The Forest Wolf, a fearsome sentinel weapon, had a shooting range of 400 meters, and within that range, the scope could see things very clearly. Coupled with the tower bonus, zombies within a 500-plus meter range became targets. Another factor was the Forest Wolf's power; as long as the shot didn't hit a limb, normal zombies would go down with a single bullet. A headshot from White Crazy Savage would take them out instantly, while Blood Ferocious Ma would take one more shot. Titan would kneel with two shots, and after the fourth kneel, they'd die with the next hit.
Though both were bolt-action rifles, the Silencer and Forest Wolf were entirely different weapons. The shooting effect brought a tremendous sense of power, so it was no wonder Emerald Feather got addicted to using them.