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.