bullet spin

[knightsb]

I always thought rifling was done on black powder rifles that use round lead balls to increase accuracy.

As far as moving. If the ball is spinning on an axis that is in line with it's trajectory the seams would have the same bite all the way around. Not a physicist either. After farther thought I think the ones that move are not perfect bullet spins, probably off a little giving the seams on one side of the axis more exposure to the front of the ball thus more bite.

Sorry for highjacking the thread.

My DD has a natural bullet spin. Instead of coaching it out of her, we have been working with different grips (positions on the ball) to achieve greater movement.

 

[starsnuffer]

I always thought rifling was done on black powder rifles that use round lead balls to increase accuracy.


Sorry for highjacking the thread.

Black powder rifles (as opposed to muskets) use "minie balls" for projectiles. They're actually not balls, but shaped like the bullet you know. So yeah, you're right, the rifling is done to increase accuracy, but the balls aren't ball shaped The flat end is hollow or concave so the lead spreads out into the rifling to cause the thing to spin down the barrel, the two go hand in hand.

-W

 

[Bishop]

I do not understand how a pure bullet spin will move the ball at all. After all bullets are spun to increase accuracy and not move. I can see how an imperfect bullet spin would move the ball unpredictably, but not move very much.

Look up the term 'spin drift' as it relates to sniping and long range accuracy. It's accounted for in the shot calculations. At shorter ranges spin stabilises the bullet, at extended range it causes the bullet to drift in the direction of rotation.

My daughter throws a bullet spin fastball for speed and accuracy. A bullet spin fast ball is a good stepping stone to move on to a door knob rise, a curve and a screw ball. The finger and wrist action of the pitch is the same. Angle(s) of the wrist at release is the major change.

I don't know of any drop or change releases that are similar to the bullet release so it's building from scratch with those two pitches but it's been worth while for my daughter.

 

[Bishop]

Uh, oh. Starsnuffer and I went all gun geek again. Sorry.

 

[Carty]

I have to ask...doesnt spin drift come into effect on the downward trajectory of a bullet. IOW, as the axis of rotation becomes more vertical, the unequal pressure is on the left and right sides of the bullet causing the drift. Like a curve ball would spin. Just saying...

 

[Bishop]

Honestly, I don't know. But your explaination makes sense.

I didn't calculate it. I pulled it off the ballistic data card for the specific round when putting one down range. My basic understanding of physics agrees with your statement.

 

[T Red]

OK after a little research I can see how a bullet would drift, like Carty said as the bullet falls it does so nose up. Which would expose the lower side to more air. I still don't see how it would happen on a round ball in a short distance.

 

[Carty]

T Red, I dont see a bullet spin producing movement either, unless as you posted earlier, it isnt a perfect bullet spin.

 

[wannahit]

after viewing some of evans dvds and others who use the bullet spin, it doesnt appear you could incorpurate IR in that release, if you can please expain.