19 February 2003, 08:57
jrswick@yahoo.comTwis Rates for 6.5 Bullets
All,
6.5 twist rates? What would be the twist for 140 grain, 6.5mm bullets? I have seen sites saying 1-8 and others 1-9. Your thoughts and expierences?
Cheers,
Jason
19 February 2003, 09:08
HunterJimJason,
US rifle manufacturers like Remington use a 9" twist, and that is enough to stabilize all 6.5mm/140 grain bullets (and under). My 6.5-'06 has a 9" twist and will shoot round-nosed bullets up to 160 grains (but doesn't shoot the 165 grain semi-spitzers).
European builders often use a 200 mm twist (7.87"), and that will stabilize the 160s such as the original 6.5X55 loading.
jim dodd
19 February 2003, 10:40
<JOHAN>jrswick@yahoo.com
you can calculate the twist with the greenhill formula. I hav used 8,5 in al my 6,5 barrels because it will stabelize heavy bullets even when they don't get much velocity.
I have friends who's rifles will not stablelize 140 grainers, the twist is 1-9. If you have plans on shooting 140's and not any lighter ones I would go for 8,5 or 1-8.
/ JOHAN