I think a somewhat simple way to test whether or not a damage barrel will affect a gun is to get the KD vision item and play with a friend in OMA. Have your friend stand still and shoot them a few times with the non customized gun and record the average damage. Then, do the same, except with the gun modded with the A type barrel, and compare the results. It probably might help, but i'm not sure. I wouldn't mind testing it though, but I don't have any guns that I can customize, and I don't want to buy one just to test it out.