I have been shooting a Delta 10MM for a while and started using Rainer bullets. They did not work too well at the higher velocities. However the HSM bullets worked just fine across the board.
I installed a Kart National Match and then the Rainer bullets worked better too. The point here is there may be 2 variables involved for using plated bullets. The "smoothness" (depth of rifling, bore diameter, rate of twist, ect) of the barrel , and plating thickness. In my case the Colt barrel was pretty rough and the Kart... well is Kart quality.
The HSM bullets seems me to have a harder core of the three Rainer, Berry's and HSM. I could be wrong as I have not scientifically tested just for that.
There sometimes is an alloy added to conduct current better in plating soft metals such as Pb. Higher current means faster metal deposit for plating. (Its a molecular science thing) Those alloys may be some of the "differences" in what stress the plated bullet can take hence the more cautious loading recommendations by the manufacture.
I have been shooting HSM 165 HPs at some pretty fast 10MM speeds with absolutely no problems with excellent accuracy and terminal performance . But then that is my gun and I solved all my variables to do so. Everyone needs to do the same for his gun and load likewise.
Ummm... it looks like that is just what you guys are saying. Imagine that, I understand what I am reading.