Yeah, it should be fine.
You might encounter some slight tolerance differences, but nothing a that a quick skim with a file on the spanner pegs won't cure.
Ghost,
You'll be needing one of these:
Barrel nut spanner. Available from all good airsoft retailers.
http://www.arniesairsoft.co.uk/forums/inde...e=post&id=18018
Virtually all the main manufacturers use the real steel esque 'star tooth' Barrel Nut e.g. CA, G&P, G&G, Systema. Quite frankly it is a far better method.
Marui and ICS don't.
Yeah, of course it's Multicam!
From looking at the pistol grip and the fact there is no distinct gap between the RAS and upper receiver I can only conclude it is a shorty 416, obviously not 100% mind.
The 416 is definately issued to Delta/SFOD.
79TransAm,
It's just struck me!
Are you able to get some more info from your brother as to being issued a 10.3" barrel as that is quite interesting? Also he's using an M16A1 Delta Ring.
If you can quiz him about those details it would be appreciated.
p.s. is he using a RIS or RAS?