Tackebury, I just got some Longshot and will try it. Almost all the data I have seen listed it, so maybe there is a reason. I tried H110 because of the 16 inch barrel, but no harm in trying something new. (NMB=New Model Blackhawk?)
R.W., what are the problems with the 45 mag in a bolt action? That was going to be my next step cartridge wise, so if I can avoid a mistake, I want to know.
Regarding the 450B, I had considered it along with the 458Socom. Do you like it and what do you use it for? I have a 1/16 barrel, rechambering it to 450B would be an option, but would that not be too fast of a twist for the cartridge? The 458 Socom would require a new barrel. I liked the 450 because I could just rechamber the barrel, and the socom because it would keep the same bolt face. In both of these cases, it would be an interesting project, and it may still happen, but my goal for now is still a rifle that will shoot subsonic loads. If i cannot get this barrel to shoot accurately, it will be time to step back and figure out the next step. I am going to try more bullet/powder combinations. If I find anything that works, I will be happy. Any suggestion is welcome. If no combination is satisfactory, I will ream out the throat. If that does not work, it may be time for another project barrel.