I have had a Dtech 6x45 with a 20" barrel for a number of years. It has accounted for a variety of critters such as coyotes, bobcats, fox, raccoons, skunks and two deer. I shoot 75 gr. Sierra HPs that are wonderfully accurate in my rifle. Those bullets behave more like a hunting bullet at 6x45 velocities rather than a varmint bullet.
Reasons why I like the cartridge - It's easy to load for, works great in an AR-15 platform, fits standard AR-15 magazines, has a large variety of bullets and weights available, and is a pure pleasure to shoot with great accuracy. It isn't too much nor too little for most animals up to deer.
Here is a groundhog target I shot at 175 yards. The top two rounds were for sighting. After I rezeroed, I fired two rounds that are practically touching. Not bad accuracy from an AR-15 at that distance. The groundhog target is an actual outline of a real groundhog I shot one time and traced its body, so this target is a real-life scale.
As mentioned, it works well for a variety of animals. Nothing great or fantastic about the round, but nothing bad either.
It's just a good solid performer with more horsepower than a .223 in that you can shoot heavier bullets as well as
larger diameter bullets.