Just to clarify a bit...
Obviously it is impossible for a projectile to have zero wind drift. If it spends any time in the air at all, it will drift with the wind.
There's a chance (and probably quite a good chance actually) that the new cold hammer forged BSA barrel results in a more stable pellet in flight and a better ballistic coefficient. A more stable and more efficient pellet will spend less time in the air, and as a result will drift less with the wind.
You don't have to sit down and do subjective tests, guessing at the wind speed or shooting side by side with another shooter at the exact same moment etc etc..
You can conduct a very simple test, that will give you a definitive answer to this.
Exactly as Conor suggests - Chrono at the Muzzle, Chrono at 50 yards - use those results to calculate the BC and from the BC you can calculate how long the pellet spent in the air and will give you an answer about whether it takes less wind than another rifle/barrel/pellet combination.
The highest measured BC for a JSB 8.4 variant I've heard of is 0.027, the lowest I've personally measured is 0.018 but I have heard of 8.4's that are lower than that.
If the BSA barrel can achieve a higher BC than 0.027 with 8.4's then it will be better in the wind than any other gun on sale at the moment. Which would be a real step forward in airgunning!