When I first started playing this game, I treated the Varmint Rifle as just a throw away weapon that I'd get I'd get rid of as soon as I got my hands on a Service Rifle. But then I discovered that it made a good compliment to the Service Rifle for distance shots because of the scope and the fact that it had a lower spread. That extended the life of it until I got my hands on a Hunting Rifle with a scope attachment. But just recently I discovered that it is also the only weapon in the game that has both a scope and a silencer, making it very useful for sniping indoors where sound can be an issue. Not only that, but the scope is a night scope, so you can see anything within an interior space regardless of how dark it is. Plus it can use both Armour Piercing and Hollow Point bullets, so no matter what the target there's something that can be effective against it. To me, this makes the Varmint Rifle/Ratslayer useful for the entire game, not just at the beginning.

sniper rifle has a suppressor attachment for it also, as well as the anti material rifle having one.

normally i abandon the ratslayer after the hunting rifle.

Every play thru these days I make a beeline for the Rat Slayer which is a very nice Varmint Rifle. Using all three types of ammo it kicks ass and never gets old.