Please explain, as the two have virtually identical case capacities. I ask because I too have been thinking about the 6.5mm RM lately.
I took some H4831 and filled a 6.5-284, 6.5-06, and 6.5 RM to the mouth of the case.
Roughly, I could load 7 more grains of powder in the 6.5 RM than the 284 case and 5 grains more than the 06 case.
For the velocity I want, around 2,900+ or so. You have to push the 284 case hard. With the 6.5 RM case you can do it with lesser pressure, and, you can load the 6.5 RM case up to higher speeds closer to 264 win mag if you like with less recoil.
I think RM case more flexible.
Nope, A 7RM won't get there...but in a 28" barrel it will drive a 180 to 3100. 26-27" barrels run 3020-3050 pretty consistently.
Would you care to share some of the loads that would take you above 3000fps with a 180gr in a 26" barrel (including OAL)?
I can tell you that I had TMR build me a 7mm RM with a Brux 27" 8.6 twist barrel for 180 Bergers.
I could never get 3,000 mv out of it. I tried Retumbo, RL25, 7828 ect. Never could.
He may have had a lot of Retumbo that could get him there. My keg couldn't.
I also found it easier to go 7STW with a 26" barrel than 7 RM with a 27" or 28" barrel in trying to get 3,000 mv. No dif in recoil between the two as my shoulder told me.
btw, Travis is a heck of a rifle-smith!
