Admittedly I'm gun ignorant.
Is a 1 in 10 twist suppose to be better than a 1 in 8? Does the caliber determine how many 'twists' a certain barrel should use? Please forgive my ignorance, I'm just wanting to learn. Thanks

The needed twist rate will depend on caliber, bullet length, and to a lesser degree velocity. When in doubt go to the faster twist. If the bullet is spun up faster than it needs to be it will still be stable it just may not nose over at longer distance, and will continue to fly nose high.

Thanks Rhys,
I'd ask what the recommended twist for say a .270, .300, .338, and .375 would be but then I can already see that you'd need to know what bullets I'd plan to use. Too many dang variables.

quote:

Originally posted by bluefin:
Thanks Rhys,
I'd ask what the recommended twist for say a .270, .300, .338, and .375 would be but then I can already see that you'd need to know what bullets I'd plan to use. Too many dang variables.

Reading the list of calibers, it looks like you are interested in hunting rifles. The twist rates used by the manufacturers are a bit of a compromise to accomodate the heaviest commonly used hunting bullet, which may be more twist than the lightest one needs, but you aren't likely to be able to notice the difference. The manufacturers have worked that out years ago.

I'd suggest you go to the Savage or Remington WEB sites, for example, and see what twist they recommend in their rifles of those calibers. That will be pretty close to optimum for that caliber in a hunting rifle.

Fitch

Bluefin, have a look at All about bullets which should help to further your education on this topic. Most calibers have a std twist or two these days which cater for the most common bullet weights that they shoot. If you think you will only ever shoot light for caliber bullets you can get away with a slightly slower twist, but you may need a faster twist to shoot heavy for caliber bullets. By way of examples, .243/6mm barrels with a 1:12 twist will shoot 85/90 gr bullets just fine but not so good with long 100gr & heavier as Remington found out when they brought out their 244 Rem years ago. Back with a 1:10 twist & named 6mm Remington it was fine. On the other hand, 35 Whelans often have a 1:16 twist which is OK for factory weight bullets but marginal for 280-300gr bullets that some like to try these days. 1:12 does better for these. Try a few examples in Steves pages & you'll soon see what I mean.
Steve ('nuther one )

As others have said, each caliber has a "standard" twist and even variation among caliber -mainly in custom barrels - where a specific bullet is intended. Rule of thumb is the longer the bullet the faster the twist. Muzzle loaders intended for ROUND BALL loads only, typically have a very slow twist, as much as 1-60 or even more sometimes. The round ball only touches the bore at is "equator" thus providing a very minimal contact. A 175gr. 7mm bullet on the other hand has a very long contact portion and hence a rather fast twist!