Which nail gun for fencing job?

[Vicky]

Hi,

I've just come across this group today and was wondering if anyone can
offer some advice.
We are about to put up a 2m high close board fence, 14m long. Not a
particulary big job, but having shoulder problems at the moment I
thought I'd buy an air coil nail gun. I have a 120psi compressor.
Looking on ebay I saw a good price on a Rockworth air coil nail gun
firing 25-50mm nails, diameter 2.1 and 2.5.
Since I would be fixing 16mm thick boards to 30mm boards I thought
this gun with 45mm nails would do the job. As I've never actually used
one before I mailed the supplier and asked if it would be suitable for
this job. I received a reply which simply said "Not suitable".
Can anyone please tell me why it wouldn't be suitable, and what would
be. Thanks.