I attached a pic with that shows what I mean.

Most weapons that see frequent use tend to look like this. They're cared for but even the best of cared for items eventually start to show wear. Unless constantly polished they loose a bit of that shine and reflectivity and pick up scratches and wear marks from use.

Unless you're going for a weapon that's been grossly neglected I'm sure you can get this look with a specular map. I think the goal would be to break up how light/reflections bounce off the surface of your model.