A 338Win can shoot very accurately out of a 20-22" barrel. It is very common to do what he is doing. In my opinion, barrel length has very little to do with accuracy to a point. Has to do with powder burn rate and consistency in doing that, the thoat length, the smoothness of the barrel, the round of the crown. Just an opinion. I mean, you can't expect to have a 1" barrel and get accuracy.