I think I am going to add about 3/4 inch of length to the length of the CZ 550 stock for the 505 for several obvious reasons--
I have a long LOP and the CRF bolt withdrawal distance for the ~4 inch cartridge is quite long!!

The red line would be where your approximate EYEBALL position is on the stock with the CZ 550 bolt back!! Looks like your head must come off the stock abit with working the bolt!! Don't wanna "poke your eye out"!!