Color is changing

[JakePlous]

Hi, members of the forum, I have a problem with colors
He created a model that uses PNG images, and put the main part of the sniper rifle in green. I made an export, threw all the textures in textures / items, signed the path to all textures in the JSON file, and launched minecraft.
But for some reason, the color of the barrel of this weapon has changed from green to default, that is, to gray.