The proof weight helped but the tuner really made it tighten up considerably.
The stock barrel itself was much better than I expected, the lilja 16.5 barrel was slightly better.
The proof carbon is incredible but also $600 on top of the rifle cost, then add the EC v2 tuner.
The cost result is worth it to me, but I can't speak for anyone else.
I can't argue that the stock barrel wouldn't have been more than enough for 95% of shooters out there, I have gone full tilt down that rabbit hole.