I need this to be .25 (or .308 cal) is feasible (James Perotti did it?). Should I send it to MAC-1 first for the steroid treatment? I need the tweaking and tuning. I do not want this tuner to keep it himself!

I had a .25 Career barrel put onto a QB57. I had hoped to achieve something but its getting dusty with its terrible arc.
I'm hoping this project will fare better.
Any suggestions?
Dafatman31