[1.9.4] Loading OBJ for a block

I'm trying to load this OBJ file (961 bytes) from Blender 2.76b and apply it to a block. However, it silently does not render. The block is currently untextured as I want to get the model in the game before worrying about details.

In the client's preinit, I use the following:

OBJLoader.INSTANCE.addDomain(DataModInfo.MOD_ID.toLowerCase());
Item precisionLaserTurretItem = Item.getItemFromBlock(ModBlocks.precision_laser_turret);
ModelLoader.setCustomModelResourceLocation(precisionLaserTurretItem, 0,
        new ModelResourceLocation(DataModInfo.MOD_ID.toLowerCase()+
        ":precision_laser_turret_head.obj", "inventory"));

Under assets.turtletech.blockstates, I have the following in precision_laser_turret.json:

{
    "forge_marker": 1,
    "defaults": {
        "model": "turtletech:precision_laser_turret_head.obj",
        "uvlock": true
    },
    "variants": {
        "inventory": { "model": "turtletech:precision_laser_turret_head.obj" },

        "facing": {
            "north": {},
            "east": { "y": 90 },
            "south": { "y": 180 },
            "west": { "y": 270 }
        },

        "active": {
            "true": {},
            "false": {}
        },

        "powered": {
            "true": {},
            "false": {}
        }
    }
}

And, I have placed precision_laser_turret_head.obj and precision_laser_turret_head.mtl in both assets.turtletech.models.block and assets.turtletech.models.item.

I could certainly use some suggestions here and can upload any files necessary.