I can't address your Black Max issue with any credibility as I have never had any experience with them.

I have been shooting the Super Slims fora little overmonth now almost everyday. They basically are just a "beefed up" ACC. In the past I have shot the ACC 3-71 shaft with good results but I wanted more weight. I get it with the Super Slims.

I still don't get the hype about the HIT system but I do like the extended length of the inserts; I don't remember them being longer when I tried the axis arrows a couple of years ago. I prefer the G nock with the bushingover the X nock but in all fairness the X nock on the Super Slims is better than most I have seen offered on other shafts.

As far as the diameter goes, the 300's that I am shooting would obviously be smaller than the 3-71. I see that the size of Broadhead Adapter Ring (BAR)Easton recommends for the ACC3-60 shaft is a 7. For the Super slim 300 & 340 they recommend a 5. For comparison purposes, that is the same size recommeded for an ACC 3-39. For what its worth I will tell you that a 3-39 sized uni bushing would not fit inside the 300 Super Slim, it is too big (the bushing). The Super Slim 400 & 500 take a size 3 BAR. That is the same size an ACC 3-18 & 3-28 call for.

Performance wise I would have to give the Super Slims an excellent rating. No different than the ACC shaft but then why wouldn't it be; their specs (weight tolerance & guaranteed staightness)are identical.