ClientProxy.java

@Override
public void registerModels() {
	// ...
	registerBlockModel(LWBlocks.SEALED_BARREL, "sealed_barrel");
	// ...
}

private static void registerBlockModel(Block block, String name) {
	registerItemModel(Item.getItemFromBlock(block), name);
}

private static void registerItemModel(Item item, String name) {
	ModelLoader.setCustomModelResourceLocation(item, 0, new ModelResourceLocation(new ResourceLocation(LeatherWorks.MODID, name), "inventory"));
}

LWBlocks.java

// ...
public static final Block SEALED_BARREL = simply(new BlockEmpty(), "sealed_barrel").setCreativeTab(LeatherWorks.LeatherTab);

private static Block simply(Block block, String name) {
	return block.setRegistryName(LeatherWorks.MODID, name).setUnlocalizedName(LeatherWorks.MODID + "." + name);
}