finger in barrel- mythbusters on tv

[charlie]

The cable show Mythbusters had an intresting segment the other night.

What happens when one plugs the end of a gun barrel with his finger and pulls the trigger? Does the gun blow up leaving the hand unharmed like in the cartoons?

They fashinoned a fake hand out of ballistic gel and fake bones and pushed the index finger into a shotgun barrel. They fired the shotgun remotely. The hand was destroyed. The shotgun was unaffected.

They tried seveal variations of this. They plugged a rifle barrel at the muzzle and a shotgun as well. In both cases, the muzzle blew off and the barrel slighly bulged. In one case the shotgun barrel blew a hole behind the obstruction. What was impressive was that they were unable to get a barrel to spit into ribbons.

Seems to say a lot about modern firearms barrel strength, although they didn't try a double or triple charged round, the barrels seemed to hold up well.

They had a moulded gel human shaped figure against the shotgun butt and it appeared undamaged, implying that a shooter would be unhurt.

I still wouldn't want to have a barrel failure.

Has anyone on the forum had a barrel failure? What happened?


They also tested whether driving a pickup truck with the tailgate down saves gas. Suprisingly, it doesn't. They got better gas milage with the tailgate up.

[txinvestigator]

The cable show Mythbusters had an intresting segment the other night.

What happens when one plugs the end of a gun barrel with his finger and pulls the trigger? Does the gun blow up leaving the hand unharmed like in the cartoons?

They fashinoned a fake hand out of ballistic gel and fake bones and pushed the index finger into a shotgun barrel. They fired the shotgun remotely. The hand was destroyed. The shotgun was unaffected.

They tried seveal variations of this. They plugged a rifle barrel at the muzzle and a shotgun as well. In both cases, the muzzle blew off and the barrel slighly bulged. In one case the shotgun barrel blew a hole behind the obstruction. What was impressive was that they were unable to get a barrel to spit into ribbons.

Seems to say a lot about modern firearms barrel strength, although they didn't try a double or triple charged round, the barrels seemed to hold up well.

They had a moulded gel human shaped figure against the shotgun butt and it appeared undamaged, implying that a shooter would be unhurt.

I still wouldn't want to have a barrel failure.

Has anyone on the forum had a barrel failure? What happened?

Did you see the episode where they shot into a swimming pool to see how far under a person had to be to be safe? They also did the old 'if you shoot a bullet straight up it will come down and kill a person' myth also.

I really like the show. The debunked the myth about explosive decompression in aircraft also.

They also tested whether driving a pickup truck with the tailgate down saves gas. Suprisingly, it doesn't. They got better gas milage with the tailgate up.

A car magazine, I forget which one, did this years ago in a wind tunnel and with fuel rate measuring equipment on a track. They concluded that with the gate up, a bed or cushion of air is created in the bed. This allows air to flow smoothly over, around and past the vehicle.

With the gate down a back draft is created at the end of the bed, creating additional drag.

Did I say I love that show?

[Crossfire]

Did you see the episode where they shot into a swimming pool to see how far under a person had to be to be safe?

And what was the answer? I may need to know this someday!

[charlie]

I missed those.

It always seemed to me that if you shot a bullet straight up, it would reach its peak and fall at a speed somewhat below (due to drag) terminal velocity, which I think is around 180 mph.

I calculate that to be somewhat below 264 ft/second, which would hurt if it hit you, but I don't see it being fatal. A slow 38 spl is over 600 ft/sec.

What did they say?

Also, how far under water do you have to be? Guess it depends on the caliber and barrel length.

[Mithras61]

I missed those.

It always seemed to me that if you shot a bullet straight up, it would reach its peak and fall at a speed somewhat below (due to drag) terminal velocity, which I think is around 180 mph.

I calculate that to be somewhat below 264 ft/second, which would hurt if it hit you, but I don't see it being fatal. A slow 38 spl is over 600 ft/sec.

What did they say?

Also, how far under water do you have to be? Guess it depends on the caliber and barrel length.

For the shooting into a swimming pool, they concluded that a high-power round (basically anything from a modern weapon fell into this category) you would have to be under about 2.5' of water. For an older style weapon (like a musket) you would have to be under about 6' to 8' of water to be safe. It seems that the bullets from modern weaponry had problems with the transition from air to water and broke up pretty much on impact. You have to watch out, though, because if they put the gun under water and fill the barrel before firing, the bullet goes MUCH farther (it was from another episode, and if I recall the episode details correctly, it was about 16' from a 9mm).

The bullet into the air thing depends on the bullet going STRAIGHT up, because if it maintains a parabolic ballistic path, you're toast. If the parabolic ballistic path is NOT maintained, the bullet comes down fast enough to give you a good smack, but not even fast enough to break the skin in the majority of cases (I don't recall the speeds, but it was WELL below dangerous - I think it went about 6 inches into soft mud). They found the same thing for a penny (the old theoretical penny off the Empire State Building myth).

[txinvestigator]

A bullet shot exactly straight up will fall as Charlie described; however, if there is any angle and the barrel is not straight up, then the bullet will generally maintain enough velocity to be fatal.

The underwater thing depended on the caliber. It surprised me to learn that smaller calibers actually penetrated further than larger ones. I believe that about 2 to 3 feet under made you safe from most.

[Crossfire]

Well, now we know...

[kw5kw]

They also tested whether driving a pickup truck with the tailgate down saves gas. Suprisingly, it doesn't. They got better gas milage with the tailgate up.

This has actually been know for a long time in the auto industry, but... just try and convience "Bubba" and "Bubba's Uncle" of this.


http://www.cartalk.com/content/columns/ ... er/05.html
(ck the date on this first one... Oct. 5, 1997)

http://amos.indiana.edu/library/scripts/tailgate.html
http://www.bitware.com/5er/tailgate.htm
http://dailyfueleconomytip.com/2006/06/ ... te-up.html
http://ask.yahoo.com/20050427.html
http://www.hellerauto.com/faqs.htm


Russ

[cyphur]

I've seen a massive barrel failure on an M1A2 Abrams Main Battle Tank. I was on radio watch for the battalion(was in S3 at the time) and a Company Commander was making one of the last late night runs(around 3am) and the driver ran off the tank trail and into a ditch, but since the Captain didn't have a grip on the commander's stick, so the main gun tube didn't autoelevate to "keep on target". Consequently the main gun tube got buried in dirt, and they had to do a battlefield cleaning.

Apparently they missed something, b/c when they fired the first training sabot, it partially mushroomed the end of the 120mm gun tube. That tube is probably a full inch thick, at least - and its forged. Hearing that across the net @ 3am was rather amusing, to say the least.

They had to cut off the end of the barrel, and the Maintenance Chief decided to use it as a 40lb door stop/conversation piece.

[KBCraig]

They had to cut off the end of the barrel, and the Maintenance Chief decided to use it as a 40lb door stop/conversation piece.

"This here's my sawed-off Abrams!"

I guess that would screw up the optical collimator system, though, eh?

[bauerdj]

A bullet shot exactly straight up will fall as Charlie described; however, if there is any angle and the barrel is not straight up, then the bullet will generally maintain enough velocity to be fatal.

I can't quite figure out why this would be true. I would think as the barrel moved off of vertical the velocity would SLOWLY increase. I would think that at say 10 deg. off vertical there would only be a small increase in velocity and would not be much more likely to be fatal then true vertical.

I may be missing something that make this incorrect but if so I can't understand the physics involved.

Dave B.

[txinvestigator]

A bullet shot exactly straight up will fall as Charlie described; however, if there is any angle and the barrel is not straight up, then the bullet will generally maintain enough velocity to be fatal.

I can't quite figure out why this would be true. I would think as the barrel moved off of vertical the velocity would SLOWLY increase. I would think that at say 10 deg. off vertical there would only be a small increase in velocity and would not be much more likely to be fatal then true vertical.

I may be missing something that make this incorrect but if so I can't understand the physics involved.

Dave B.

Yeah, I shortened it and made it simpler than it is. I think the key is to know at what angle the bullet would lose fatal velocity before beginning its arc downward. I am not a physicist

Theoretically; A bullet fired at 90 degrees will actually lose all velocity before beginning to fall back to earth. Then it will only reach velocity from gravity. As the angle is decreased from 90 degrees, there is a point in which at the bullet will not lose enough velocity from being fired to cease being potentially fatal.

Does that make any sense?

[cyphur]

They had to cut off the end of the barrel, and the Maintenance Chief decided to use it as a 40lb door stop/conversation piece.

"This here's my sawed-off Abrams!"

I guess that would screw up the optical collimator system, though, eh?

Hahaha, yea. He didn't get to keep the green stuff.

[KBCraig]

Yeah, I shortened it and made it simpler than it is. I think the key is to know at what angle the bullet would lose fatal velocity before beginning its arc downward. I am not a physicist

Theoretically; A bullet fired at 90 degrees will actually lose all velocity before beginning to fall back to earth. Then it will only reach velocity from gravity. As the angle is decreased from 90 degrees, there is a point in which at the bullet will not lose enough velocity from being fired to cease being potentially fatal.

Does that make any sense?

I think the key is whether the bullet "noses over" in a ballistic arc.

A bullet fired vertically maintains its spin velocity even after it loses forward velocity. The gyroscopic effect keeps it stable, and it falls to earth base first, propelled only by gravity and limited by the aerodynamics of the blunt base.

But if it's fired at an angle far enough from vertical that it will continue its ballistic path point-first, it will be more deadly on impact.

The guys at Natick (small bullets) and Sill (big bullets) have mountains of data about this.

Kevin

[bauerdj]

Thanks TXI and KBC, makes sense what you both said. I would think both angle and cartridge load would have to be taken into account to determine energy level remaining (except at true vertical)

Dave B.