Here's my checklist to determine if it is indeed out of round.
1. Measure from 12 o'clock to 6 o'clock.
2. Measure from 3 o'clock to 9 o'clock.
Is there a difference?
Often times there is, and the builders typically use 1/16th of an inch as a threshold. This depends on the manufacturer.
3. Have you examined the head? Where the collar of the head joins, there is sometimes glue residue or aluminum protruding which creates a not-so-smooth application and removal. This is also a good way of determining if it's the head or the drum that may be defective.
4. Have you tried different heads? Each brand of head has a different collar, and they sit on drums differently.
Something else to note: Snare Beds
Snare beds are 2 channels that are indented across from each other just under the snare drum throw off, and just under the butt plate.
These beds vary from model to model. The builder determines the width and depth of the bed to best serve the sensitivity of the snare wires.