There's nothing in-lore to support this, but I've always loved the idea of Gunbreaking being very sweaty work due to all the explosions, so instead of big trenchcoats and heavy boots, I imagine many Gunbreakers favoring gear more akin to a runner or cyclist. Lightweight and breathable fabrics help you stay cool, while removable armor inserts provide extra protection. Gloves and goggles are optional but highly recommended.