[Unclenick]

If you can hit the center closely enough at 100 yards, and if we assume the BC from Lehigh is accurate at low velocities (it may not be), it looks like a muzzle velocity of about 1740 fps (drops to 1727 at 15 feet) would land going 1500 fps at 100 yards, which about 6.5 grains of Trail Boss should get you and it still gives you about 83% case fill at that load level (assumes a 24" barrel). However, having looked at a lot of Bryan Litz's BC measurements, I am not sanguine the claimed 0.278 BC will hold up at 1500 fps. It would be best, therefore, to use an optical chronograph set out at 100 yards to confirm impact velocity before setting up your ballistic medium.

The Miller stability estimator says you are probably going to need about an 8.5" twist to get reasonable stability at that low muzzle velocity with that long-for-weight bullet. The precision of that stability calculator with .224" bullets are limited, though, so if you work up to a Trail Boss load at about the velocity I mentioned when the chronograph is either on the muzzle or 15 feet out, you want to confirm first that the load groups well from your gun before setting the optical chronograph out at 100 yards. This is to be sure you aren't going to shoot it by mistake. Once you have a load you know groups and has about the right velocity, then shooting the center of the 6" square should not be a problem.