By aiming the crosshair at one of your own buildings, and right-clicking, The Rescue Ranger will have you pick up the building (from any distance). The drawbacks to this effect are:
It will cost 130 metal
You will be marked for death while carrying any building
The Rescue Ranger's shots are similar to the Crusader's Crossbow's bolts, both in the way they travel and in the fact that they can heal. Though the RR's bolts only heal friendly buildings. Please note, that while it can heal senties, it will NOT refill ammo, nor will it upgrade buildings, nor remove sappers. While it will not remove sappers, you can use it to heal a sapped building; keeping it alive longer, and granting more opportunity to remove the sapper.
The RR has a clip size of 4, and 16 reserve ammunition.