Just remember it’s probably going to be expensive. I see people complain about shipping rates that places charge on ammo all the time. Those places get discounts that casual shoppers do not.
Well, it's an explosive, you you have to ship it as hazardous. Can the USPS do that?
I guess I'd go UPS, box and label yourself and just drop off at their shipping location (avoiding noisy questions). You probably need an "ORD" sticker or something from the guy at the counter, I'd guess.