Glad to read a few more are recognizing the LR potential of the .224 heavies with fast twists. I've been doing this for over a couple of decades with 223/5.56's, 223AI's, 22-250's and 22-250AI's. Several 223/5.56 bolt guns with long throats and 9 and 8 twists and AR's with 8 twist. I've used the 75 AMAX, 80 AMAX, 75/80 Bergers on top of loads of an old lot of Data74 powder, CFE223 and AA2520(Very similar to the Data74 powder). In the 26in tubes, I've been running the 75's at 3,000-3,050fps, the 80's at 2950 or so and the AR's with 24" tubes in the 2,900+fps
600yd 6" gongs and 1,000yd 10" gongs are great practice for the matches and practice for wind readings. IN the 22-250 and 22-250AI, I have pushed the 80's out to 1 mile! Loads of fun.
Before our range changed, we had a 930yd P-dog gong that really took a beating from these rifles and loads.