I kill all the adds just for the fun of it. I dismantles all the extra guns I had from HoW, because they gave out legendaries like they were candy during that. I'm still still short on weapon parts. Its likely because I'm pretty pick about perks, so if I find a weapon I like more than the one in using, I'll upgrade it and infuse it to ger it on par with my other weapons. I actually don't mind a grind, its just annoying when like 85% percent of my engrams are for armor so I can't get a hold of any weapon parts.