Well, you certainly joined a long time ago (/sarcasm)! But welcome to the forums, it's always great to have one more member.
The answer (mostly): If you're talking about rigging .X files (maybe even after exporting) then try to find a member named 'Errant AI' (if you're lucky he might post here). He's an EXTREMELY professional gun maker (check the GC Store). E-mail him, and he might just help you.
Yet be-warned: Weapons are very hard to make. You'll notice how few of them there are out there.
-PWP
I've seen it all. Except for myself ever not failing at something.