WGP Sniper 3

Well, here's my current marker, the Sniper 3. I purchased this off of a previous owner who took it to the field twice and left it sitting in his closet. It needed a lot of cleaning and lubing when I got it. I've got an Aradus barrel on order. I'm curious as to how it will work.

Talk about rare with a fairly low serial number (3436). I have a hunch this was made from 95 to 97. It has the old style metal trigger frame with hinge trigger.

So here's the specs on this gun:

Future mods I'd like to make to the gun:

 

Why a Pump?