Go for it that's what they are there for, just make sure you post pics of your progress. Once I have it broken down into details and dimensioned I'll post the final version.
I was just discussing the disconnect between 405th forum status and skill today with a friend..
And I think this should be moved to the Weapons and Props section. Like, pronto.
Wiz's work is either stolen from Weta or, well, he's just very, very good. :rolleyes
I have spend many a wasted hour drafting and drawing, working with photo/screen cap references is like trying to solve a puzzle. Since everything is in perspective you have to spend a lot of time studying the reference material and tweaking the drawings. Screen caps from the game tend to be skewed with a very strong perspective (like 28mm), making them a bit tougher to work with in some ways.
Right now I am working on the Assault Rifle. It should be ready for a preliminary posting this weekend.
It is on the "to-do" list, it is one of my personal favorites, but actually Vorgy has already done a great set of bleprints for the Halo 3 Sniper, here is the thread -