One of the first things to consider when making weapons is UV mapping, a high poly model like that will be a pain in the ass to texture. For one thing, that's definately more than 500 polys, more like 1000 - considering the barrel at the front looks like a 40 sided cylinder, with 4 sections before it meets the gun - your talking about 320 polygons on the barrel alone!.
I suggest you forget the idea of texturing after modelling and come to a happy medium that will let you work faster and be in better control of polygons. For example, instead of using umpteen polys on the barrel, make 4 x 8 sided cylinders and stick them end to end, just like you have, an extruded polyline makes for a good gun too, cylinders and extruded polys is usually all you need. I like to lay out the model as if it was a texture map before texturing, like on the handle, you could vertice edit the sides so they're flat, then plain map - after you'd plain mapped, you simply re-edit the vertices back into shape - beats trying to UV map those tricky bits. You can usually get away with cylinder mapping the barrel, but lay your model out with plain mapping in mind, you'll notice how much easier it makes things - and how much easier it is to avoid texture stretching. Never take a whole gun mesh and plain map it with a photograph like a lot of people do, it's on screen all the time so pay close attention to the top of the gun, keep that clean and the model will look great.
Personally, I would'nt usually go above 400 polys on a hand gun, of course it depends, but as a rule I like 8 sided cylinders for barrels, which keeps the poly count down quite nicely without looking like crud.
Van-B
