You shouldn't! If you're using regular pressure-treated decking, we recommend that you don't use anything but hot-dipped galvanized screws. Nails just won't hold well enough.

What type of decking? example: 5/4 Trex or 1 1/2 redwood. It'll be easier to match the gun nail to the decking rather than guess.
For example redwood & cedar the top choice would be a 16d stainless steel ringshank. With Trex a ceramic coated, hot dipped galvanized or electroplated... and so on

In some locations, galvanized screws (and nails) rust in a few years. I like stainless. Costs a little more, but worth it.

[This message has been edited by rpxlpx (edited July 10, 2003).]