15 U.S. Code Chapter 76 on “Imitation Firearms.” Also called “look-alike firearms,” imitation firearms are regulated by the U.S. Code, Title 15, Chapter 76 – especially in section 5001.
The relevant part of the code reads: “[T]he term ‘look-alike firearm’ means any imitation of any original firearm which was manufactured, designed, and produced since 1898, including and limited to toy guns, water guns, replica nonguns [sic], and air-soft guns firing nonmetallic projectiles. …
“[E]ach toy, look-alike, or imitation firearm shall have as an integral part, permanently affixed, a blaze orange plug inserted in the barrel of such toy, look-alike, or imitation firearm. Such plug shall be recessed no more than 6 millimeters from the muzzle end of the barrel of such firearm.”
Well it is actually a law, as posted above. It more has to deal with the sale and import of "imitation firearms" not the use of them after sale. You can remove the orange tip legally. You can read the whole code and look up state laws. Some fields might require different things as well. Either way it makes zero sense to have orange tips. It gives people a false sense of security. Criminals could add an orange tip to a real gun. Someone sees it and thinks it is a toy, by the time you realize it is a real gun it is too late. Just a horrible idea to begin with. Saw a news story where people had Glocks with 3D printed housings around them to look like Nerf guns. They legit looked exactly like Nerf guns. Just shows how dumb FEDERAL LAW makers are. Now a criminal can get the drop on someone because they put an orange tip on their gun. People think "toy" or "airsoft" when they see that orange tip.