How to blowup your rifle

[Pdvdh]

We've tested 700 actions to 175,000psi and the barrel spun off fine. Turned a .243 Win into a belted mag by doing so.

Screwed it back on and went to 210,000psi and then the action did end up in 2 pieces.

A 3 grain over load will not cause what the OP experienced in my opinion.

Have no idea what adam32 does for a living, or for entertainment, but this sounds like fun testing for anyone interested in Rem700 strength.

175,000psi expanded the 243Win case head where unsupported by the barrel every bit as much as the OPs case head from this description.

At 175,000psi, no problems removing the barrel from the Rem700 action either.

Running cartridges at 60-65,000psi leaves plenty of breathing room before Rem700 action/barrel blowup.

It appears something very extraordinary transpired when this cartridge was fired. Big time.

Permanent barrel deformation will tell much more about peak pressure levels than brass casing expansion. If the chamber is swelled, we then know peak pressure exceeded the elasticity limit of the steel the barrel was made of. A Remington engineer could figure that pressure level in short order. That would establish the minimum pressure. But not the actual pressure developed.

If the barrel chamber is bulged, I'd start to wonder if a faster burning powder found its way into the casing. I knew a guy did that with a Rem700 .243 Win varmint weight rifle in the early 1970s. He said he saw blue streaks of smoke race toward his target but no bullets ever impacted his target. He kept this up for several rounds trying to figure out what was going on before the action locked up tight.

Repairing gunsmith told him the cutting gasses which escaped out the case head had welded his bolt to the barrel and/or action.

Gunsmith got the rifle functioning again, but we were teenagers and didn't know what all was involved/replaced. His gun worked again and he was happy again.

This guy was known to do some pretty crazy stuff. In this instance, he had just begun reloading for his rifle, and he thought the Lee volumetric powder measures could be used with any gun powder. He had already been reloading shotgun shells. Cost him some money to learn the Lee volumetric powder cups were not one size fits all powders.

And I'm not making this up. This guy died in his mid30s. A shortened life, not from bad reloads - but similarly poor knowledge/understanding caused his premature death.

 

[Scooterbum]

I asked wink what other loads he prepared during that session, but rec'd no response. Perhaps wrong powder.

 

[CTK]

Some barrel makers will not make a stainless barrel below a certain contour. Some have outside diameter to bore minimums. Some do not care and will make pencil thin barrels in stainless. I believe the issue is cold weather. Likely all these guys are engineers. Is this variable levels of company risk tolerance or a difference in scientific oppinion?

 

[bigngreen]

One thing that one has to remember is this is a RUM diameter case so taking it to nuclear level had a pile more bolt thrust and much less meat around the shank part of the barrel.
The bore is definitely fouled but I'm trying to figure out a way to measure the bore and see if I can put a number to it, the fouling is significantly rough so I don't think slugging will work till it's cleaned.
Trying to get good borescoped pics is hard but I'm trying to get decent quality pics through the Hawkeye, the copper is chunky in some places on the pressure side of the lands and I'm trying to get a decent pic of that also copper in the grooves.
I see no evidence of anything in the bore, no gouging or anything odd.
Lots of copper and carbon fouling starting a couple inches in, heavy in the middle then clearing up in the last few inches and more normal looking.
No carbon ring or anything in the neck.

 

[JDD]

did not break

Looks like low temperature embrittlement to me. It broke at the receiver which does not get much heat from each firing and cools down quickly. Pronounced embrittlement occurs at -40F but is still a factor at -15F. Barrels and receivers are cold worked in the first place to make them hard but this also makes the steel brittle. Low temperature embrittlement does not affect the ultimate strength of steel but makes it susceptible shock loading, like igniting 86.8 grains of Retumbo behind a 230 grain bullet. Look it up "Low Temperature Embrittlement."[/QUOT

It did not break bolt pulled off and gunsmith could not unstick it . Si he cut it with a band saw!

 

[Scooterbum]

Of course the ,470 class chamber wall will also exhibit greater endurance than these outsizers.

 

[bigngreen]

Primer hole on the high pressure case is now .106!
The rim of the case was actually extruded forward into the groove, nearly obliterating the lettering.
The more I measure the more I'm thankful no one was hurt!

 

[bigngreen]

I've been trying to find the psi where cartridge brass suffers plastic deformation, that would at least give us an idea of a min pressure this reached. It also seems to me this would have taken some time under pressure as well not just a spike.

 

[Scooterbum]

U might check the depth to the lug abuttments also.

 

[Scooterbum]

I am wondering if the base extruded into unsupported prior to primer leaving.

 

[WildRose]

Me either. In the first place, that's dishonest. I wouldn't want to do any business with someone like that. In the second place, the manufacturer isn't that stupid.

I'm pretty sure that as soon as they see the bandsaw cut they're going to say, "you're out of your damned mind if you think we're going to warranty that".

 

[WildRose]

Dude, just send it back to Remington with the fired case. They don't know if it was factory or handloads. You'd be surprised that they would probably replace the barreled action. Always deal with the manufacturer first. They don't want the liability. It would cost them a couple hundreed dollars for a barreled action. They may offer to replace the barreled action for you cheap if they don't cover it fully. !!!

I'm reminded of the old saying, "You only get one chance to make a first impression".

Buddy, you blew it.

 

[Winkfish]

For the reloading of these cases Since there were so few I just hand cleaned them and whipped them off. There were no other project in progress at the time of loading and the only powder that was open was the Retumbo.

BignGreen if there is any value or it makes your assessment easier please feel free to do what you need to on the barrel. If that means cutting it open by all means do so.

Based on your analysis to date it appears that any and all pieces will be wall art and I will not be putting them back into another action.

I take personal responsibility for the outcome of my load development. I wouldn't be comfortable sending it into Remington without full disclosure that the failure resulted in part due to a hand load and that factory ammunition had not been in the rifle.

Thank you all for your continued input and analysis.

 

[charlie 7]

Winkfish

I've read the whole thread and I am convinced that the engineers at Remington did a very good job designing your gun.

I don't think that the fouling of the barrel is the culprit, I think the whole event took place while the projectile was still in the chamber as once the bullet travels down the bore pressure drops dramatically.

The unusual location of the case separation stretch mark as seen in post #50 points to the lubricant in the chamber or on the case.
Good gun design !!! as the lugs sustained the whole brunt of the charge with a lubricated (well, half of it) case in the chamber.

I suspect that the case was loaded for the 190gr projectile and when 230gr was seated to the same COL, the projectile reduced further the powder space sending the pressure higher still. There is 180 thou difference in length between those two projectiles.

On your original photo in post #1 the bolt head bears hammering marks on its lip, why did you hammer there.