I've shot thousands of Berrys and quite a few Rainier bullets. I use jacketed data and except for the lighter bullets, I go up to 90% full load(many have been 100%). As long as the velocities are under 1200ish I don't worry about the plating comeing apart. You do have to use common sense on working up the load and watching for any sort of hint of issues as the charge goes up of course.I also watch my paper targets for extra holes that would be a sign of the plating seperating,over-crimping is the most detrimental to the plating than velocity.
Acually in .357Sig, some of mine are getting up in the 1300-1350fps area with no "issues", so they are plenty safe at the 1000fps that you are looking at.
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