The Barnes is about .37, claimed is .369 if I remember correctly. the wounding mechanism between the two is different, Barnes with its pedal opening and Hammer with pedal shedding. Hammer claims a lower minimum velocity, which could extend range on some of my rifles which don’t have the mv of the whelen.It'll be interesting if a tipped .358 197 Hammer can have a better BC by a margin that makes any difference (or at all) vs a .358 200 TTSX. By necessity (.358, 200 gr, mono construction), they need to be similar in form/shape and I personally don't see it happening. Barnes gets their BC from shooting in a 300 yd underground tunnel based on time of flight and are historically pretty close to real world results.
If the bc is close to the Barnes, I will give the hammers a try. Hammer is claiming over .4. I do know that the hunter hammers are only .03-.04 overstated, so these might be right in line with the Barnes. My personal hypothesis is that hammer calculated bc for the bullet shape without taking into account the hollow point. Change that hole diameter and drag goes up. Adding a tip should help.