I have put gas Rams in Gamos before, pretty straightforward on a gun like that if you can find the ram. My advice is also order a couple of the little plastic horseshoe shaped cocking lever guides as these seem to fall apart pretty easy or break when taking the gun apart. I know chambers has all but the ram, you can probably find a ram on the fleabay. The last one I did on a CFX made the gun a great smooth shooter so worth the trouble.