Green Mountain .920 Bull barrels for the Ruger 10-22 utilize a tight Bentz chamber design with perfect target grade rifling. Sizes range from 16" x .920" to 28" x .920". One 18" .920 bull fluted barrel even comes with Fire Sights..In addition to a variety of 22LR lengths, you could choose a 20" subsonic sniper barrel with a fast 1:9 twist, or a stinger chambered barrel for varmint shots.