If there's gonna be a rifle that use caliber higher than .308 or x54 for a long range sniping most likely it'll be capable one shot a player (or at least uncon), so to keep it balanced with other weapons (besides extreme rarity) you could use something like this. Bolt action single shot rifle (without internal or external mag). Very powerfull yet gives you only one chance to hit the target, if you missed most likely target will dissapear. https://sketchfab.com/3d-models/bfg-50-rifle-4a4f309a2590461583bdc71c9e7a50ec