A 22-250 has got speed, but its a little light for deer, unless you role your own. The 220 swift you can kill deer with but if you dont have the right kind of bullets, you have to head shot them. Aand unlees your swift is almost dead on, you are gonna miss a lot. I would try and use something a little bigger. A .243 is a great gun for deer, but as little light for larger big game animals like elk. Try and see if he roles his own for the 22-250 and tell him its not recommended for the swift. But something like a .243 or bigger will work great.