I would appreciate any help in identifying these cannonballs.I was given these by my neighbor who got them from a friend who found them inside a tree he was cutting down. One appears to be steel, rusty, and has a #4 cast in the top and weighs 9lbs. The other has the markings ,5-45 k 103mm weighs 12 lbs and has a plug which looks like it could be removed [ I didnt try to remove it]. They are approx. 3-3/4'' o.d. Does anyone think they know what these are?