Custom Model Not Rendering In Head But Will In Hand?

I have tried to create a custom armor head item, and it uses a custom 3D model, I've specified the model for the item_model field, and the model when equipped field, here's my code:
  "pools": [
    {
      "rolls": 1,
      "entries": [
        {
          "type": "item",
          "weight": 1,
          "name": "minecraft:stick",
          "functions": [
            {
              "function": "set_count",
              "count": 1
            },
            {
              "function": "set_components",
              "components": {
                "minecraft:equippable": {
                  "slot": "head",
                  "equip_sound": "entity.blaze.shoot",
                  "model": "custom_items/backrax_mask",
                  "dispensable": true,
                  "swappable": true,
                  "damage_on_hurt": true
                },
                "minecraft:max_stack_size": 1,
                "minecraft:max_damage": 60,
                "minecraft:attribute_modifiers": [
                  {
                    "id": "burning_time",
                    "type": "burning_time",
                    "amount": -10,
                    "operation": "add_value",
                    "slot": "head"
                  }
                ],
                "minecraft:item_model": "custom_items/backrax_mask"
              }
            },
            {
              "function": "set_damage",
              "damage": 0
            }
          ]
        }
      ]
    }
  ]
}```

Is there a reason why it shows up as the correct item in my hand but not when worn? Are sticks an unusable equipment item?