After getting word back from the folks at Barnes who told me with IMR 3031 min load was 21.6Gr, max load 24.6
I tried out a couple of groups using 22.0 grains and got good sub-minute results. Another perk was that they flew nearly the same as the 55 gr Winchester that I had been using at 100m. This weekend I hope to test that load for "target effects"