Barrel Twist?

[dion]

What twist rate would you guys suggest for the win 284. Will be shooting 162 to 168 gr. bullet? Need Advice

 

[therifler]

What distance are you going to be shooting .

 

[dion]

400 to 800 yards

 

[ThunderDownUnder]

Why not calculate what twist rate you require for the bullet you have selected?
You need to know the length, diameter and velocity of the bullet and a few atmospheric conditions and by using Millers Formula you can calculate the stability factor (Sg).

Bryan Litz recommends a stability factor of Sg >= 1.4 and by following the link to a spreadsheet I put together recently you can do your own calculation. Just alter the twist rate input box to see which twist rate provides the stability you need for the bullet you want to use. It can also be used to calculate spin drift (gyroscopic drift).

If you dont want to use the spreadsheet a 1:9 twist should cover the bullets you want to shoot right out to the 180gr VLDs.

Bullet Gyroscopic Drift & Stability Calculator: http://www.safclass.com/Spreadsheets/Gyro%20Stability%20and%20Drift%20Calculator.xls

Ian

 

[oldroper]

What twist rate would you guys suggest for the win 284. Will be shooting 162 to 168 gr. bullet? Need Advice

Best thing to do is talk to the barrel guys and see what twist they recommend and you sure don't want to get locked into one bullet weight IMHO. I like to give the gunsmith acouple dummy rds with different bullet weight.

I have a 284 in the works using a Bartlein 5r 1/10 twist barrel finish 24.5" long. I plan on using 150/160gr bullets OAL length be appr 3.000" . I also have a 280AI being rebarrel with a Lilja 1/9 twist barrel for the 160gr plus bullets that barrel be 26" long.

You'll like the 284 good caliber.