New for 2021 - The Schmeisser S60 .223/5.56 60 Round AR-15 Magazine WITH WINDOW! American Tactical has partnered with German arms manufacturer Schmeisser GmbH to exclusively import and distribute the Schmeisser S60 60 round AR-15 magazine. Made from glass reinforced polymer, this patent pending magazine features a unique follower system that allows for double capacity from a normal AR magazine without being bulky or cumbersome. Designed to shoot both .223 REM & 5.56X45MM, the Schmeisser S60 will give you an instant capacity upgrade over the standard AR mag at an affordable price for your AR Carbine or Pistol. Now featuring a clear polymer window and a last round bolt hold open integrated in the follower (Upgrade from Gen 1) The Schmeisser S60 was built specifically for .223REM or 5.56X45MM ammo only. Schmeisser & American Tactical have done some testing and found that the S60 may not operate with all types of .300 Blackout ammo. Due to inconsistencies with different brands, Schmeisser does not recommend using 300 Blackout with this magazine. Failure for the magazine to operate with 300 Blackout is not covered by American Tactical's Limited Lifetime Warranty. Product Specifications Manufacturer: American Tactical Model: AR-15 Platform Caliber: 223/5.56mm NATO Capacity: 60 Rounds