Below is my first sight-in for the Nosler 223 77g heads at Nashua’s 600 yards range at an F class target in single shot mode with my AR-15 w/16 inch barrel.
I told the range officer that my JBM calculation said that from my zero at 100 yards, it needed 26 minutes up but he wanted me to start at 15 minutes up and thought my calculation was in error (that was being kind). It took all of 26 minutes virtical adjust to get it zeroed after 5 shots and 11 more minutes up. My software was correct but you must follow the range officer’s guidance as we do not want to overshoot the target. The scope was terrific at 18x as was the 2 stage Timney Trigger. The Nosler Custom bullets and Custom Brass is superb. I just need more speed.
After the first 5 shots in the 8/9 ring the bullets began to drop so I kept bringing it up to 27 minutes to get back near the 9 ring. Bullet speed at muzzle was 2320 fps but at 600 yards there was no crack from the sound barrier, thus at the target I was subsonic. Perhaps at around 1000 fps where 1100 fps breaks the sound barrier. There was little wind to affect the lateral movement seriously. The only thing I could figure is that just warming the barrel a bit was enough to drop 8 inches, so I had to keep adjusting to compensate. I will reload for Saturday’s shoot. I expect I will not win or place but burning powder is the only way to see what all the front end works does. I had fun and learned a lot! Others shooting 6mm, 6.5 mm and .308 did so much better group wise as the bullets traveled faster and with heavy bull barrels most bullets hit the 9 or 10 ring.
If the wind blew just 5 mph laterally I could be right or left by 25 or so inches. Yep that much! A faster bullet helps immensely. I will try the 69 grain Nosler’s at a future practice to see the difference. I will keep you posted on Saturdays shoot.