I was wondering if anyone would bring up the pressure excursion issue.
If you knew.... I don't know how many hundred rounds of 7 RM I've CHRONOGRAPHED... they're all recorded.....
I've seen NO spikes in velocities that would catch your attention. The 'fastest' burning powder I EVER put in a 7 mag case is IMR 4350 > then IMR 4831 > then Surplus 4831 > Now Rl 26.
I have NO idea of 'what' powders gave the pressure spikes..... I did not find one.