Just thought I would let you guys know a little on my own research with the .223. I know there was a post earlier about this and just thought I would share my experience.
Went out calling last night and had a nice coyote come in to about 100 yards. This would have been about the extent of my .2 mag range, but luckily i had the .223. The coyote was facing us and i hit him just off center in the chest with a FMJ. The bullet made a tiny hole in his chest and came right out his hind quarters with another tiny hole. Both of these holes were barley the size of the bullet.
So we will still have to seen on foxes but I assumer it would do the same. If the bullet didnt expand through a whole coyote I doubt it would expand going through a fox.
Also we calling in a lynx later that night. Came out on the field about 400 yards away. Would be a tricky shot with the .223. Cant wait until Decmeber 1st.