My longest shot measured with my range finder was 326 yards. I knew it was long, so I walked to the dead dog and shot back to my car to be sure of the distance. I killed him with the 5th shot from my Remington VSF .223 and my very accurate hand loads. The final and lethal shot, I held a few inches high and a few left. I subsequently bought a Rem 700 VLS .243 and spent considerable time building accurate loads and practicing at the 300 yard range. With perseverance and practice I managed to kill several dogs at 300 yds, but I abandoned the idea and sold the gun because I missed a good deal more than I connected. I still shoot lots of dogs, but most under 200 yds with my 17HMR.
I now shoot with my buddy who is a long distance competition rifle shooter of considerable skill; much better than I am. His equipment is hand built and wicked accurate. We haven't tried for ultra long p-dog shots yet but he has video of shooting a couple at 275 yds with his 6mm. Setting up the video depends entirely on a patient and dumb p-dog. Next spring he'll try for longer shots. Last story. He also built a 6.5CM for deer and 2 weeks ago he shot a doe through the heart at 350 yds.
I now shoot with my buddy who is a long distance competition rifle shooter of considerable skill; much better than I am. His equipment is hand built and wicked accurate. We haven't tried for ultra long p-dog shots yet but he has video of shooting a couple at 275 yds with his 6mm. Setting up the video depends entirely on a patient and dumb p-dog. Next spring he'll try for longer shots. Last story. He also built a 6.5CM for deer and 2 weeks ago he shot a doe through the heart at 350 yds.