now thats what i call an earth shattering KABOOM

[Preacherman]

Just a thought - could this have been caused by a larger-than-caliber bullet in the Federal cartridge? I ask this because I've heard (on THR) of an instance where a single round of .308 was found in a box of Federal .243 ammo. If a round of (say) .338, or 8mm. Mauser, was inserted in the box, would it have been possible to chamber it, and then have the "swaging" effect of firing the round cause the explosion?

Still looking for explanations...

 

[mete]

Blues Bear, as a metallurgist I disagree. Barrels don't fail from "a steady increase in pressure" The pressure is the highest just as the bullet is about to leave the case then the pressure drops .An end of barrel obstruction causes a sudden increase in pressure which may split the barrel..This happened at the breech end of the barrel . We may eliminate fatigue since it's a new barrel and I doubt a barrel defect since it split into three parts. Perhaps a very fast powder,or detonation from reduced charge of very slow powder [it's a 300win], or wrong bullet [ a 338 ].Those would be my suspicions.

 

[Andrew Wyatt]

I'm assuming the flutes were cut on a CNC.


it's entirely possible the flites were cut too deep. This may have been the first barrel machined after the end mill was replaced, and the tool nose offsets may not have been corrected. if they're set for a worn tool, replacement with a new toool can mean the tool cuts deeper.

 

[borderguy]

I'd be giving both Sako and Federal a call. Then check the rest of the ammo to see if it's within spec.

 

[Mal H]

I'm sure Harry Tuttle is fine since the Sako and the ammo were not his. The report was originally posted on bpcr.net.

 

[rbrowning]

Dan Lilja describes a barrel failing like this if it is not properly stress relieved. I wonder what the heat treating that it actually saw was. Some micrographs of the crystaline structure should be interesting.

 

[molonlabe]

The steel needs microanalysis (as rbrowning suggested) it appears to be a defect in the barrel manufacturing and or the heat-treating process coupled with the barrel fluting. Without analysis you can’t say for certain.

It looks strangely familiar to this incident. Read the analysis link from this web page.

http://www.thegunzone.com/m1akb.html

 

[BluesBear]

The pressure is the highest just as the bullet is about to leave the case then the pressure drops

Pressure doesn't drop once the bullet leaves the case unless all the powder has been consumed. Which is the explaination of squib loads.
But since the powder is still burning more gasses are being created and therefore pressures are still rising.

If maximum pressure was created just as the bullet left the case then when the action blew open and the gasses were released, the bullet would essentially stop in it's tracks and remain in the barrel.

Also, if all of the powder was consumed before bullets leave the casing, there would be no need for those evil flash hiders and muzzle brakes would be inneffective.

 

[atek3]

First thing I said was, "Since when did Glock start making rifles?"

<ducks>


atek3

 

[Zach S]

I'm assuming the flutes were cut on a CNC.


it's entirely possible the flites were cut too deep. This may have been the first barrel machined after the end mill was replaced, and the tool nose offsets may not have been corrected. if they're set for a worn tool, replacement with a new toool can mean the tool cuts deeper.

I hadnt thought of that, but it is very possible. We threw quite a few engine blocks away when I worked at OMC because of simular situations...

 

[Guntalk]

Two words.

SHOOTING GLASSES!

If you forget them, borrow or buy some, or go home and get 'em.

Sheesh. Gives me the willies looking at those pix..

 

[Tinker]

I'd hate to differ with you Guntalk and don't want to dismiss the use of safety glasses, but that unfortunate shooter needed a Lexan blast shield in that case. Holy smokes, that is scary looking. I hope the shooter is OK.