Moved to the correct forum section.
Post in the correct section, as it'll optimize forum use, which enables us to reply and resolve your problem(s) faster.
NO, "Gear" isn't an essential.
The only things needed to succeed is pretty much a weapon, possibly a few modifications.
You may succeed with other equipment, though this is mainly what's needed.
The M16A1 is decent, though there are obviously weapons out there that are capable of far much more than needed.