Forensic Gunsmith

[Killer]

Did your friend find out anything on this?

[vanmedic]

Bringing this old thread back up, had same thing happen with a Ruger M77 25.06, I can tell you from a bad experience, a .308 will bolt up in a 25.06, makes one heck of a boom, got splinters out of my face for 6 months, to beat all it was a bull barrel target model and the .308 projectile exited the barrel. Two guns on same bench is a mistake I will never make again.

[breadman]

had a Remington 700 25/06 few years back , bought some 20 year old custom factory ammo from a guy and fired a round and I could fell the preasure on my face luckly thr bolt held and no damage to me or the gun the primer pocket of the spent round was blowed out and burned up . sent the ammo ( all 9 boxes and the spent case to Remington for them to exam it . there findings were that the ammo had not been stored properly and that moisture had coroaded the primers , said that I was lucky it was a model 700 or the action would have failed and blew up . the gun was fine and still shot great. lesson learned store ammo in dry/cool space. Remington however did replace all boxes with new corelock ammo free of charge . didn't ask them to but it sure was nice of them.

[Pistol]

Did your friend find out anything on this?

Mismatched cartridge.
I'm a firearms examiner and consulted with him.

[softpoint]

Ammunition or barrel obstruction. The rifle looks like it actually performed as designed, the gas vented into the action, and the bolt stayed locked. Gas venting into the action will often split the stock on rifles. A guess would be ammunition, either a wrong caliber cartridge in the mix, or a dangerously high pressure load. Barrel obstructions most often split the barrel, or crack or split the front receiver ring, although too hard to tell with only a picture.

[Pushbutton2]

Ammunition or barrel obstruction. The rifle looks like it actually performed as designed, the gas vented into the action, and the bolt stayed locked. Gas venting into the action will often split the stock on rifles. A guess would be ammunition, either a wrong caliber cartridge in the mix, or a dangerously high pressure load. Barrel obstructions most often split the barrel, or crack or split the front receiver ring, although too hard to tell with only a picture.

See post #79

[Killer]

Mismatched cartridge.
I'm a firearms examiner and consulted with him.

So wrong caliber ammo?

[TXBadger]

Yikes, glad he's OK.

[Pistol]

Ammunition or barrel obstruction. The rifle looks like it actually performed as designed, the gas vented into the action, and the bolt stayed locked. Gas venting into the action will often split the stock on rifles. A guess would be ammunition, either a wrong caliber cartridge in the mix, or a dangerously high pressure load. Barrel obstructions most often split the barrel, or crack or split the front receiver ring, although too hard to tell with only a picture.

Good observations, Fred. Applying simple physics, gas pressure will always flow to the weakest area, a catastrophic failure will occur near the obstruction. (That's what we call this, a catastrophic failure).

In the case of a bore obstruction, the failure will be in the barrel where the obstruction occurs. The barrel is split, but when you examine the split itself, there will be a small area that points outward in a v and ^; that is usually (not always) where the obstruction was. Typically we see this in a ruptured barrel near the muzzle, as in shotguns that were jammed with mud during waterfowl hunting, or rifles that had a bore sight in the muzzle.

In a mismatched cartridge, many times the bullet will travel about 1/3 of the way down the barrel before becoming lodged (unless it's the right caliber). However, the gas pressure flows back to the cartridge case, which is not supported because it is the wrong size. The thin brass case will fail at the extractor groove, rupture the head off and the case body will swell, or fire form to the chamber. It will not come out of the gun easily. In a bolt action gun, the pressure will now cause the bolt to burst open, fracture the receiver and likely shatter any optics and stock. This is where the case head gets lost in the grass too.

As you can read in previous replies, it is a mistake many of us have made or know someone personally that has done it, and especially if you are shooting two different calibers at the same time.

I did it once early in my career. I fired a 7.62x39 cartridge in an Arma-Lite rifle chambered for 243. My mistake was because there was no visible caliber stamp, no magazine, and a flash hider obscured the diameter of the bore. I discovered the caliber when we pounded the bullet out and put a micrometer on it = 0.243. A call to Arma-Lite confirmed the gun was made in 243 and we finally found the caliber stamp hidden under the camo finish near the flash hider.

Cajun Blake nailed it.

[dustoffer]

One of the guys on the lease took his uncle to the range to familiarize him with the rifle prior to coming down for a hunt. Had 2 M77s on the bench, a 7 Mag and a .270. My buddy took the .270 to the truck and left Uncle Roger alone. Well, he managed to put the .270 round in the 7 Mag and bang!! I credit the M77 -- blew the floorplate off, but no injury to Uncle Roger except the a** chewing he got. Gunsmith checked the rifle out and only thing needed was the mag follower, spring, and floorplate. Here's the cartridge case:

[double bogey]

A gun exploding scares me to death. I hop I never experience it.

I have only had a rim failure in a 10-22 myself. Enough gas and powder escaped out of the action, and a hole in the rear of the receiver for cleaning from the chamber end, I can only imagine what it would be like to have a high powered rifle grenade a few inches from your face.

The failure in the 10 22 was from a dirty chamber that prevented the bolt from pushing the round all the way into the chamber. The 10 22 shouldn't allow the hammer to reach the firing pin in an out of battery condition. Mine couldn't have been more than .005 out (I tested with fired brass and feeler gauges in front of the bolt to confirm hammer strikes), but it was enough to let the rim rupture. I was doing a test to see how long I could run this gun until failure to feed or fire, or accuracy degraded. I was in the neighborhood of 1500 rounds when this occurred. I simply pushed the bullet from the barrel with a brass rod, cleaned the chamber and kept shooting. Accuracy never degraded, but I clean the chamber at least once a brick or so. The barrel doesn't have any appreciable leading. I discontinued the test due to desire to save my .22 stash during the Obama years.