A bit more recoil than normal.

If you load heavier bullets in a gun, expect more recoil.

As to the frame, how much difference is there between this gun and a normal Merkel in 9.3 x 74R ?

edit
I found the guns you are talking about. They look fine.
I Would suggest you have a look on some forums in Europe
and see what they have to say (and use Google translation !!!)