Thanks for the replies.
I called UPS and the operator I spoke with told me that I could not ship ammo unless I had a specific hazmat contract with UPS to do so. She kept insisting that I cannot ship ammunition. I aksed to speak with the hazmat dept. directly, she refused telling me again, that I cannot ship it unless I have a specific contract to do so and daily pickup for that purpose. I insisted once more to speak with the hazmat dept, she said they probably will not take my call if I do not have an account with them. I demanded to be transfered....she finally put me through.
I was told, yes, I can ship ammo; and no it is not a problem to do so. Ammo must be under .50 caliber and the box weighing no more than 66lbs. It must ship ground. On the box must be clearly written "cartridges small arms" and under that a black rectangular box inside which is written "ORM-D". I must personally drop the box off at a UPS drop center. That's it.