Guns are dangerous. Federal AE223BK Kaboom.

[R.Miksits]

I thought Ned's pics showed that an OOB fire is largely imposible? Light Dimples are from the intertia of the firing pin coming forward after the bolt is closed, right?

Just a general question, for the OOB theory to be correct, the gun would have had to double, correct? So you have a gun that doubled, then with an OOB occurance at the same time? That is some pretty slim odds, eh? Versus the chance of an overcharge.

Typo

Supposed to read "I canT"

stupid keyboard

[Molon]

Sorry I used the wrong nomenclature, . . .


You allude to being some sort of expert on the subject, yet you confuse the most basic of terms.




. . . the point I was making was that the powder may be SIMILAR, but it IS NOT the same as H335, so your pressure chart is just a guess.

Reread your own words that I quoted in my previous post because you made absolutely no such point and the pressure chart is not "just a guess." It's a demonstration that the 5.56mm round can be loaded beyond "proof loads" with powders typically used for the round, as you stated that it couldn't be.



Even if it is correct, 80K chamber pressure should NOT blow the brass like in the pic.

Again, the 80K was just a demonstration that the cartridge can be loaded beyond proof loads of 70K that you stated it couldn't be. The cartridge could still hold more powder than the example I gave and with that the pressures could rise well above the 80K.



You are basing your pressure data on SAAMI CHAMBER pressure, not NATO spec,

Wrong. The parameters of the program were adjusted to match the findings of a Colt NATO chambered barrel.



which is measured at the CASE MOUTH, and can make a bunch of difference in CHAMBER pressure, as much as 20K psi, if I remember correctly.

You don't remember correctly. The often quoted figure of 15,000 PSI is for a mil-spec pressure round fired in a SAAMI chamber, not for the difference between the two measuring positions.




Our NORMAL 5.56 mm NATO-spec loads could average over 75,000 psi CHAMBER pressure, every time you pull the trigger.

Complete BS and of course you offer absolutely no scientific data to support that statement.




I'd guess the Armalite pic is of a reload with the wrong powder,
like Mr. Christianson's pistol powder example cited above.


And a guess is all it is since you have no proof to support the statement and of course you completely ignore the fact that the Armalite pics look exactly like those of Derek Connor's.





PITA, ain't I ?

No, you just post BS in a technical forum with absolutely no credible data to support it.

.....

[ZDL]

Sorry I used the wrong nomenclature, the point I was making was that the powder may be SIMILAR, but it IS NOT the same as H335, so your pressure chart is just a guess.

Even if it is correct, 80K chamber pressure should NOT blow the brass like in the pic.

You are basing your pressure data on SAAMI CHAMBER pressure, not NATO spec, which is measured at the CASE MOUTH, and can make a bunch of difference in CHAMBER pressure, as much as 20K psi, if I remember correctly.

Our NORMAL 5.56 mm NATO-spec loads could average over 75,000 psi CHAMBER pressure, every time you pull the trigger.

I'd guess the Armalite pic is of a reload with the wrong powder, like Mr. Christianson's pistol powder example cited above.

Again, if the ammo shot by the OP WAS a reload, all bets are off, but if it was factory ammo, I think other factors contributed to the problem.

PITA, ain't I ?

POST YOUR CREDENTIALS PLEASE!

[FromMyColdDeadHand]

Do I have a red deficiency, or is that red text really hard to read?

[ddemis]

SQUIB!

[Jay Cunningham]

Let's minimize the drift and stay on-topic.

[coldblue]

When I have seen brass fail in this manner (mabe a dozen times while in the marine Corps), it was always the result of a barrel obstruction--namely a round lodged in the bore--the result of a squib load, contaminated powder, no powder, etc. In the Service, you learn your malfunction drill so well that if in the middle of a rapid fire magazine you pull the trigger and nothing happens, you instinctively pull back on the charging handle and chamber another round and pull the trigger again, zip, zip, zip in about a second, never thinking about why the action had just failed to function normally. Then you drop the hammer onthe round you just chambered and kaboom!
Interestingly, this most often occured with L110 Tracer Ammo which had been spread-loaded with ball ammo in magazines. Had similar events with 7.62 linked ammo with ball rounds marked say WCC 71 linked 4:1 with tracers marked REM 62. This was the result of us (USMC) buying old lots of tracer ammo packed in 20-round boxes intended for the M14 Rifle from the Army "on the cheap", then inserting them into an ammo line making belted ammo for the M60.
A squib round may lodge anywhere in the bore from just outside the chamber (worst case) to down towards the muzzle (not so bad but still catastropic). This is nothing new or unique to the AR.
I remember in the olden days the FBI's spec for their revolver barels required S&W to use a bore design that if a squb load lodged a bullet in the bore but did not lock-up the cylinder (i.e., somewhere in the rifling), then the shooter could "safely" fire a second round in an emergebcy situation.
Bottom line is the AR chamber does not fully support the case head's web so as to help in reliable feeding from the magazine. So when you pop the cap on 50,000 pounds of presure something is going to give--and that is the area of brass not supported in the chamber.

[boltcatch]

Just keep in mind that the parameters of the program must be adjusted to match actual measured findings for it's projections to be accurate.

No shit... For all but one of my loads, given the correct inputs it is uncannily accurate. But for one, it is a couple hundred fps off and, by the looks of it, a few thousand PSI under. It needs a chrono and more than one loading manual to really be effective.

[Derek_Connor]

Update:

Federal picked up the 920 rounds I had left for this LOT from my house yesterday.

I included the defective case w/it.

They informed me they would be sending me out a replacement 1k Case of ammo. Unknown ETA.

Gun is back together, haven't had a chance to shoot it yet though.

[Thomas M-4]

Update:

Federal picked up the 920 rounds I had left for this LOT from my house yesterday.

I included the defective case w/it.

They informed me they would be sending me out a replacement 1k Case of ammo. Unknown ETA.

Gun is back together, haven't had a chance to shoot it yet though.

How was the barrel extension was it gtg ?
Glad to hear that federal worked with you on the ammo.