Home Forums Hunting & Shooting Ask The Gunwriters 223 Rem, New school or old school twist rate?

Thanks for the visual, Al. As mathman mentioned, it’s a multivariable problem. What really matters is bullet body length, as you’ve described here, but bullet body length is a function not only of bullet weight and overall length, but also bullet shape. Some heavy VLD designs with long boat-tails and long ogives have very short body length, and consequently require short throats if the bottom of the bullet body is seated to the case neck/shoulder junction, assuming magazine length is not a constraint. My illustration above shows how some lighter, shorter bullets may require a longer throat than heavier, longer ones, but I think that’s really only the case with bullet weights that are somewhat similar. As both our images show, very light bullets generally have a shorter body length than much heavier ones, even with very different bullet designs. Bullet weight seems to be the dominant variable, and only if weight is similar do length and shape typically play a significant role in determining bullet body length.