There is a noticeable improvement, but still a few flyers. If it was throwing them all over, I'd say it was the barrel. But its all vertical, so its the ammo. The barrel looks like it would hold a little over an inch (at worst) if you got the SDs down. Very decent for the price. I did find SK Match (both Pistol and Rifle) had higher SDs than Standard Plus and Pistol Match Special. I didn't try sorting them by weight or rim thickness though.
I'm looking into trying some of the less expensive ammo that performed well at 100 yards in the 6mmbr test. This place has some pretty good prices on Eley and Lapua ammo:
http://www.targetshootingproducts.com
0.622 Eley Club $60/brick
0.753 Lapua Super Club $45/brick
0.831 Eley Sport $45/brick
0.859 Lapua Standard Plus $49/brick