The Ruger American AR Pattern rifles Truly a modern classic of a rifle, designed with the simple and efficient ingenuity to utilize commonly available AR-15 / STANAG pattern magazines for common intermediate calibers, thus increasing it's overall effectiveness and keeping costs low. When you don't need capacity though and prioritize ergonomics and comfort, the Duramag SS Flush-Fit magazines are a perfect solution for both your Gen 1 and Gen 2 Ruger American rifles with the OEM stock / mag-well for AR pattern magazines.