Not being a douche, but have you contacted JP? I know JP put his loads on the website for the 6.5CM and the .260, but I don't think the 6CM is on there due to it's being relatively newer than those aforementioned cartridges.
I've been shooting a GAP10 in 6mm Creedmoor for around 5 years now. Start at 39 gr of H4350 and work up in .2 gr increments to 41 gr. You should find a couple of "nodes" in there.
I've been shooting a GAP10 in 6mm Creedmoor for around 5 years now. Start at 39 gr of H4350 and work up in .2 gr increments to 41 gr. You should find a couple of "nodes" in there.