It may not be too bad as long as you aren't shooting from the bench. I have a Ruger #1 around that weight in a custom cartridge that sits between the .458WM and .458Lott, it's kind of snappy. Have you seen the new Trijicon Accupower 1-8x? I know you have a Swarovski but these look really good.

As and aside, I thought GMA closed up a few years about?