I've shot five roe deer in Germany, two bucks and three does. Shot them using my friends guns, a 6.5x54 MS, a 6.5x55 and a 7x65, the latter using solids as that's the ammo my friend inadvertently gave me with the gun. I also saw several other roe deer shot when accompanying others.

The ideal cartridge in my opinion for roe would be a 223. They are a relatively small deer and die easily. Most European hunters, German ones anyway that I experienced, way over gun themselves. Admittedly many do not get the opportunity to shoot many animals so go big in case they fluff the shot.

Shooting from a hochsitz, as many do, is easy hunting and the 223 perfect for accurate placement of the shot. Even on driven roe deer, the 223 will be perfectly adequate to take on these small animals.