Why is right hand twist so common?

In the Northern Hemisphere? Doesn't a left hand twist offer advantages at distance?

Cause most barrel cutters are right handed? Perhaps lathes or hammer forges run right handed?
Good question!
Do toilets swirl backwards in Australia?
Yes, I am drinking...

As a matter of fact, toilets in the Southern hemisphere do swirl the other direction.

Yep. Not to mention recoil index's into you and not away from you, if you are a right handed shooter, for higher caliber rifles.

How would it?

Spin drift working against coriolis effect and not with it.

Correct, a left hand twist would help at your much longer ranges to reduce coriolis, and I think reduce spin drift.

That's the impression I get. So why aren't the barrel makers on the top half of the world getting this right? At some point, they had to make tools or upgrade them. Seems like a good time to switch over or at least add the option.

WRONG!

How's it going to work against coriolis. If shooting south to north you're looking at a target that is moving to the right. If you're shooting north to south you're looking at a target that is moving to the left. West to east, target is moving away, east to west, target moving closer. I don't even figure it in shooting a mile, I think the wind is a bigger factor to be concerned with.

Spin drift? One time has it ever come into play for me. Zero wind, 178 gr out of a .308, 800, 900, 1000 yards, watched the bullet drift right of the target at 800, with a solid zero and not a leaf flickering. Rare conditions.

Just my opinion.


I did hear a tale of a LH twist barrel that was RH threaded into the action. The barrel unscrewed itself from the action. Not totally, but did daylight barrel to action.

Spin is spin, be it left rotation or right rotation. How's it going to reduce drift?

JG, go into your ballistics ap. Run the numbers on a load to a thousand yards, with no wind. The drift shown is your spin drift, right? Now edit the firearm to have a left twist, and run the same load with no wind. What does your spin drift show now?

With no wind, I get no lateral movement left or right twist...

Turn your spin drift and coriolis on.

http://www.longrangehunting.com/forums/f17/spin-drift-coriolis-effect-69961/


There's a pretty good discussion on it. Some of those guys explain it fairly well.

It's a small factor. Not nearly as significant as other things like wind, as you mention. But if something as simple as reversing the twist on the barrel nearly eliminates one factor to calculate into your firing solution, wouldn't it be worth it?

Not for me. I leave Coriolis and spin drift turned off. Temp, DA, elevation, call the wind as best I can and let-er-fly. See it get there, correct, if it needs correcting.

I understand that, but if you'll turn it on you can see that a left twist does improve spin drift in the northern hemisphere. The ap will allow you to turn it back off whenever you like. It won't be stuck there.

To the Ops question, it is because most lathes are setup for a right hand twist in the US. If you buy Euro such as Sako the twist will the left hand. The best reason for a left hand twist is your suppressor stays tight.

I understand that, as well. My point is spin drift and Coriolis is so negligible that I don't worry about it. In April I should be shooting a mile plus. I'll turn them both on and see if it makes any difference in hits on target. My bet is no. Factoring in all that air, with cross winds, is what will result in hits. Turn focus down and hopefully see mirage a third of the way there, then two thirds, then at the target. Crazy air movements are seen when you get to studying everything between muzzle and target.

edit: I hope Jay (N.T.R.P.) shows up. I'd like to get his take on all this.

I'd be interested in what you find. I haven't had a chance to shoot that far and see any correlation myself.

I do not believe that drift or Coriolis force is an issue. As JG pointed out, having right-hand barrel threads and right-hand twist prevents torque forces upon firing from trying to loosen the barrel.

That gets my vote for being what the right-hand twist is all about.

I'll let you know. I will be using a Kestrel with Applied Ballistics. And I'll cross reference "Shooter" in my phone. My 7 Rem Mag isn't super sonic at 1760, but it is at 1600, so I'll shoot it that far. We'll also have a 338 LM shooting 300 gr Berger's, we'll see how far out we can control it.

I'll take good notes for sure.

Thanks. Looking forward to your findings.

You and Charles mention the barrel threads. If the barrel is mounted properly, is there really enough torque applied to loosen the barrel over time? I understand the forces in action here. It's just hard to imagine how much torque is actually being applied.

Did you even watch the video you posted? It clearly proves that YOU are wrong.

Evidently, since it has supposedly happened, at a match, with high volume of fire. For every action there is an equal and opposite reaction. Bullet spinning left twist down a barrel, barrel spins the other way, unscrewing itself from the action. At least that's the way I understand it.

The guy that does my barrel work tells me he only puts about 50 ft/lbs torquing a barrel on, if memory serves.

I had no idea how much torque was applied to the barrel. I also have no idea how much torque the firing applies, but I could see it being enough, in that case.

While Coriolis and SD do have an affect on a small arms projectile, it's usually such a small deviation that it gets lost in the wind and/or shooter error. You really have to be shooting ELR 2500 yards plus to worry about it. I used to shoot at 1780 yards regularly and density altitude was my only real concern.

If you're shooting a naval gun at a target 25 miles away, you need to account for Coriolis and SD. A 6.5 Creedmoor at 1000 yards; you need to focus on your wind call. I've never missed a target in a match and thought, "Awe [censored], spin drift got me!" It's always been an incorrect wind call or shooter error (yes, I make mistakes too lol).

That being said, having your Coriolis and SD turned on is fine as long as you always enter the correct direction to target. Something you may forget or not have time to do. Shooting a target to the West while having your shot plot to the North will not give you data as accurate as you hope by considering these two variables.

There are no absolutes or only way to do things. It's up to the shooter to experiment and determine their own philosophy. But that has to be determined on the 1000 yard line and not the Internet. So take what I said as a YMMV kinda thing. Thanks y'all.

Good stuff, Jay.

Looks like I found myself on the same page you live on. I said same as you, I'm worried about D.A. and judging the wind(s).

Yep, it's all good man. You can worry and variable yourself to death. At the end of the day it's all about the wind call.



...and keeping ChadTRG42 from trying to steal my holds before it's his turn to shoot. He's really bad about that.

Good stuff. This is why I consult with y'all.

Gospel truth!

I actually shared with him at The Heat Stroke last year, and I didn't lie. Don't know how it panned out for him.

A toilet isn't going to flush in the opposite direction from the direction that water is injected under the rim, no matter what the forces applied to it. In the video, they moved over to a lavatory to show the opposite spin direction.

Well then here's another video for you:

I can't wait until this toilet mystery is solved.

Negligible? Don't think so. Newtonian physics that have been mathematically proven since 1687 is not negligible.
As one who has DOPED my .308 125 yards beyond transonic 1225-1290, spin/coriolis is not negligible.
4 years of meticulously data with same rifle and same hand load in a host of external ballistic conditions is not negligible.

So you did this in zero wind conditions, that you know your drift was due to bullet spin and Coriolis?

What load are you running?

"did this..." Which time? 4 years of data in different exterior ballistics conditions and altitudes is not a one time "did this" test.
Calling wind is an important factor and one most often miss calculated. But negating other exterior ballistic conditions - temperatures, density/volume, altitude, including spin, drift, and the Galilean model of a heliocentric universe tells me that planet earth is spinning on an axis and that coriolis effect is real.

24" Krieger Bull Barrel 1:10 Twist
168gr Berger VLD
Varget Powder
Nosler Brass
Fed. Primer
.012 off lands/freebore

With all those notes you should be able to tell us how much drift was caused by Coriolis or spin drift, absolutely ruling out wind.

G7 .242
MV must be about 2700 fps which put you trans-sonic at about 1030 yards
Probably 43.0-44.0 gr of Varget?

Never has anyone said that DA, and temp should be ignored. In fact it begins to matter around 400 yards with your load.

you my friend are crack... sorry to bust your "mathematically proven" bubble..... just the same as if you mathematically keep dividing 1 by half you'll never reach zero.....

and there is always wind at 1200 yrds.......

I have been an amateur radio operator for many years, and have worked on radio towers as far as 200 feet high. What is really amazing though - is how much difference just fifteen or twenty feet of altitude can make as far as wind speed and direction are concerned. Temperature, too. On dozens of occasions I have noted still air and sweltering heat at ground level, climbed a modest height - and was suddenly very comfortable in a cooling breeze while the ground crew below were still sweating through their clothes.

Can you "read" this wind direction and speed change from the ground? - Nope. Not along any significant stretch of the bullets flight path. Many times there will not be a blade of grass stirring - at ground level.

How far do you have to hold over when shooting at longer ranges? - The longer the range, the greater the hold-over, of course, and if the land is not billiard-table flat, then the bullet may wind up considerably further above ground level than just the necessary hold-over for the target - which in many cases is located on a slope that puts it high enough for easy spotting at distance. Errors accumulate from factors impossible to detect or judge from ground level.

- But we are going into sub-micro nit-pick mode here over Coriolis force etc..

That is not the most ridiculous thing going on here,though. - The ignorant/arrogant assumption of expertise and control is the real thigh-slapper.

Everybody got your hip-waders close at hand? - The meter is pegging out!

Look up maximum ordinant.

Most cartridges have a hold over of 8 to 10 Mils (24' to 30'), above center of the target, at the target, at 1000 yards. But the bullet doesn't come even close to getting that high above a straight line from muzzle to target.

Yes the wind above the ground is more significant since there is less air resistance 5', 10', 15' off the ground, due to no obstacles screening the wind. But our bullets rarely get to those heights inside 1000 yards.

Tomorrow I can consult my Kestrel with Applied Ballistics to give some maximum ordinances to go with some distances.

There are more factors at work there than just air resistance. It would be nice if the world was that simple and straightforward - but guess what?

Wind direction and velocity rarely if ever cooperates with those who like to pretend that they have chaotic systems all worked out. It varies due to a variable number of factors that are not possible to detect or measure from ground level. Air moves around for a variety of reasons, and so the longer the distance involved, the greater the level of uncertainty as some influences are quite local in nature. - Cooler air flowing down a slope for example, or warmer air rising from rocks that are warmer than the surrounding grass. Moisture variations in the soil. Sunlit or cloud-shaded areas. - The list of influences that may accumulate or cancel each other out is too long to note here.

This, in part, is why the weatherman can only very rarely give us an accurate call on what to expect the next day, much less a week from now. - And he is looking at the coarse, large-scale air movements are that are by far the easiest to detect and predict.

Ignorance and arrogance have a natural affinity to each other. One depends so much upon the other.

Long range shooting is as much art as it is science. The level of uncertainty precludes it from ever being reliable about following a pet formula or statistic. This is what the challenge of long-range shooting derives from, and it is also why a good shooting score at long range is exhilarating, not boring and predictable.

It is also why only a jerk would shoot at a game animal at much over 400-500 yards or so - no matter how "good" they have may have convinced themselves that they are.

Long shots at Islamofascists, prairie pups or coyotes (Varmints, in other words) is one thing - but a sportsman will not roll the dice on maiming, injuring or losing a game animal.

Period.

If you make the rounds of the various shooting forums, you'll see something new pop up... New shooters looking for advice on the best equipment for shooting at game animals at 1700 yards, 1000 yards, 800 yards etc... All kinds of distances that no experienced, mentally fit sportsman of any skill level would ever consider when hunting game.

The current long-range shooting fad is a big part of that. - It is a BS factory on stilts, and so long range shooters have a particular responsibility to set a good example in this area. The ones who refuse to do so trail slime behind, wherever they may go.

What?

Yes, I know this is a sore point for you... Eventually, you will have to wake up and small the coffee, like it or not.

Please explain...

Ignorance (ignore-ance) is a condition where plain facts are somehow incomprehensible - to somebody who simply does not wish to know.

Others may see the same information and understand it readily. Objectivity will do that for you.

This is why arrogance is commonly associated with ignorance, but far removed from objectivity.

An objective outlook has no skin the game, in other words, and so is ready to absorb facts that the ignorant and the arrogant must at all costs ignore.

None of this is rocket science. To high-school kids who make the debating team, it is all a pretty basic part of the rules of the road. - Just a simple reflection of reality.

If what I have said about uncertainty increasing with range still escapes you and you really want to know, you'll re-read as necessary until the light bulb over your head switches on. The more skin that you have in the game though, the greater the level of ignorance that you will have to overcome.

It's not easy. - I know from personal experience. Once you develop the knack for objectivity though, you'll be very glad that you did.

What makes no sense to me is where all this worthless drivel comes from you, after a friendly post I made mentioning maximum ordinant.

I imagine there are mental therapists in El Paso that can help you.

Yesterday I dodged traffic at two different car wrecks, assisted at a car fire on a six lane road, answered a suicide call where a man had cut his own throat from midline trachea through the carotid spraying blood all over the bathroom, with his 14 year old son and wife in the next room (where I got to tell her her husband wasn't going to live) then went to a working structure fire at 0300. I slept four hours out of 24, then worked all day today.

I AM QUITE SURE I HAVE MASTERED OBJECTIVETY!

So take your foolish advice and stick it where the sun don't shine.

I have nothing relevant to add to the original discussion, but prayers for the woman and her son. I can't imagine the hurt they're going through. Sad deal.