Why is rifling twists always to the right? Is it because the way machinery is set up to spin clockwise when compressing? My questioning is because everything in the northern hemisphere naturally spins counter clockwise, draining water, tornadoes, ect

[Michael Christensen]

Why is rifling twists always to the right? Is it because the way machinery is set up to spin clockwise when compressing? My questioning is because everything in the northern hemisphere naturally spins counter clockwise, draining water, tornadoes, ect. So wouldn't a bullet that was rifled to spin counter clockwise be more accurate at longer ranges than a bullet that spins clockwise in the northern hemisphere? Because of the bullets ability to possibly maintain the twist longer than a bullet would if it spins clockwise?

[JM]

Good question...hopefully someone on here knows more than me because I'm interested now. Not all guns have rifling going the same way. Yes, the vast majority of guns will spin bullets clockwise, but there are some that spin counter-clockwise(can't think of any off the top of my head though). I think the biggest reason most bullets spin clockwise is because of the popularity and machinery used to make them(same tool manufacturers for multiple gun makers). I think the spin rate/twist rate is the only real thing to worry about. I can't think of a scenario when the direction of spin would matter.

[jcarlin]

I don't know, I know there are some LH twist barrels out there. This just came up at my local gun shop. He'd gotten some of the polycase ammo in. I questioned the same thing only because the bullets sure looked like they were designed in such a way to impart spin (in the LH direction oddly enough) and I wondered if they'd perform the same in LH and RH.

[jcarlin]

Somehow I mentally skipped over the coriolis effect as part of the question. Maybe a physicist will chime in but I don't believe that:

1-The coriolis effect is strong enough to have much impact on a dense projectile spinning at most for a couple of seconds.

2-That the premise that RH is better in the northern hemisphere makes sense unless you were shooting in a downward direction. Even if so, then
Australia would probably be the odd ally that was running M-4s with LH twist.

[huntfishtrap]

I can usually BS my way through an explanation well enough to sound like I know what I'm talking about, but for once even I'm at a loss for words. I have absolutely no idea. Even worse, now I'm curious about it, too. Lol I have never thought about that before, and I've never heard anyone ask that question. The direction of rifling is just one of those things you take for granted. I do know that when it comes to helical fletchings on arrows (which act to spin the arrow in the same manner that rifling spins a bullet), it doesn't matter if you have a right helical or a left helical. Both will stabilize the arrow identically, assuming all other factors are equal. To me, it would stand to reason that rifling would be the same - any difference between RH or LH twist would be so small as to be imperceptible. But I'm no physicist.

As to why most barrels - but not all - are RH twist, I don't know. I would assume that it has something to do with standardization of machinery, as JM said, but that's just a guess.

[JM]

Somehow I mentally skipped over the coriolis effect as part of the question. Maybe a physicist will chime in but I don't believe that:

1-The coriolis effect is strong enough to have much impact on a dense projectile spinning at most for a couple of seconds.

2-That the premise that RH is better in the northern hemisphere makes sense unless you were shooting in a downward direction. Even if so, then
Australia would probably be the odd ally that was running M-4s with LH twist.

Wind direction and speed will change multiple times during a shot, so I wouldn't worry about stuff like the coriolis effect since wind will have a greater effect on the bullet.

[Okwaho]

That might be a good question for Field and Stream's "Ask Petzal."

[charlie elk]

According to numerous articles written in NRA publications, there is no real reason--except for tradition.
There is some historical evidence that the Brits believed left-handed twist imparts slight leftward bullet drift which would compensate for a right-handed shooter's trigger pull.
After the revolutionary war, Americans wanted to be and show they were independent of Britain. Webster expressed independence with the American version of English while writing his Webster dictionary. He is the one responsible for dropping the unnecessary U's and changing S's and C's around. The American gun manufacturer's changed the rifling twist to the right, clockwise and since then that's the way they've always done it.
To make this easy to remember, if you buy a rifle made in a country where they drive on the wrong side the road the rifling will likely turn to the left. If you purchase the rifle made where they drive on the right side of the road, the rifling will turn right.

[charlie elk]

That might be a good question for Field and Stream's "Ask Petzal."

Hmm, this is OL, John Snow will have his feelings hurt with that suggestion. So I guess you'll not be winning any of John's contests.

[charlie elk]

I can usually BS my way through an explanation well enough to sound like I know what I'm talking about, but for once even I'm at a loss for words. I have absolutely no idea. Even worse, now I'm curious about it, too. Lol I have never thought about that before, and I've never heard anyone ask that question. The direction of rifling is just one of those things you take for granted. I do know that when it comes to helical fletchings on arrows (which act to spin the arrow in the same manner that rifling spins a bullet), it doesn't matter if you have a right helical or a left helical. Both will stabilize the arrow identically, assuming all other factors are equal. To me, it would stand to reason that rifling would be the same - any difference between RH or LH twist would be so small as to be imperceptible. But I'm no physicist.

As to why most barrels - but not all - are RH twist, I don't know. I would assume that it has something to do with standardization of machinery, as JM said, but that's just a guess.

Are you saying the beginning of that answer just might be the most truthful you have ever written?

[charlie elk]

Somehow I mentally skipped over the coriolis effect as part of the question. Maybe a physicist will chime in but I don't believe that:

1-The coriolis effect is strong enough to have much impact on a dense projectile spinning at most for a couple of seconds.

2-That the premise that RH is better in the northern hemisphere makes sense unless you were shooting in a downward direction. Even if so, then
Australia would probably be the odd ally that was running M-4s with LH twist.

The Coriolis effect is an example of overthinking things like this.

[Michael Christensen]

Just read in some places that the Coriolis Effect will not effect a bullets flight because it is to small and the flight duration is to short.

[huntfishtrap]

I can usually BS my way through an explanation well enough to sound like I know what I'm talking about, but for once even I'm at a loss for words. I have absolutely no idea. Even worse, now I'm curious about it, too. Lol I have never thought about that before, and I've never heard anyone ask that question. The direction of rifling is just one of those things you take for granted. I do know that when it comes to helical fletchings on arrows (which act to spin the arrow in the same manner that rifling spins a bullet), it doesn't matter if you have a right helical or a left helical. Both will stabilize the arrow identically, assuming all other factors are equal. To me, it would stand to reason that rifling would be the same - any difference between RH or LH twist would be so small as to be imperceptible. But I'm no physicist.

As to why most barrels - but not all - are RH twist, I don't know. I would assume that it has something to do with standardization of machinery, as JM said, but that's just a guess.

It's possible, charlie. Out of the mouths of babes and fools... ;-D

[huntfishtrap]

That might be a good question for Field and Stream's "Ask Petzal."

One question, Tiough - what did F&S give you in exchange for that endorsement? ;-)

[huntfishtrap]

According to numerous articles written in NRA publications, there is no real reason--except for tradition.
There is some historical evidence that the Brits believed left-handed twist imparts slight leftward bullet drift which would compensate for a right-handed shooter's trigger pull.
After the revolutionary war, Americans wanted to be and show they were independent of Britain. Webster expressed independence with the American version of English while writing his Webster dictionary. He is the one responsible for dropping the unnecessary U's and changing S's and C's around. The American gun manufacturer's changed the rifling twist to the right, clockwise and since then that's the way they've always done it.
To make this easy to remember, if you buy a rifle made in a country where they drive on the wrong side the road the rifling will likely turn to the left. If you purchase the rifle made where they drive on the right side of the road, the rifling will turn right.

Very interesting. Didn't know most of that.