The 243 really is a great little cartridge for long range. Throw in the 90-95 bullets and she starts to shine. The 6CM is the same thing only optimized for the heavier bullets. There are a couple of LR factory loads out there but it’s really a reloading proposition.
As mentioned above you’re probably as well off money wise to sell the rifle and purchase another in 308 if you’re determined to go 308.
As mentioned above you’re probably as well off money wise to sell the rifle and purchase another in 308 if you’re determined to go 308.