The Collection System is a feature in Ironsight that allows players to acquire (with a few exceptions) Rare and Epic Weapons as well as special attachments specific to them, only available through using the system.
Weapons are obtained by owning the Uncommon, Advanced and Special weapon shown in the Collection menu when clicking on the desired weapon, or clicking on "conditions" when viewing the weapon in the Loadout menu.
Once all required weapons are obtained the collection weapon in question can be purchased like any other weapon in the Loadout menu at no additional cost.
Attachments can be unlocked after the associated weapon is in the player's inventory. The weapon does not have to be acquired via the Collection System, it only needs to be in the player's possession. If a weapon, usually found in the Collection System, is obtained through other sources (e.g. Influencer Packs), it's corresponding attachment can still be unlocked. Once the condition is met the attachment can be bought just like the weapon in the Loadout menu for no additional cost.
The Collection System also houses weapons that don't have the same characteristics as the others, namely the
Cobalt Weapons. These Weapons are of Advanced rarity, have no attachment relating to them and require only Common weapons to be unlocked. The Luxury Old Man Laser Sight is the only attachment to be unlocked by a weapon that isn't part of the Collection System, namely the Luxury Old Man AK-47, which can be acquired in the Holiday Box.