All these loads are volume or weight measured?

I have shot a lot of BlackHorn and never ever experienced a recoil problem with it. I shoot 90 grains of BlackHorn 209 in my Optima with amazing accuracy. And I am very recoil sensitive. While big as a house, I use a very slight almost loose hold on the range when shooting, so the ignition is a total surprise to me. I get better accuracy that way. And I am very wary of scope eye and rifle recoil. One reason I see some of the 150 grain posts and just cringe. I have shot those loads but did not enjoy it.

I really don't know what to tell you. Other then hold on tight. Maybe try cutting your load. And tell your friend to change scopes. Even a simple Simmon Pro Diamond 4x I think I measured and it has 4 inches of eye relief.