Re: 6 mm Remington Problem!
Not having any experience with the slightly larger version, I have found a couple of powder which work extremely well in the .243 with those weight bullets.
Both H4350, and H1000 gave me top end velocities with the 95 - 100gr loads I have tried. These are both in the Extreme line and I haven't notice much if any differences in performance with temps ranging from 34 up through around 95 degrees.
The last loads I worked with have been with the newer Hybrid 100V which is showing great promise. It also looks like it puts up respectable numbers for the 6mm as well.
I don't know if you have any of the first two mentioned powders on hand or have access to them but if so I would give them a try if so. I highly doubt that either would let you down. I would go for the H4350 first as it will push the lighter weight just a tad faster and give you slightly more filled capacity than the load your currently using. The H1000 should work as well and will give you a full case compressed load with either bullet, and just slightly lower velocity with the lighter weights.
I have used H4350 since they brought it out and found it useful and very accurate in several calibers. It might not always get the last fps from a load but it is always consistent and does give very decent velocities across the board.
Good luck with your loading, and hopefully this helps.
Mike / Tx
"Heck why would I lie, most folks don't believe the truth when I tell them"