I have a Browning T-bolt in 22lr with composite stock (varmit barrel) and a CZ 452 varmit in .17 HMR. I havn't had either long and have only shot/sighted them in once each. I only shot the T-bolt at 25 yards but was very happy with the results. Most 5 shot groups easily under .5 in usually near .3 something. That was with a Leupold straight 6 power scope.
The CZ has a Zeiss 3-9 x40 on it, My best 5 shot group was under 1 inch at 100yards. I started with Hornady ammo and switched to CCI ammo. The best group was with CCI.
I only shot about 25-30 with each brand and am sure my groups will improve.
Back to the T-bolt I started with Blaser ammo and it shot pretty well but my last group was with CCI standard velocity and it was real tight. Actually the only reason I opened the box of CCI was because my last group (7 shots) only looked like a small 3 shot group. I also know where there is a great deal on T-bolts if you are looking. If you have any questions PM me. Cheers Roscoe