All Machine Guns collected and displayed in Hideout
For this trophy to pop you need to have all 3 Machine Guns on display in your shed. All Machine Guns except the SMG-SD6 are concealable. See All Firearms Collected for an enhanced explanation for collecting weapons.
SMG (0:54): The best place to get this weapon is in Mission 6: Tracking Hayamoto. It is isolated in a small room just West of the kitchen - where you place the tracker to complete your objective - and down a corridor. It is the first door on your right.
SMG SD6 (3:17): The SMG SD6 is easily obtained in Mission 8: At the Gates as this level has lots of isolated guards who carry this weapon. The two most convenient opportunities are either: The guard right at the start who patrols on the bank to the right of your starting point or the isolated guard patrolling the fenced off area where one of the generators is – which you need to go to in order to complete your objective. Kill either of them and take their disguise along with the gun. The disguise is kind of redundant in this mission, because the guards still come over and check your ID which may result in your cover being blown. The only good thing about the disguise is it protects you from being shot at by the snipers. Also, when you start the following mission, you are at liberty to drop it.
Uzi (5:07): This can be found on all the Cult Members (Orange Outfit) in Mission 18: Terminal Hospitality. The best opportunity to get one is the isolated guard who is standing stationary next to the swimming pool, near the Agency Drop Off Point. From the level's starting point, head West passed the crates and up the bank. Take a right through a narrow gap leading to the swimming pool. Change into the cult member's disguise and then shoot the stationary cult member in the back of the head, no one will hear the shot. Take his Uzi and make sure you hide his body in the temple behind you, otherwise his body will be found. Because this weapon is concealable, you are at liberty to change your disguise.
i've been playing on professional and had the uzi and smg in my hideout. after finishing the game and doing mission select, i replayed shogun showdown and finished the level with the smg-sd6. i now have all three weapons on display in my hideout and the trophy did not pop. do i need the m60 as well? (the description says machine guns and not sub-machine guns and this could be holding me back from unlocking it)