Bullet Flight
12-23-2005, 07:13 PM
#1
Thread Starter
Join Date: Jan 2005
Location: Lafayette, IN
Posts: 473
Bullet Flight
Got a question for you bullet experts. My brother comes into the room and tells me that a friend of his (who I know, not one of those "my best friend's brother's girlfriend's second cousin" deals) told him that he saw high-speed film or something similar of an AK-47 bulletin flight. Supposedly the bullet spins on a vertical axis instead of a horizontal one. I'm saying "bull", no way or at least so highly unlikely, something's wrong with the gun. Who's right?
12-23-2005, 08:14 PM
#2
Join Date: Dec 2003
Location: S Texas
Posts: 1,037
RE: Bullet Flight
Spins on a vertical axis? Do you mean like tumbling end over end? No way, unless the bullet was fired in a smoothbore, or struck something. Tumbling or keyholeing isn't terribly conduceive to accuracy.
12-23-2005, 08:24 PM
#3
Join Date: Sep 2005
Location: Big Sky Country
Posts: 100
RE: Bullet Flight
A bullet does not climb. It comes out in a (horizontal) straight line at whatever axis the barrel is at and drops from gravity and loss of velocity. Maybe the bullet spin is vertical, but the bullet isn't. Airplanes climb, bullets drop. 
MV out!
MV out!
12-23-2005, 09:16 PM
#4
Join Date: Feb 2003
Location: Blissfield MI USA
Posts: 5,293
RE: Bullet Flight
I had an AK that key hold bullets quite often, it was a complete peice of crap in the accuracy department. Tumbling in flight can happen though, it's for sure not something you want if you want any kind of accuracy. Most likely the barrel was damaged or had too little of a twist rate for the weight bullet being used.
Paul
Paul
12-25-2005, 12:10 AM
#5
Join Date: Aug 2004
Location:
Posts: 173
RE: Bullet Flight
I may be wrong on this one but I've never known a bullet to actually tumble end over end. If the rifling in a particular firearm is damaged or the bore has become smooth then the bullet may not stabalize and will probably wobble somewhat like a badly thrown football. Instead of a tight spiral you get that erratic wobble causing a tear in targets instead of a nice round hole.
Someone please correct me if I'm wrong.
Someone please correct me if I'm wrong.
12-25-2005, 08:48 AM
#6
Giant Nontypical
Join Date: Feb 2003
Location: Texas - BUT NOW in Madison County, NY
Posts: 6,270
RE: Bullet Flight
IF the spin rate imparted by the rifling is adequate to stabilize the bullet, and no forces interfere with the bullet after it leaves the muzzle, the bullet rotates on the axis of a line through the center of the bullet's point out through the center of its base.
Whether a bullet rises or falls in relation to the earth is determined by the angle of departure, ie. whether the bore is pointing up, down or parallel with the surface of the earth at the instant the bullet exits the muzzle.
Unless the line of the bore is perfectly parallel to the force of gravity (pointed straight up or straight down), the bulletstartfalling below the line of the bore immediately upon exiting the muzzle - it cannot climb, as unlike an aircraft, bullets have no "lift". So after leaving the muzzle, there are only two aerodymanic forces acting upon the bullet - drag, which slows it, and gravity, which pulls it down.
If you fire a bullet perfectly parallel with the surface of the earth, and drop another bullet from the height of the gun's muzzle at the same instant, both bullets will hit the earth at the same instant-one right under the muzzle, and the fired one some distance downrange. How fardownrange the fired bullet will travel before hitting the earth is determined by its muzzle velocity and its ballistic coefficient (how quickly air resistance makes it lose forward velocity). This is why faster bullets shoot "flatter" than slow ones.
Whether a bullet rises or falls in relation to the earth is determined by the angle of departure, ie. whether the bore is pointing up, down or parallel with the surface of the earth at the instant the bullet exits the muzzle.
Unless the line of the bore is perfectly parallel to the force of gravity (pointed straight up or straight down), the bulletstartfalling below the line of the bore immediately upon exiting the muzzle - it cannot climb, as unlike an aircraft, bullets have no "lift". So after leaving the muzzle, there are only two aerodymanic forces acting upon the bullet - drag, which slows it, and gravity, which pulls it down.
If you fire a bullet perfectly parallel with the surface of the earth, and drop another bullet from the height of the gun's muzzle at the same instant, both bullets will hit the earth at the same instant-one right under the muzzle, and the fired one some distance downrange. How fardownrange the fired bullet will travel before hitting the earth is determined by its muzzle velocity and its ballistic coefficient (how quickly air resistance makes it lose forward velocity). This is why faster bullets shoot "flatter" than slow ones.
12-25-2005, 11:14 AM
#7
Senior Member
Join Date: Jan 2004
Location:
Posts: 1,813
RE: Bullet Flight
I have "never" seen a slow speed film showing a bullet tumbling in flight, but i have personally shot, and seen targets that were shot, that the bullet hit sideways....
My BIL had a 22lr H&R revolver that no matter what brand of ammo you shot in it, the bullets always hit sideways, and you better be CLOSE to even hit acardboard box to see that!
The gun was VERY old and completely worn out! I doupt it was even safe to fire, but we were quite young, and you know how young folk are....
Drilling Man
My BIL had a 22lr H&R revolver that no matter what brand of ammo you shot in it, the bullets always hit sideways, and you better be CLOSE to even hit acardboard box to see that!
The gun was VERY old and completely worn out! I doupt it was even safe to fire, but we were quite young, and you know how young folk are....
Drilling Man
