Just a heads-up....
Legally, you cannot mail (as in US Post Office mail) ammo. It's viewed as hazardous, so if you tell your local USPS what you're sending--they won't. If you don't tell them and get caught....Well, they told me it was a felony, so I didn't.
UPS (as in United Parcel Service) will ship ammo, as will FedEx. I just went through this pain-in-the a$$ process and, frankly, if you're honest about what you're shipping, UPS and FedEx will NOT accept ammo UNLESS you are licensed to ship ammo--They said that means you know how to pack it. Both UPS and FedEx said these are federal laws. I just tried to send someone a few boxes (150rounds) as a gift, but UPS, and FedEx refused the package when I told them it was ammo. It turned into such a PIA, I ordered the ammo on-line and had it sent directly to his address since this was easier.
I know plenty of folks who send ammo UPS and just don't say what it is. And I've sent ammo years ago when UPS didn't seem to give a rat's-a$$ and would just send it. Now, it's a bit more involved if you follow the rules.
YMMV--hope this helps. I'd suggest contacting these shippers yourself to get the info first-hand.