Are you talking about the 138 harness or the 138 bag assembly? I've havn't tried the bag assembly, but the tactical harness (the one that the crypto can be carried with, works great, not to mention you can carry 3 batteries in the bottom aswell)
If any of you are wondering why the 522 can't fit properly into it's harness it's because of the battery adapter plate, the batteries that we now use in our 522 arent' the original design some of you have seen the larger black battery I assume? well that was the original battery, and that would fit sug as a bug in a rug into the harness along with a spare battery. But those batteries had a tendency to explode so they managed to power the 522 using 2 138 batteries, but an adapter plate had to be used, anyway where I'm going with this is the battery adapter plate is the same with as the 138 so therefore that is why the 522 fits into the tactical assembly for the 138.