Lapua scenar bullets barrel twist recommendation?

J

Jeromeo

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Is there anywhere that states what barrel twists are good for the Lapua scenar bullets? I've got a .260 rem shilen barrel with a 1:9 twist on order and am curious about the 139gr. scenar. They have quite a high BC. :ar15:
 
It should work with them just fine. Most 260 shooters use 1:8 twists, but 9" should be no problem. Not all guns like all bullets, so wait and see what seems to work the best before investing in a boat load of bullets.
 
I have two 6.5 mm rifles now and several friends who shoot them too. We have definitely seen better accuracy with 1 in 8 twist than with 1 in 9 with heavy bullets. I use the 139 Lapua in my 1 in 8 and am very happy with it's performance. The Sierra 142 grain bullet is a good example of a bullet that performs better in 1 in 8 than in 1 in 9. Best bet talk to Shilen or your smith and follow their advice. Good luck.
 
The Sierra 142 grain bullet is a good example of a bullet that performs better in 1 in 8 than in 1 in 9.
Click to expand...

Yet for some reason,the Sierra 142 gr bullet is the bullet that Cooper chooses to test fire their 1 in 9" twist 260 rifles,and they do quite well with that bullet.
 
I have read many things and not all you read should you believe. I can't remember if it was M.L McPhearsen, Glen Newick, Bob Pease or good old Boots. One of them said to get the best accuracy you should shoot the heavest bullet that your barrel will stabalize. This so the bullet is not over stabalized and therefore "goes to sleep" quicker. That in turn, theoretically is more accurate. But as Obtunded said "not every barrel likes the same food. :D There are many shooters on this forum and that knowledge is priceless. If I am in any way incorrect let me know. Sometime all the books and opinions mix together.
 
If you have the bullet dimensions the Border Barrel calculator based on McGyro code can give you an idea where you stand. Be sure to enter your 9 twist and it will then give you a graph of stability vs velocity. While 1.4 may be the ideal conservative number for stability, I believe many go lower. Temperature is an issue and you should also enter your lowest expected temperature. I've had 140 grain Nosler Partitions and 140 grain Sierra boat tails go unstable at freezing temperatures with a 1 in 10 twist. They calculate out to a stability factor of about 1.0 when they do go unstable.

http://www.border-barrels.com/barrel_twist.htm
 
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