tops out for structural stability meaning they're ready to blow apart upon contact with ANYTHING above that speed maybe... they go faster safely though. Shooting max loads of H-110 w/ 125 XTP out of a 4'' revolver I was getting rediculous splash effects versus the same loads with berry's plated of the same weight. I never did find anything more than fragments off the xtp's because they literally blew up on 2-liters filled with soapy water... the others just busted them open real good and got deformed.
might be what you need, but then again shooting out of 16' plus of barrel I don't know that a round-nose wouldn't blow apart too. I do know that using 158gr XTP's with H-110 got me MUCH better accuracy and less recoil and blast. I assume that the heavier bullets in the short barrel slowed down the load enough that it didn't top that 1500ish limit and kept the jackets intact.... once again I don't know if that would be enough to help on a rifle though.
the only thing I know for sure is that hornady xtp's WILL open up and violently dump energy into a target, judging by MY EXPERIENCE ONLY it's gonna dump it on the skin if hot-rodded, not in the innards.