I'm gonna guess that you cannot get enough Trail Boss in that little case to reach your targeted velocity, but, hey, I could be wrong!

I can tell you what Hodgdon told me about the 500 S&W Magnum when I was loading Trail Boss in that: "Mark the case where the base of the bullet goes and fill it up to there, no more." I followed that instruction and had some sweat shooting loads from a Handi-Rifle.

May I suggest an answer to your problems? Bullseye or AA#2. It will fit the bill nicely. I suppose, although I personally don't like it, Titegroup will too. Large quantities of Trail Boss meter OK but I would think you would have the same problem as Unique in the lower weights. Just me though.

Hope that youngster appreciates what you are doing for them. If they do, it makes it all the better!