Thread: rifling twist what are the effects?

im not sure if i have this in the right forum, but for example tikka 223 seem to have 1 full twist per 8 inch and 1 full twist per 12 inch options ( if i understand this correctly? ) so the 1/8 will make the bullet spin more correct? what are the pros and cons? does the fact the projectile has to rotate more use more energy thus slowing the projectile down? but also improve accuracy? and so in 223 cal for 100m shot what would be an ideal twist rate to go for?