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duncaninfrance
03-28-2009, 02:57 PM
Is there such a thing as a chart or series of charts that will give the correct rifling twist for various calibers and bullet weights?

versifier
03-28-2009, 03:55 PM
There is a formula, based on the Length (bearing surface) of the bullet.

Proper Twist:
150* x caliber diameter in inches x (cal diameter/bullet length)
*For velocities over 3000fps use 170, and under 2500 use 130

Proper Bullet Length:
150 x cal diameter x (cal diameter/twist in inches)

Bear in mind that this is a general guideline. It's usually pretty good, but I can't tell you how many times I have seen a barrel stabilize a bullet that is much too long or too short by the book. Neither rifles nor bullets can read. ;)

The bottom line is you have to actually shoot it to get that particular barrel's opinion. Most recently, I advised a shooter that his .223 with a 1/10 twist would probably not stabilize a 70gr bullet. Usually they keyhole and pattern like a shotgun. He proceeded to shoot a one hole group with the rifle at 100yds with his handloads. His comment was "I'd read that, too. Don't tell my rifle, OK?"

runfiverun
03-29-2009, 02:32 AM
generally the longer [heavier] your bullet, the faster your twist rate.
the greenhill formula above is pretty close though.
remember it is just a guidline,and you can go over or under what it says.
mainly cause, guns are just like that. some will some won't.

duncaninfrance
03-29-2009, 08:45 AM
Thanks guys.
I was given this ling by someone on another forum which is very good.

http://www.riflebarrels.com/products...wist_rates.htm

swamp
03-29-2009, 11:36 AM
Your link doesn't work.:cry:

Ed Barrett
04-28-2009, 04:24 AM
If you look at the tables at the end of each section of "Cartridges of the World" they list the twist rates for each cartridge.

missionary5155
04-28-2009, 10:33 AM
Good morning
The NRA Fact Book has a section on ballistics,stability, rotation... does get real DEEP... simple easy and I enjoy the book.
Mike in Peru

winshooter
05-18-2009, 03:30 AM
Is there such a thing as a chart or series of charts that will give the correct rifling twist for various calibers and bullet weights?


Here's a few threads you can follow:

http://www.riflebarrels.com/products/caliber_twist_rates.htm

http://www.nfa.ca/content/view/129/197/

http://www.montanabulletworks.com/wst_page11.html

Mike