Collect all the guns in the game (which can be retained in the Hideout, Not all guns can be). Collect a gun by finishing a level with the particular weapon in your possession. You can take as many weapons at a time out of the level as you wish (you can only carry one rifle at a time).
You can go back and re-do a level at any time, and reply that level as many times as you like, and each time you complete it, any new weapons you bring out which aren't currently in your hideout will be added.
Please note each difficulty settings has its own seperate hideout. You only need fill one hideout to gain the achievement. This can be done on any difficulty setting you wish.
List of guns (with hideout images) and locations - Full credit goes to [TFU]Shakey of the hitmanforums for names and images, locations taken from everyone within the weapons thread stickied in this forum!
- Bull .480 - SLP .40 S
- nub nose - Six shooter - Desert eagle - SLP .40
- MP9 - MP5
- TMP - SAF SMG
- SPAS 12
- Ballers - SMG Tactical
- Elephant Rifle - Kazo TRG
Credit to the stickied post within this forum and everyone inside it
Numerous Levels (The guards in black suits on the level "Requiem" namely)
Numrous Levels ("A Murder Of Crows" being one) Also found on the table when you enter the room to duel with the devil bartender/assassin on the level "A Dance With The Devil"
Numerous Levels ("A Vintage Year", "Till Death Us Do Part" etc)
All over the level "Till Death Us Do Part"
Vinnie in "A New Life" has one
The General (The father wearing a white suit who plays the chello) is carrying one when you kill him on the level "A Vintage Year"
The female target wearing a black guard suit (wandering the map with the walkie talkie on "A Murder Of Crows")
Found on the High Security guards on "A Vintage Year" (one is in the room with the sleeping guard and the guard suit)
Rehab Centre or Manuel Delgado has one in "A Vintage Year"
CIA agents have them, if I got this wrong, Maynard John (The devil bar tender / assassin) has one on the "A Dance With The Devil" level when you kill him
US Army have them in the Whitehouse
CIA Agent (In yellow/gold suit) is carrying it when he enters the lift (It is inside a case) on the level "A dance with the devil"
Sniper (Raymond on "A Murder of Crows" has it, this is the sniper bird suit guy)
Mark Purayah Jr on Murder with Crows has it, this is the guy which recieves the diamonds case
Yellow Feathered Bird Guards in " A Murder of Crows"
Tree House on the level "A New Life"
Sniper on the wall of Pappy's Room in "Till death us do part"
"A dance with the devil" level, found by the table (inside a case, you can just carry the case out with you with the gun still inside no problems btw) with the laptop on which you have to search to get the info