item_model wont work for some reason ???

So, i have created a custom armor set, copper chainmail armor, which you can craft. Everything works perfectly, except the ITEM model.
Let's take the boots. The item i'm using are Chainmail Boots, renamed to Copper Chainmail Boots. 
The copper_chainmail_boots.json recipe makes the item have a "minecraft:item_model": "minecraft:copper_chainmail_boots".
The model points to the texture. Why isn't it working like any other item i've hadded so far?
I've tried changing the item to have another model: "minecraft:item_model": "minecraft:coal_candy" (which is another item i've added without problems) and it works, showing the custom texture.
I've subsequently changed the model coal_candy to point to the copper_chainmail_boots.png and that works too.