some reason im suspecting that it was more reason for bad ammo.. a possible answer could be that there was wayy too much powder in that round, that can cause all the symptoms that you just had, or a wrong powder type. Or it was just very faulty brass.. you said you fired 200 rounds with no problem, then i don't think it was the rifle, they do what they are made to do. But if your M305 is the chinese one off marstar or w.e the 2010/2011 version was, that made also be the case. I'm not bashing them, but there could be an enhanced possibility that they made a lemon every now and then. I'd be on the same boat as you are right now, speechless and full of questions.
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My ones serial number starts with 2009 so it must be relatively recent manufacture. I'm seriously thinking it was an ammo issue. Curiously, one of the other cases I recovered had a flattened primer
 
Juster said:
Glad you are OK. I'm not sure how a slamfire would take the gas system off.
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May be it was a bit dramatic to say that - the hand guard popped off which i think must have contributed to the gas system coming loose IE: after undoing the gas lock you could slide the gas cylinder down the barrel. I couldn't do that before it happened.
 
Seeing as it fired when you released the cocking handle - not when the trigger was pulled - there is every probability that the rifle fired out of battery, unlocked. That would explain the case separation, missing primer, blown magazine. Highly unlikely the chamber is bulged. The case failure would have resulted in reduced gas pressure in the chamber and barrel - the gas vented backwards, not down the bore. The bullet did exit the bore?
Why it fired out of battery is something you will need to determine.
 
tiriaq said:
Seeing as it fired when you released the cocking handle - not when the trigger was pulled - there is every probability that the rifle fired out of battery, unlocked. That would explain the case separation, missing primer, blown magazine. Highly unlikely the chamber is bulged. The case failure would have resulted in reduced gas pressure in the chamber and barrel - the gas vented backwards, not down the bore. The bullet did exit the bore?
Why it fired out of battery is something you will need to determine.
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Yip it exited. I think maybe the primer on that round was protruding too far. I had cycled another five rounds through it prior to going to the range and they all had indents in their primers. I didn't even notice until I looked at the ammo just before. Had I seen that I probably wouldn't have used it.
 
It is normal for rounds cycled through M-14s, M-1s, ARs, etc to have a mark left on the primer by the firing pin. It results from the floating firing pins used in these designs.
I have never, ever, seen a protruding primer on an unfired factory cartridge.
Given what happened, if you cycled five rounds through the rifle prior to going to the range, you were really lucky that the slamfire did not occur off-range. Could have made for an even worse experience.
I don't know why your rifle fired unlocked. Could be something as simple as grease inside the bolt preventing free movement of the firing pin. Could be a problem with the timing of the camming cut in the receiver and the tail of the firing pin. The rifle is going to have to be inspected by someone very familiar with this type of rifle.
 
tiriaq said:
It is normal for rounds cycled through M-14s, M-1s, ARs, etc to have a mark left on the primer by the firing pin. It results from the floating firing pins used in these designs.
I have never, ever, seen a protruding primer on an unfired factory cartridge.
Given what happened, if you cycled five rounds through the rifle prior to going to the range, you were really lucky that the slamfire did not occur off-range. Could have made for an even worse experience.
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Yeah I'm aware of the floating firing pin thing. I cycled them out on the farm
 
beavis_m305 said:
I think maybe the primer on that round was protruding too far. I had cycled another five rounds through it prior to going to the range and they all had indents in their primers.
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I've fired LOTS of civie commercial ammo through my M14's... BUT, everyone needs to be cognizant of the need to look at the primers & ensure that they are seated properly.

You also need to be careful to use the rifle as intended, ALWAYS load the mag, insert & then release the bolt. NEVER let the bolt fly on a round placed into the chamber! (I know this is not what happened in your case, your mag was damaged, so it had to be in place.) Continuing the thought... Newbies should know that some of the stored spring energy is used to strip the round from the mag & seat it into the chamber.

I've also noticed 'a tap' on primers of rounds that have been cycled through the M14. It's why you should NEVER cycle rounds through the M14 unless you are at the range & the rifle is pointed in a safe direction!

Cheers
Jay
P.S. Thank you for posting! Looking forward to Hungry & M14 Doctor commenting. Glad you're okay!
 
I'm going to go out on a limb here and state my belief:

1) The roud fired out of battery;
2) this was either because of too soft primers (less likely); or
3) Your firing pin was jammed in the forward position.

I'm also going to go ahead and ask the obvious questions:

1) When you got the rifle did you disassemble the bolt and remove every trace of cosmolene?
2) Is your firing pin oiled or lubed in any way? (It should not be).
 
It certainly fired before the lugs locked down, but it was close. You do NOT have what is called a case head separation. Your case separated much further down and AFTER the bolt moved back. The chamber pressure caused the case to separate because the bolt was not there to support the case. First of all the round should not have slam fired. On a M305 that area of bolt rotation is about exactly where the firing pin becomes free to travel, a little less rotation and it is blocked. If they were made a little finer this would not have happened. If the bolt did not have the floating pin blocking design I think any brand of ammo would slam fire so this safety design feature is more of a function than a safety feature. Obviously I do not have the rifle but I would say the rifle is to blame. Mine is the same.

Glad your all right, rifles are easier to replace than fingers or eyes. Have someone check that rifle out. Perhaps the M14 guru on here.
 
I see red goo in yuor locking lug pic. What are you using for grease? try lubriplate,(white lithium grease.) May have gumed up your firing pin like someone said earlier. Call Hungry or m14 Doctor. good luck
 
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