It says that 61 gr will give a 150 gr bullet 3,000 fps.

Well with 61 gr, I could only get 2,847 on a 70 deg day in a 24" barrel.

But using 58 gr of Rel 22, I got 2955.

So I'll have to try some more primer and more powder combinatins with the Mag Pro before I set any opinions in stone.

What cartridge and what bullet?

270?