OK I had another look at the trailer and figured out from the weaponary mainly that it's bound to be set in the 60's and as such as Big Boss, but let's just call him Snake for now, it's easier.
Firstly, Snake uses a M16A1 rifle, in the bit shooting from the water, and as that weapon is now not used anymore (replaced with the M16A2, but I still don't like the M16
) suggests it set then.
Also goes for the pistol, thank god it's not a SOCOM, but then they can't really use modern guns if it's in the 60's. The pistol looks like a Colt M1911, and aparently a Webly & Scott MK. 1 silencer which was used on the Colt .45 in the Vietnam War. The guards also use the AK-47, not the improved AKS-47U as in MGS2, a notoriously old and obscelete weapon not used anymore.
Secondly, the clothing by both Snake and the guards also look to be from the period, as Snake has webbing (the stuff around his waist) for the M16A1, so same goes for the use of the rifle.
That's all I can think of at the moment, ah my knowledge of weaponary came in sort of handy for once.
