I finally made it to the range today. A few weeks ago I loaded up some .223 rounds for my Vanguard. I had been shooting 55 grain bullets through it. When I started reading and asking about twist rates I came to the conclusion that I needed a lighter bullet for the 1/12 twist rate barrel.
I loaded eight different loads using a 40 grain Sierra Blitzking bullet and ranging from 24.3 to 25.7 grains of AA2230 in 2/10s of a grain increments. I fired a few 55 grain bullets through, just to warm the barrel. The first set of three rounds (24.3 grains powder) was about 5 inches high at 100 yards so I adjusted the scope down and continued firing. The rest of the shots were a little high and to the right but I didn't care much where they went, I just wanted groups (I just didn't want them all to be 5 inches high).
The first group (24.3 grains) was the best one of the day, it measured .566 center to center. The next best was the last (25.7 grains), it measured .709. As you can see from the first picture, a lot of the problem was ME and not the rounds. I think the group with 24.9 grains also has a lot of potential to be the load I will go with since it was the only group with at least 2 holes touching. I will load up a few more with the 24.3, 24.9, and 25.7 and try again with just those three and next time I hope to remember to take my lead sled
My next ladder test will be with 34 grain Midway Dogtown bullets. I will find a load that the Weatherby likes. That test will probably take me another few weeks.