
The specific cosmetic update in Call of Duty: Modern Warfare 3 that has sparked controversy is related to the transgender flag. As part of the Season 4 update, Activision offered free Pride cosmetics, including seven different Weapon Camo variants representing the colors of different LGBTQ+ flags. One of those camo variants is the transgender flag. When applied to the M4 gun's "Soul Harvester" weapon blueprint, it not only paints the gun in the flag's colors but also applies the flag's design to the texture on the ammunition cartridge, making the bullets appear to be in the colors of the transgender flag.
This update led to a series of misleading and transphobic claims by right-wing influencers and conspiracy theorists, who derided Activision for adding "trans bullets" to the game. Despite the fact that the colored bullets only appear when applying the transgender flag camo to that specific weapon blueprint, the controversy has been used to fuel baseless and harmful narratives about LGBTQ+ people.

Some of the prominent social media figures who have contributed to spreading the controversy about the "trans bullets" include Call of Duty leaker BobNetworkUK, Twitter account InsaneCope, Mark "Grummz" Kern, Ian Miles Cheong, and the account Libs of Tiktok run by Chaya Raichik. These individuals and accounts have either shared or commented on the issue, with some deriding Activision for adding "trans bullets" to the game and others spreading transphobic conspiracy theories.

The appearance of the "trans bullets" in Call of Duty seems to be an unintentional result of the game's complex shader system interacting with the various skins and cosmetics. It appears to be isolated to one specific skin on one particular gun, the M4 "Soul Harvester" blueprint. When the transgender flag camo is applied to this specific skin, the bullets in the cartridge change color to match the camo. This effect is not replicated with other weapons or skins, suggesting it may be a bug or an idiosyncrasy of the game's design. Activision has not commented on the issue, referring inquiries to the original Pride Month section of its season 4 update.