Re: 7mm LRM
There's a fair amount of info on the cartridge on here. It's a staple for the Gunwerks guys, and you can buy brass and dies from them.
I don't own one, but the standard expectation I believe is 3050fps on 73.0 gr of H1000 for Berger 180's out of a 25.5-26.0" barrel. I believe that is a little better than your average 7-300WSM.
You will see quotes from the Gunwerks guys, that it is very similar to the 6.5-284 dimensionally, and it benefits from the same case capacity to bullet diameter benefits, therefore providing improved efficiency.
I bought worked over 700 in 7STW planning to re-barrel to the LRM, but found it shoots 168Bergers at 3120 extremely well and with a LOT less felt recoil than I expected, so the plan is still on hold. I will say that while Gunwerks markets the brass, the limited accessibility of brass would be a concern, it is even a problem on my SAAMI STW.