From Halopedia, the Halo wiki
Silvertip is an achievement in Halo: Spartan Assault. It was released on August 29, 2013 as part of the title update, Operation Hydra, along with four other achievements. It is awarded when the player destroys all the Emp'seam-pattern Antlions with the Grizzly tank in Operation F, Mission 2. The achievement is worth 10 Gamerscore on Windows systems and Xbox 360, and 20 Gamerscore on Xbox One. It is represented by a circle with a Grizzly inside it.