Let's talk LH Gain Twist barrels

Tex68w

Mister Bevilaqua
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Minuteman
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  • Mar 10, 2017
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    So after reading about these and watching a few videos, including Lowlights on the Bartlein offerings, I am intrigued. How many of you run these and what are your findings? I can see the benefits, but what are the drawbacks, if any? Am I wrong to assume that you'd benefit more from using one on a long action or magnum caliber over a short action?
     
    The gain in the twist used is pretty small and is more about ensuring positive rotational acceleration than anything else, as a slowing of the twist rate is much more likely to cause stability and accuracy issues.

    Keeping it exactly the same, or a small gain twist doesn't hurt. Larger gain twist require projectiles with driving bands and would cause more jacket deformation on traditional bullets. That said, the method is used on artillery because it's not as easy to get a large mass like a 155mm round rotating instantly.

    Left hand twist works to mitigate Coriolis in the northern hemisphere, that's physics. Otherwise I think they perform the same as anything else. I've shot left and right hand rifling and to be honest 99% of the time wind screws you bad enough or you don't shoot far enough away you don't see any difference unless you really look for it.
     
    About 10 years ago we had a Junior Highpower (across the course) shooter with a left hand rifled 7 twist. He swore, as did a couple other guys, it recoiled more into you body as opposed to against. The were convinced they could folllw through and follow up quicker. This kid could shoot. Rifle shot. Was it the barrel or the confidence it gave him to drive it? Wish I could remember his name.

    So much of his game is mental. If you roll up to the firing point ready, practiced, and confident in your kit you are ahead of the game. If a specialty barrel gets you there then it's worth it.
     
    Two components of coriolis. One always right in the northern hemisphere, or always left in the south, or nonexistant on the equator. The other is an elevation component shooting east/west because of the earth spinning and that spin either "chasing" or "confronting" the bullet's path.

     
    Thanks for that Ledzep. Although i rarely shoot far enough to worry about it, I've always had a hard time grasping that the projectile will drift right whether shooting N to S, or S to N in the Northern Hem.

    Now i kinda want to find a merry go round...
     
    Coriolis is real and it is physics. You can hold for it if you wish. A word of caution though, unless you are shooting at ranges over 5-20 miles, I doubt you will notice the effects. It becomes important in field and naval artillary where ranges are measured in multiple 1000s of yards and trajectories send projectiles very high above ground level. Apogee measured in 1000s of feet and TOF in the minute range.
     
    No doubt. Spin drift is also real, and is also more of a thing for artillery and super-long trajectories. Neither is worth worrying about probably within 1500yd on the typical size targets we're shooting at (2 MOA or so) because wind--- hell just the error in your ability to read wind is going to be several times more important than the effect of spin drift or coriolis. Nevertheless, a left hand twist does work against a northern hemisphere coriolis and a right hand twist works to add to it. That's all I'm saying. Not saying they exactly cancel each other out, just that they work in opposite directions.