I was on Hodgdon's website looking at the different powders and this is what they have to say about Benchmark:
I've used in my .223s before with excellent results and it's all I use in the 17FB. Is it not a very good performer in 6BR or do people just not bother trying it?
As the name implies, this Extreme Extruded propellant was developed for precision cartridges. As such, it is ideally suited for benchrest and small varmint cartridges like the 6mm PPC, 22 PPC, 6mm BR, 223 Rem. and 222 Rem. Additionally, it performs superbly in the 204 Ruger and with light match bullets in 308 Winchester. With small, easy metering granules, competitors will love how it flows through progressive presses.
I've used in my .223s before with excellent results and it's all I use in the 17FB. Is it not a very good performer in 6BR or do people just not bother trying it?