I doubt the 155's would shoot any more accurate than another Sierra match bullet from 135 to 190 grains in your barrel. But with its 20 inch length, accuracy beyond 600 yards will be iffy, at best. That barrel's not long enough to get enough muzzle velocity to keep them supersonic in cold weather past 600 yards. In warm weather, they may be OK to about 700, but I wouldn't bet on it.
With factory barrels, Sierra's hunting bullets shoot darned near as accurate as their match bullets. Few of us will be able to tell the differnce. Oft times, their flat based hunting bullets shoot more accurate than any boattail bullet in factory barrels. In the 1950's before Sierra made their FMJBT 180 and 200 grain 30 caliber match bullets, top competitors used their spitzer boattail versions in those weights in the finest match grade barrels available. Scores didn't go up a whole lot with Sierra's match bullets when they were finally available. Even after these two bullets came out, many folks used Sierra's 150 and 165 grain spitzer boattails at 200 and 300 yards as they shot almost as accurate as the 180's and even the 168 HPMK"s when it came out.