If you do, make certain the address labels are 100% correct.
I work for UPS and just yesterday morning a handgun that was being shipped to a residential address got "tagged" to be held or returned to the shipper.
How'd they find out it was a handgun in the first place? Bad address, went down for an address correction and upon inspection they found a 357Mag inside the box.
Don't know if it's a guy having his handgun returned from warranty repair, if it was a family member sending a gun to him from out of state, or maybe a cross state lines sale without FFL.
Sad thing, the Clerk who found it was under the impression that it is illegal to ship firearms through residential addresses and he thought all firearms had to go through dealers. Though I do live in Ca. so there's a possibility of a Ca. reg. playing in along with UPS policy on firearms shipments.
If I were you, avoid UPS. And if anyone has the links available listing the ATF guidelines on shipping firearms, it would be nice so that way the person asking can print those guidelines up and prove to whoever he's shipping through the regs.