Just purchased my MagLula UpLula from Bass Pro Shops (formerly Cabela's) and works well in loading both my Ruger Security 380 Lite-Rack double-stack and single-stack magazines. Three things that I learned that are important. (1) read the instructions thoroughly and watch some YouTube Videos. (2) ALWAYS hold the UpLula firmlly in your dominant hand and ALWAYS feed ammunition into the magazine with fingers of your non-dominant hand, and (3) the lock and unlock lever is NOT EASY to move "up and down" to lock the UpLula when storing. Tip: (use the digit(s) of the finger(s) of your non-dominant hand and it will be easier as it "breaks in" with repeated use.)