For those of you who just picked up (or will) the new issue of Handguns magazine, there is an interesting article about bullet stability after penetrating barriers, using different barrel twist rates. (Twist and Shout: by Dick Metcalf) I won't spoil the article for those who have not read it, but if you have already, you will probably be wondering what the twist rates are for GLOCK barrels. Here ya go.. For all 9mm, 10mm, .357, and .40 caliber pistol lines, the twist rate is - One in 9.84 in. For the .45ACP and .45GAP lines, the twist is - One in 15.74 in. Wanna kill these ads? We can help!