What blew up my gun?

[jbs2014]

After seeing Rex Tibor's response to the Serbu .50 BMG detonation that nearly killed the shooter I started thinking of this thread. At one point in the video Rex mentioned something about even slight bore obstructions causing issues. Maybe that is what happened to the OPs rifle?

Thoughts

 

[Alex Wheeler]

Max pressure happens when the bullet is only a couple inches into the barrel. By the time it reaches the muzzle pressure has dropped considerably. I have seen brakes not bored out large enough for the bullet to pass through. They just blow off the muzzle. Even if there was an obstruction how much could a plastic sabot add? My bet is an over charge in powder or some degradation of the powder over time. One thing I agree on is theres no way an action should do that at 85k psi. We run into the 70s often.

 

[ButterBean]

Max pressure happens when the bullet is only a couple inches into the barrel. By the time it reaches the muzzle pressure has dropped considerably. I have seen brakes not bored out large enough for the bullet to pass through. They just blow off the muzzle. Even if there was an obstruction how much could a plastic sabot add? My bet is an over charge in powder or some degradation of the powder over time. One thing I agree on is theres no way an action should do that at 85k psi. We run into the 70s often.

X-2

 

[skipglo]

X-2

X-3....."An un-seen, special tool un-measureable invisible obstruction.....those are something we should be aware of, and order the SPECIAL TOOLS to see them....as soon as possible. As a matter of fact....gives me a business idea...I'm on it!!!

 

[Jim See]

Agree with Alex on this, has been more common recently with some brass manufacturers making case heads .175-.185" thick.
We could easily tell if this was the case having the barrel in hand and doing some measurements as well as inspecting the brass. Since this thread is 2 years old i doubt that will happen.

The failure point was the brass, it failed to contain the pressure, the reason it failed is unknown. I'm not sure you can put enough varget in a 22-250 to rupture a case head in a well assembled rifle. but an unsupported case head can rupture and cause this with a normal charge weight.

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Alex Wheeler

Well-Known Member

JoinedJul 5, 2017Messages1,247LocationMontana

• Feb 18, 2021
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• #285

Old thread but thats a heck of a chamfer at the back of the chamber, I wonder how much unsupported case head there was.

 

[Jim See]

Video I did on the subject.

 

[Wedgy]

As Mr 50 Cal noted the previous SLAP round had a considerably larger muzzle blast that those prior which is interesting, maybe the day grew hotter, rounds laying in the sun, etc.
As soon as I see a plastic picnic table instead of a shooting bench I have already made my decision on this youtube expert as far as learning versus entertainment.

 

[Hard rock]

As Mr 50 Cal noted the previous SLAP round had a considerably larger muzzle blast that those prior which is interesting, maybe the day grew hotter, rounds laying in the sun, etc.
As soon as I see a plastic picnic table instead of a shooting bench I have already made my decision on this youtube expert as far as learning versus entertainment.

Blow Ups There are many things which cause a rifle to blow up,but in almost every case it is something the shooter especially the handloader , has done . Common causesof blown up rifles when using factory ammo are obstructions in the barrel, opening the bolt to soon after a misfire which instead of of a misfire may be a hangfire ; extracting a loaded cartridge leaving the bullet in the barrel, then loading another cartridge behind it. There are a great number of blowups caused by improper handloading.The majority of handloaders use powder measures and powder measures are not infallible , although they are nearly perfect mechanically .Quite often a
powder measure will hold up part of a charge thus creating a reduced charge, then this partial charge which is held in thecc can we measure will be dropped into the case with the next full charge , thus creating a very badly over loaded cartridge. This trouble does not occur with small capacity cartridges as much as large capacity cartridges which are being loaded with relatively fast powder. It can happen with very badly overbore cartridges, which, even with the full powder charge , still have a relatively large air space. When such cartridges are charged with powder, it is well to look into each cartridge case after the powder is put in , to observe whether the powder charge is near the proper level. Another common causeof accidents is getting powders mixed . Many blow ups have occurred because a faster powder was accidentally substitutedfor slow burning powder . Cartridges with extremely short necks must be checked very carefully after the bullet has been seated , if a case with thin brass is sized in a sizing die which is normal it is possible the neck will not be tight enough to hol the bullet firmly , and when a loaded cartridge with a bullet seated in it which is not being held tightly is fed into the barrel , it is possible for the bullet to be pushed back into the case. Thus creates a extremely dangerous condition when the cartridge is fired . This trouble does not occur with factory cartridges in which the cases are crimped . Another blow up reduced charges in badly over bore cartridges . Handloaders have a hot-rodding - tendacy complex. This kind of handloader cannot find interesting loads listed in the various manuals except the hottest ones . So they start out using maximum loadsin spite of the warnings often this practice results in trouble. By Parker o. Ackley sorry for such a long post hope it helps

 

[North Idaho Hunter]

Look at the heavy chamfer on the end of the chamber - no case head support.....BOOM!

EDIT: jim beat me to it!

 

[Hard rock]

Look at the heavy chamfer on the end of the chamber - no case head support.....BOOM!

EDIT: jim beat me to it!

What could cause the heavy chamfer and how long would it have been like that beffore the gun blew up

 

[Jim See]

What could cause the heavy chamfer and how long would it have been like that beffore the gun blew up

The gun blew up because of a case head rupture, caused by either a 90,000 psi load, or an unsuported case. the chamfer being excessive supports less of the case head. watch the videos above if you need clarification. A normal load can rupture if the case head is unsupported, it may hold for many pieces of brass until that one piece that is comprimised in some way gets run thru the rifle.