I would argue that the BY15 - Red Action is the rarest gun skin in the game. Here’s why: Season 1 battle pass went to 100 tiers. You got the AK-47 Red Action at tier 100. (If you bought the battle pass). The BY15 and DLQ Red Action were only unlock-able through crates. You could eat these crates in the battle pass as rewards (paid not free battle pass). So you have a random chance at getting either or both. So they were the rarest gun skins. However, they re-released the DLQ Red Action in a bundle. That means that the BY15 Red Action is now the rarest gun skin.