Wandering along the edge of a wooded area on a beautiful sunny and cool (-15) day, I was pleased to find these oak galls on the twigs of a young sapling Bur Oak. From reading I have done, it seems that these are often called "Oak rough bullet galls" and are made by a Disholcaspis quercusmamma wasp in the Cynipidae family.

There are many types of galls on oaks, one of the most distinctive is a spiny one on the leaves, also on leaves is the so-called oak-apple gall. Most oak galls are made by a species of minuscule Cynipid wasp (Cynipidae family). Either something has found the larva inside and extracted it, or more likely, the holes you see are the exit holes of the wasp.