just some quick things since I don't have a lot of time right now:
I set the UV map to use material IDs, and the end result was a bit better (obviously things need to be packed in a bit more):
you can go that route, it seemed to produce some ok results. I like to take each element and unwrap it manually tho, just because you have more control that way and make sure that nothing is warped etc. sometimes when you do it with a script like that it produces some undesirable results on the tricky shapes because it cant find the best way to unwrap it.
I realized that all those small parts that are floating around are due to things like this:
I think that's more or less a result of what I'm talking about. that shape you're showing seems like it could be unwraped as just its own object. Those individual faces shouldn't be unwrapped individually (I think that's what you're talking about)
About the packing. Idk if you've really gotten into it yet but a lot of those pieces could be overlapped. the small ones especially that don't take up a lot of pixel space (so it's hard to put anything distinct on them.) You can overlap things that are going to have more or less the same texture that won't be noticed and that are small. Looking at the relative size of those parts they may barely take up 1 pixel on the texture sheet. Better to overlap them when you can and then scale them up a bit at the end to fit them in between the spaces of the more important elements.
generally speaking; you should have relatively little of those tiny tiny pieces as they aren't going to be noticed much on the model and they're almost useless on the texture sheet. Obviously it's a product of modeling to have those tiny pieces lying around, but best go over the model once more and see where some of them can be eliminated (while still maintaining the shape) or where they can be attached to other elements on the UV map to create a larger piece that will see more pixels.
also, as a note, looking at the model it looks like there are a few faces that aren't going to ever be seen.
the face behind the guns come to mind. There looks to be a few faces that will never be seen on the model that you could do with deleting. That will save you some texture space for other things and obviously save on tris in the end. I'd go over the model to tune it up a bit before packing the UV.
These are just some things I noticed. I'm by no means a great modeler but I've seen my fair share of feedback:
http://www.realitymod.com/forum/f388-pr-bf2-community-modding/121511-wip-fmk-1-fmk-3-mines-pr-f.htmlalso I don't mean to come off harsh if I do, I'm just pointing out some things. The model actually looks really good, so it deserves a good UV and texture.
Btw in that thread alone Rhino posts at least 15 'mini' tutorials on modeling, UVing, tips ticks etc... the guys knows his stuff and he helped me out a lot with that first model. there's a lot of learning that can be done in that thread alone.