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Posted: 12/19/2007 9:35:50 PM EDT
Looks like ammo-oracle is down again - here is a backup link: ammo.ar15.com/ |
60 or less.
68-69 works in all 1:9's..... it is the 75/77's that only work in some - and longer barrels tend to have more success.
So will 1:8. 
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The twist matters for every caliber. Generally the longer, heavier bullets need a faster twist but 1/7" is about the fastest and 1/14" is the slowest. Pistols run around 1/16" to 1/18" on the average but there are 1/32" for the hot 9mm/38 autos and a new 1/24" left hand gain twist for pistols called an "AET" barrel. 1/10" is likely close for your .243 with 85-100 grain bullets. A27257 |
That's not the backup link, that is THE link... [ETA] THe information the OP seeks is in the AMMO FAQ, including the Greenhill formula and links to a more extensive discussion on the subject. |
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