Can you expand on "primer sensitive"? Had not heard that term yet. I was going to use CCI primers. They are locally available at Bass Pro.
Certain powders show significant pressure and/or velocity changes with different primers in the same load.
W296, for example, does not respond well to "accidentally" using a primer other than what the load was worked up with. Pressures might spike, or drop, depending on the exact substitution. The results are unpredictable.
Unique, on the other hand, is really tolerant of primer "accidents". Pressures don't change much, if at all, unless the load is right on the ragged edge and already near-failure.
I'm not advocating using whatever primer type happens to end up in the reloader's hand when gathering components, but it does add a little bit of a safety buffer.