From a "newer" TR shooters perspective ; who also shoots occasionally in Open , I feel there are two factors involved between the two disciplines . Wind reading is relevant to both , but gun handling in TR is crucial , as the set-up does make it more difficult to attain that "locked-on" sight picture that seems to be more constant when shooting from a rest . The other is the ballistic differences between the rounds used in the two . You can make esoteric comparisons of different cartridge's , but if you put a low experienced shooter on a .308 TR gun , and then have that same shooter fire another "string" on a .284 Open gun , I'd almost be willing to wager the score on the Open gun will be higher , with a better X count . Why ? The Open gun is more stable in set-up , and the higher velocity round is less interfered with by the same relevant wind conditions . Mainly ; In my own opinion , I think the advancement in powder , bullets , and even primers , along with the fact that TR was the "beginnings" of the sport , and all the testing by shooters , and openly shared information , have allowed the TR shooters to , shall we say , close the gap . It's a long way from a two-legged , rubber-footed Bi-pod to a Phoenix , or a Duplin .