I made it to the range today, sunny and 75 with 8mph SW wind. Here are the results over the chrony set out 15ft. Shot 10 rounds of Sierra 55gr BlitzKings in my Tikka .243 with 46.2gr of H414 = LO-3456 HI-3486 AV-3472. During development I shot a 3/16" 3-shot group with a 3-shot/5 target average of 11/16" and that was a the day there was a 20-25mph wind. I also shot 10 rounds today at the gongs at 300yds. I held my Burris Ballistic plex rectical right on 300 mark and just hammered them.
Shot some other loads over the chrony as well. Hornady 65gr V-Max with 46.4gr of H414, same rifle. I only had 4 rounds so not a real good test sample, but this was a bit odd. Lo-3456, HI-3486, AV-3472. Im not kidding, no BS, same as the 55 Seirras. This is a very good load in my rifle. I have shot a 3-shot 1/4" group with this load before.
Shot 10 rounds of 80gr Berger FB Varmint with 41.2gr H414 = LO-3011, HI-3051, AV-3029. This load I have also shot a 1/4" group with.
Shot 5 rounds of 100gr Sierra Pro Hunters FB with 39.6gr of H414 = LO-2838, HI-2875, AV-2860. This is one of my favorite loads, as I mentioned above, not pelt friendly. I have shot my best average with this load at 5/8".
Now this was a little interesting. Using my sons Tikka .243 with the same 100gr Pro Hunter load. Shot 5 rounds = Lo-2923, HI-2953, AV-2938. That's a 78fps faster average than my rifle. Of course he says "Yah! mines faster". Probably because his rifle only has like 400 rounds down it and mine has like 4000. What I didn't tell him, is that my rifle is more accurate. I think the powder in his loads and mine were from different lot# jugs.
I also shot 4 different 55 grainers/.224 in my new 18" SPR AR-15 over the chrony today. Great day at the range with my boy.