Why did it fire 4 times before exploding?

[ARCHIVED THREAD] - Why did it fire 4 times before exploding?

Posted: 10/27/2004 2:57:35 PM EDT

I know everyone says "You should have KNOWN that fring an AR underwater will detonate the gun!!!"

But, why did the first FOUR shots not detonate the gun?

Why did it wait for the fifth round to KB?

If it ABSOLUTELY was going to KB, why not on the first round?

TRG

Posted: 10/27/2004 2:59:17 PM EDT

[#1]

Maybe the barrel filled with water before the fourth round was fired.

Posted: 10/27/2004 3:01:12 PM EDT

[#2]

Quoted:
Maybe the barrel filled with water before the fourth round was fired.

How? Gas pressure should have cleared the barrel. Gas in the recoil system probably blew air in to the chamber.

He was 'bumbfiring, so I assumed it was a pretty quick succession of shots?

1,2,3,4 then BOOM?

TRG

Posted: 10/27/2004 3:01:25 PM EDT

[#3]

I think it took that many rounds to pump enough water into the gas system. The bottm of the BC blew out from hydraulic lock. JMHO.

Posted: 10/27/2004 3:02:19 PM EDT

[#4]

I'm guessing that the process started with the first round...

Posted: 10/27/2004 3:03:07 PM EDT

[#5]

Progressive stress damage.

Tap lightly on a window with a hammer. It won't break. Continue to tap, and eventually, it will.

You might not break through a cinder block wall with a sledgehammer on the first stroke, but
keep at it and you will get through.

CJ

Posted: 10/27/2004 3:03:38 PM EDT

[#6]

Something smells fishy.

I think it's a trap.

Posted: 10/27/2004 3:10:47 PM EDT

[#7]

Buffer tube filled with water and wouldnt let the bolt unlock?

Posted: 10/27/2004 3:12:30 PM EDT

[#8]

Posted: 10/27/2004 3:14:18 PM EDT

[#9]

Since we have only one data point for this "experiment" we can't tell if this was a fluke or not.
We need more data to answer this burning question... RedGoat you got 4-5 ARs we can borrow to answer your question, I promise to give them right back when I'm done.

Posted: 10/27/2004 3:15:08 PM EDT

[#10]

None of the above

It was not engineered to fire underwater ---
thats all.

Posted: 10/27/2004 3:17:47 PM EDT

[#11]

~~pics?~~
found the other thread

Posted: 10/27/2004 3:20:06 PM EDT

[#12]

I personall think "who gives a fuck". He fired it underwater, apparently it broke. I seen those gay army commercials that show guys popping out of the water ready to shoot. People do stupid shit. I have posted my mistakes on here. Glad he is okay and lesson learned. hopefully his example will show many people that have wonder such things, what happens and now no one will get hurt. Lay off the guy unless you are guilty of no stupidity ever.

Posted: 10/27/2004 3:24:25 PM EDT

[#13]

Got me thinking though....

If you have a muzzle condom on, and locked and loaded, how long can it be submerged before the barrel gets enough water into it to be a problem? (buffer has an O-Ring, so that should last longer, right?)

Posted: 10/27/2004 3:27:33 PM EDT

[#14]

Because God gives even idiots a second chance.

Posted: 10/27/2004 3:29:36 PM EDT

[#15]

He should check inside his barrel, maybe rounds didnt make it all the way out and progressivly backed up, I have seen it with sand.

Posted: 10/27/2004 3:31:59 PM EDT

[#16]

Quoted:
Got me thinking though....

If you have a muzzle condom on, and locked and loaded, how long can it be submerged before the barrel gets enough water into it to be a problem? (buffer has an O-Ring, so that should last longer, right?)

I dunno either.

If the chamber is closed, and muzzle covered?

Might take a while to leak enough.

How can the barrel fill with water if gases are being expelled in 1/4 sec intervals?

TRG

Posted: 10/27/2004 3:32:54 PM EDT

[#17]

Quoted:
I think it took that many rounds to pump enough water into the gas system. The bottm of the BC blew out from hydraulic lock. JMHO.

So a piston fired AK or DR200 would not have exploded?

TRG

Posted: 10/27/2004 3:34:05 PM EDT

[#18]

Quoted:
He should check inside his barrel, maybe rounds didnt make it all the way out and progressivly backed up, I have seen it with sand.

now, that might make sense if there was a delaye between 4 and 5.

4 did not exit, five struck it?

Why would 4 not exit if 1,2,3 did?

TRG

Posted: 10/27/2004 3:35:28 PM EDT

[#19]

Quoted:
Quoted:
Got me thinking though....

If you have a muzzle condom on, and locked and loaded, how long can it be submerged before the barrel gets enough water into it to be a problem? (buffer has an O-Ring, so that should last longer, right?)

I dunno either.

If the chamber is closed, and muzzle covered?

Might take a while to leak enough.

How can the barrel fill with water if gases are being expelled in 1/4 sec intervals?

TRG

If there is any air in the BBL it will blow

if it has no air at all --- it will fire but the presures are high , real high, you will get away with it ??? number of times then bad stuff will happen.

Posted: 10/27/2004 3:37:41 PM EDT

[#20]

Quoted:
Quoted:
I think it took that many rounds to pump enough water into the gas system. The bottm of the BC blew out from hydraulic lock. JMHO.

So a piston fired AK or DR200 would not have exploded?

TRG

In any event, I though the THEORY behind not firing rifles under water was that water in the barrel would act like a "plug" causing a blowout because the bullet couldn't move through the barrel fast enough and the gas pressure would blow back into the bolt/lower - not that water got into the gas tube.

Posted: 10/27/2004 3:39:04 PM EDT

[#21]

Quoted:
Quoted:
He should check inside his barrel, maybe rounds didnt make it all the way out and progressivly backed up, I have seen it with sand.

now, that might make sense if there was a delaye between 4 and 5.

4 did not exit, five struck it?

Why would 4 not exit if 1,2,3 did?

TRG

He hasnt replied to that thread in a while has he? We should ask him to check the inside of the barrel. I would say maybe even 1, 2, 3 didnt make it, just got stuck, increasingly closer to bore, then by last it got close enough and boom. I have seen Marine Corps saftey sheets that talk about up to 6-7 rounds with sand, and seen it happen once, but the guy only had 2 rounds stuck in barrel.

Posted: 10/27/2004 3:42:05 PM EDT

[#22]

Quoted:

if it has no air at all --- it will fire but the presures are high , real high, you will get away with it ??? number of times then bad stuff will happen.

Dude...are you on drugs this evening? What's the deal with your posts today?

Posted: 10/27/2004 3:46:49 PM EDT

[#23]

an ar ain't watertight folks.

even if the ejection port was closed initially, after the first attempt at achieving cyer-imortality, water rushed into the action immediatly following the first round having the spent case ejected.

'what' do you think happens as round number two gets chambered?

h2o gets chambered along with mr. bullet. not only that, in the time that the action is cycling some more h2o is working in from the muzzle. a just fired pipe is a low pressure zone.

in the span of time it took braniac to crank off 4 rounds there was sufficient water (a solid, at high velocities for all intents and purposes of this discussion) contained in the chamber/bore to cause the pressure to build to a point far exceeding even the safety factor built into working parts of the rifle.

my guess is that the overpressure caused catastropic failure of the bbl. extension's locking lugs and the overpressure condition of the rearward travelling bolt caused the carrier to split along the reief groove lines next to the cocking surface.

exhaust gases, at levels exceeding saami specifications, then drove the water in the action in the paths of least resistance. remember...air can be compressed rather easily into a much smaller volume. the same can not be said for water. it is more akin to hydraulic fluid in this application.

the hydraulic effect created by the pressurized water is what probably killed the aluminum parts and aggravated what have probably been an automatic magazine blowout.

Posted: 10/27/2004 3:48:06 PM EDT

[#24]

You can't "bumpfire" under water.

Think about it.

SGtar15

Posted: 10/27/2004 3:49:56 PM EDT

[#25]

Quoted:
Quoted:

if it has no air at all --- it will fire but the pressures are high , real high, you will get away with it ??? number of times then bad stuff will happen.

Dude...are you on drugs this evening? What's the deal with your posts today?

Repeating what I read in a an old guns and ammo mag

they shot a gun underwater and it functioned once -- showed signs of high pressure thats all

they said if it air had been in the bbl it would have blown up ...

Posted: 10/27/2004 3:50:24 PM EDT

[#26]

perhaps not, sgtar15.

but pulling the trigger fast will still set them damn near as fast as a slow rate of fire machinegun.

Posted: 10/27/2004 4:39:53 PM EDT

[#27]

Take a strong finger

Sgatr15

Posted: 10/27/2004 4:46:54 PM EDT

[#28]

lol!

put you finger in a sink full of water.

now...how fast can you pull an imaginary trigger?

that isn't gonna slow ya down much, if at all.

Posted: 10/27/2004 4:47:48 PM EDT

[#29]

Quoted:
I'm guessing that the process started with the first round...

I'm guessing the process started with a moron.

Posted: 10/27/2004 4:49:15 PM EDT

[#30]

Gun blowups resulting from bore obstructions invariably split the barrel but generally don’t blow the receiver apart. The damage I saw in the photos looks like a typical overpressure. This would suggest that a barrel full of water was the cause of the blowup. If your interested P O Ackley in his Handbook for Shooters & Reloaders describes experiments he did to see what it takes to blow up a gun using gross overloads of powder, bore obstructions and wrong cartridges. Great reading and photos, it puts to rest a lot of gun misconceptions on what does and does not blow up guns, I highly recommend reading it.

Rich V

Posted: 10/27/2004 4:51:53 PM EDT

[#31]

Quoted:
Buffer tube filled with water and wouldnt let the bolt unlock?

My first thought on seeing it.

Posted: 10/27/2004 5:04:31 PM EDT

[#32]

The buffer not moving has nothing to do with the blowup, it just turns a semi auto in to a bolt action. No change in chamber pressure.

Rich V

Posted: 10/28/2004 6:11:13 AM EDT

[#33]

Quoted:
Take a strong finger

Sgatr15

If I did not have pics in the thread to show what the result would be, I would try bumpfiring under water. If anything the minimal amount of water resistance would just make the gun bump slower.

TRG

Posted: 10/28/2004 6:13:36 AM EDT

[#34]

Quoted:
Quoted:
Take a strong finger

Sgatr15

If I did not have pics in the thread to show what the result would be, I would try bumpfiring under water. If anything the minimal amount of water resistance would just make the gun bump slower.

TRG

SInce the purpose of bump firing is the rifle "rocking" on the rear trigger finger I doubt it can be done.

Really. As for as a fast finger underwater...well, I never fired a gun underwater so wtf do I know.

Sgatr15

Posted: 10/28/2004 6:24:53 AM EDT

[#35]

Everyone here seems to have forgotten the scene in the movie where Mel Gibson shoots the bad guy under water with the AK....

It was on TV so I know it can be done