You can use a regular micrometer, just use one side of the spindle and anvil as you advance your measurements toward the ogive. I'm not sure about your question regarding measuring the rotational speed of the bullet? That is easily determined by velocity in feet per second against the rate of twist of your barrel.
For example, to keep it simple hypothetically, if your bullet is loaded to say, 3,000 FPS, and your firing it out of a 1 in 12" twist barrel, the bullet would leave the muzzle rotating at 3,000 revolutions per second, or 180,000 RPM, (revolutions per minute). The depth of the lands and grooves of the barrel, along with the length of the bearing surface would have no effect on this. Only the velocity of the bullet itself, and the rate of twist of the barrel it was being shot out of.