The absolute best gun ni the entire game is the FAL battle rifle. Power of a small sniper, fire of an assault rifle. If you're a trigger-happy fool, a Military SAW is the gun for you, Just.... Stock up on ammo, and have a SMG secondary, 'cause the reload on it is LAWNG. I have NO idea where to get the .50cal rounds for the special sniper you get for achievements..... I think it's a premium thing. For anyone having trouble with the m79 'nade launcher, you have to fire it at long range for the 'nades to go off. YES it is possible to use singular grenades, but you have to pick 'em up individually....
Still trying to figure this out.... Does wearing a 10-pound flak jacket and 5-pound military-grade helmet actually DO anything for you? Does wearing a full army suit help?