Neither7.62x54 or .308 are is guaranteed one tap. Especially at any range. Especially if target has protective gear over distance they deal little damage. Hell both plates and helmets have a chance to deflect the bullet. 308 lose power past 600 meters and 7.62x52 over 800. I snipe on a daily basis over long distances both in the offline to warm up with zombies and online. In 1.04 you can one tap a zombie at 800 meters with mosin and svd (rare instances you might have to hit them twice) in 1.05 it can take upto 4 chest shots on a zombie and quite often requires 3 chest shots which is crazy. Add protective gear and unpredictable player movement to this equation and sniping will be less rewarding.
Even if they were to nerf it, this is just crazy. Random zombies taking three shots to be killed with SVD in effective range of the weapon...