What kind of bulb should I use for a recessed can?
I have those exact cans and they are adjustable. Take out the bulb and remove the trim.  Inside you will see two or three wing nuts. Loosen these and raise the level of base to the desired location.  If the base is raised all the way up, then indeed your bulbs are too long for the trim you have selected.

Also note that every trim adds a different depth as well.  Trims like eyeball sockets are much deeper and may solve your problem.  I suspect yours is a flush mount one, and thus the distance to the base is shorter.