If it had to be a luger it would be a 1939 42 as thats the only one I own
so far as others my choice would be a wheel gun in .357 or larger for reliability and stopping power. If I was a realy big guy [I am not] it would be my raging bull in .454 casull. If the bad guys would line up just right I could prolly get 3 at a time to save ammo!
