So when you rotate an item in your inventory said items keep its rotation. but if you move said item from your inventory to another the item reverts back to its original state. so if you put a rifle that you rotated to be vertical when you put it into a barrel it will rotate back to horizontal witch then if done right will clip tho all the other items in the barrel making it so you can have the rifle take up only 3x3 slots while other items can be in the same slots/over the top of the slots the rifle should be taking.