I want to pull this back up to let everyone know: While you might be lucky and have
your first loads do just what you want, most of these 300/221's are very picky.
I do not want anyone to say that if you buy an XYZ barrel you can do this, because, that may not be the case. You are going to have to play with the loads and speeds
to get the gun shooting. It is a lot more so with this round than with any other round I
have ever loaded for
What you are going to end up with is one or two loads in the
supersonic that will shoot, and probably only one or two loads of subsonic that will
group like you like. I have also deduced that the crown of the barrel on this round
is the most critical single element that will make and break a load. If you don't believe me, buy one and come back and say WTF
And while it has been fun, I am still not
where I want to be[BD] I still have to pull out my Savage Tactical or AR10 to lob a couple down there just to make sure it is not me
when I get through trying loads.
ETA: You may not want to get too near the speed of sound to optimize your subsonic load