Barrel twist

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SBR4590
Posts: 25
Joined: Fri Oct 29, 2021 4:30 pm

Re: Barrel twist

Post by SBR4590 »

Thanks for all of the replies and suggestions. I'm now more confused as to which way to go than before, LOL. Starting in 1992, I've shot my Shiloh's in competition at Quantico, and the Forbes range in Colonie, NY. Once I started shooting a Borchardt I had specially made with an 1-18, I was hooked on the user friendly Borchardt action. Still send a few rounds down the Shiloh's though. Reason for the current project is, I don't want to scope my other Borchardt since I had it built to Creedmoor specs.
Will update when decision made.
Thanks. Frank. NYC
SchuetzenDave
Posts: 864
Joined: Mon Jan 07, 2013 9:07 am
Location: St. Albert, Alberta

Re: Barrel twist

Post by SchuetzenDave »

Caliber 0.459 Inches
Bullet Weight 535 Grains
Bullet Length 1.43 Inches
Barrel Twist 18 Inches/turn
muzzle velocity 1250 fps
Temperature 50 degrees Fahrenheit (59 is standard)
Pressure 29.92 inches of mercury (29.92 is standard)

Sg = 2.43

Sg (gyroscopic stability factor) shouldn't be less than 1.4 (not enough spin - will tumble down range).
If Sg is greater than about 2.0, you may gain some accuracy by going to a slower twist barrel.
However we like to go over 2.0; which is overspinning the bullet, which compensates for drag over long distances (1,000 yd.)

The Postell nose is a good design for dynamic stability for long distance shooting as is the Creedmoor, Government and Elliptical.
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