Take bore sighter off before shooting

[Stanze]

http://photos.yahoo.com/ph/edmondson_dave/slideshow?.dir=/.aed7scd&.src=mail&.tok=phInBrFB1TmQLX8B

[ohsmily]

I don't buy it. It looks like a staged, manufactured event. The banana effect doesn't seem like it would happen that dramatically because once any split was opened up for the gas to escape, it would go out that way and not continue to split down the barrel so far like that.

Mythbusters tackled this banana effect on the barrel myth in one episode, and they just couldn't do it. They tried welding a spike in the barrel, hammering rocks down it, and stuff bullets in it, all to no avail. The barrel bulged and sometimes split in one little place toward the front, but the banana effect didn't happen.

[PonyFiveO]

Mythbusters tackled this banana effect on the barrel myth in one episode, and they just couldn't do it. They tried welding a spike in the barrel, hammering rocks down it, and stuff bullets in it, all to no avail. The barrel bulged and sometimes split in one little place toward the front, but the banana effect didn't happen.

I believe the Mythbusters used a shotgun for their experiment, because that's what Elmer Fudd carried in the Bugs Bunny cartoons. I would think the pressures from the rifle round would be much greater than the shotgun shells.

Plausible?

[Recon]

Pressures in a 12-gauge shotgun are a tad lower than pistol pressures, and both are considerably lower than rifle pressures, especially Magnum calibers.

IIRC, the Mythbusters also tried it on their Carcano rifle and got nothing.

And I think there needs to be a Mythbusters segment on gun safety and showing what NOT to do with your guns. Like trying to chop through the barrel of a Browning M1919A4 with a katana.

[RANGER295]

[Pulsar]

It's real. I've seen it before. Though that barrel pealed back a lot more than the ones I've seen before. Actually in the classroom one of the insturctors has a barrel that is split into a perfect tripod from a boresighter being left in. He's planning on turning it into a lamp

[jtv3062]

http://www.thegunzone.com/m1akb.html http://www.thegunzone.com/m1akb/762r.html
take a look at these links to KB on a m1a (m14) the barrel split pretty good. myth busters could of used real tracers when shooting the gas tank instead of the air friction ones. they need to do more research on the myths they tests. there show is BUSTED.

[ohsmily]

http://www.thegunzone.com/m1akb.html http://www.thegunzone.com/m1akb/762r.html
take a look at these links to KB on a m1a (m14) the barrel split pretty good. myth busters could of used real tracers when shooting the gas tank instead of the air friction ones. they need to do more research on the myths they tests. there show is BUSTED.

The failures shown in those links you provided are COMPLETELY different from what was shown in the image in the first post. The first post, and the myth tackled on mythbusters is whether a "banana peel" effect will result starting from the MUZZLE from a blocked barrel. The images you showed were of a split/ruptured barrel and chamber. The failure was in the chamber. So, though those pics of the KB'ed M1a were interesting, they have no bearing on whether the myth is true or not about the banana peel effect at the muzzle on a gun barrel resulting from a blocked muzzle, etc.

[NeoWeird]

If you read the second link, the actual report of what happened, they say that it was caused not by excessive pressure (which would result from a plugged barrel) but by improperly manufactured steel that had microscopic cracks in it that slowly enlarged overtime until the stress was too much to take. Essentially the inside of the barrel had a crack running down it, like a perforated edge, and the entire length of the barrel was reaching critical dimensions. Once the shot was fired on the final round, the crack had expanded to the point where it seperated, and the still expanding gas and inertia in the barrel caused the crack to travel down the length of the barrel, resulting in the splitting of the receiver and stock.

Putting a boresight in a rifle would not have those 'advantages'. At best the Boresight would be launched down range with slight barrel damage at best. If the banna thing were true, then there wouldn't be any grenade launchers on the ends of some rifles, now would there?

[Josh]

The steel would fail more along its grain structure. The rifling isnt usually deep enough to come into play structurally. This is quite possible with a bore sighter and the proper type of cartridge.

Boy, we sure do have alot of engineers and experts on this topic. Man if mythbusters couldnt do it, it MUST be false.

Most likely the bullet went into the stem of the boresighter and the extra material that was jammed between the bullet and barrel was enough to cause the pressures to rise past the point of failure for the steel and then the whole thing just poped. Very similar to firing after a squib load. The end of the boresighter most likely poped off from the pressure and the bullet never even had a chance to make contact with that portion.

[Pokey]

A large part of the banana peel story goes back to Damascus barrels, which due to the methods of their creation, had weaknesses in many locations. I have seen Damascus barrels 'Elmer Fudd"-ed.

[jtv3062]

[dwtt]

I don't think that barrel was staged since an obstructed barrel can fail just like that picture shows. Here's a link to Blue Grass Armory's test of their .50cal Viper.

http://www.bluegrassarmory.com/Viper_HiSpeed.wmv

I bought a Viper and was told by the owner that they did these tests for the benefit of the military, it seems they were interested in procuring Vipers for use at one time.
There might be some mechanical engineers or metallurgists here, but they should know that in an obstructed barrel where the obstruction isn't fixed, like a welded plug, but is movable like a bore sighter, the hoop stress would be higher than the axial stress because of the stress concentration from the sharp corners of the grooves. But what do I know?

[Pulsar]

The failures shown in those links you provided are COMPLETELY different from what was shown in the image in the first post. The first post, and the myth tackled on mythbusters is whether a "banana peel" effect will result starting from the MUZZLE from a blocked barrel. The images you showed were of a split/ruptured barrel and chamber. The failure was in the chamber. So, though those pics of the KB'ed M1a were interesting, they have no bearing on whether the myth is true or not about the banana peel effect at the muzzle on a gun barrel resulting from a blocked muzzle, etc.

I'll say it again, I've seen barrels do that before, every one I've seen has resulted from a left in boresighter. Talk to any gunsmith who's been smithing for several years and he'll probably have a story or two about banana'd barrels.

Like I said earlier too, one of my teachers (still in gunsmithing school) has a barrel that banana'd into a perfect tripod, and he's planning on turning it into a lamp.

[Vigilante]

I've seen at least one barrel which had been split like that. This one was split in half, not quartered like the one in the picture. I guess my point is that it does happen. To idiots that is.