It appears according to our service terms and conditions, page 7, only 1 firearm per box is permitted, as the wording below says:
"Service for each package containing a firearm"
I read that to mean 1 firearm per box, as each box is considered a package. As in, a Driver delivers 6 packages to an address, they delivered 6 boxes, or items.
This would avoid a claim by a Shipper that they had 10 guns in one box, and only 1 was delivered.
Perhaps turdferguson can verify this?
The Shipper must use Delivery Confirmation
Adult Signature Required
service for each Package containing
a firearm (including handguns). UPS,
in its sole and unlimited discretion,
may require the Shipper to select a
UPS Next Day Air® delivery service
for any Package containing a firearm.
Handguns (as defined by 18 U.S.C.
§ 921) will be accepted for transportation
only via a UPS Next Day Air
delivery service.