Nail gun driver doesn’t return after firing

No -- an 18 ga. nailer is ideal for attaching small pieces of trim, like shoe molding/quarter round, inside your house. Outside, the nails will quickly rust and fall off -- they aren't galvanized, they are TINY, and they have little to no head on them. If you want to use a nailer, you need to use a framing nailer like Shirlock suggested. Make sure you use hot-dipped galvanized nails.

Personally, when building a fence, I use coated decking/exterior screws. They won't allow boards to warp and move like nails will, they absolutely won't ever rust unless you stripped the coating off somehow, and if you need to replace a fence plank because it cracked/warped/discolored, or you need to repair storm damage, or you need to remove an entire run of fencing to get a pickup truck or a large piece of equipment into the backyard, you can just unscrew a couple of screws. I haven't used nails for fencing in several years, and I've been happier as a result.

The plastic contains Volatile Corrosion Inhibitor (VCI) molecules that are adsorbed onto the metallic surface, protecting the metallic surface by forming a film. The Zerust FAQ claims that the inhibitor “passivate the electron flow between the anodic and cathodic areas on metal surfaces and interrupt the electro-chemical corrosion process.”

Zerust products for storage are advertised as being effective for five years, but I would expect them to be effective for a much shorter time in a toolbox that is frequently opened and used. You may find numbers in the specs for their military products.