I was out the other day with my Ruger Bisley in 45 Colt, and had it nicely sighted in for the 250 gr cast bullet load I am shooting. When I ran out of those, I started in with the 300 gr XTP loads, and could not put a hole in the paper! After looking all around the target, I saw a cluster of holes maybe 12-14" off to the left - at 25 yds no less. This is the weird part. I know that heavier bullets will most likely hit higher than lighter ones, but I don't know why they would move so far to the left. Incidently, the height of the 300 gr bullets was right on, or nearly so. The windage was just way off. Is this an issue with this particular load, or my grip/trigger pull, or what? I ended up adjusting my rear sight all the way out to the right just to get them on the paper, which is not really acceptable to me because this puts the sights way out of line with the bbl and does not mentally 'line up' right.

Any ideas on what could be happening? I had this same problem one other time when using the 300 gr XTPs, but thought then that maybe the sights were just off when they installed them at the factory. Once I had it sighted in for the 250's, the rear sight was right in the middle of the frame where it was supposed to be. I do have a box of 250 gr XTPs that I haven't loaded yet. I'm going to try them and see how they work. Both of these loads were on the warm side, so the pressures involved should be similar. It's not like the cast loads were cowboy level and then I went to the real heavy loads and saw this POI change. thanks for any thoughts. maxman

That is pretty weird. When I was doing my 454 load developement, I noticed that when I got above 1300fps shooting 340 or 350gn cast then the poi started moveing to the right as the velocity went up, but it still stayed on the target. I would have someone else shoot it to see if it is a function of your hold on the gun. I would think that the 300's would have a higher impact on the target, but that much left is really kind of strange. Maybe try a series of loads in increaseing velocity with the 300's and see what happens???