Try not to disturb the peace.
When wearing a cosplay that involves weapons or military-style gear on the street, be aware of public perception. From the outside, and in the current climate, you may appear as a potential threat. Try to imagine the sight of someone in body armor and visibly armed when you’re headed to the store. Would your first thought be “cosplayer”? Or “Mass Shooter”? I know if my parents saw my Red Hood and didn’t know me, they would be dialing the police.
Be aware of the laws in your local jurisdiction! In most US states, prop firearms should have some sort of colorful tip or markings. Prop blades and melee weapons may also appear to be real. Only brandish them in locations and situations where it’s clear you are part of a photoshoot or con group. Personally, I try to keep any strange props, smaller weapons, and masks in a bag until I arrive at where I’m going. It keeps the non-cosplaying public at ease, and (hopefully) avoid any run-ins with law enforcement.
If you are confronted by law enforcement, be extremely careful: stay calm, follow all instructions, and don’t make any sudden moves. It is far easier to try and explain that you’re in cosplay and that the weapon is a prop after you’ve been disarmed. Quick movements or responding with hostility may make you appear as a lethal threat.
Stay alert, stay safe, and be mindful of others.