With mods, the rifle has 0 dispersion, and the bullet has 30. In general, you can usually get most rifles to 0 dispersion with the gun mods you can craft. That said, other guns have lower dispersion on their bullets, like .308 (15 dispersion).
Even then, hitting a target from so far away can be hard.
Best thing to do is find a stationary enemy, like a turret, then burn through ammo.
Furthermore, it’s a bit OP, but if you’ve got BlazeMod (I think that’s the mod that has it), craft either a scorpion ballista or a slingshot cannon - the ammo and those vehicle-mounted guns has zero dispersion, though for the slingshot cannon only its explosive canister ammo has zero dispersion. It can fire from 60 tiles away, so it’s a bit easier to score a shot with them, though making ammo can be time consuming.