Being supplied to ukraines. faced with the western weapons, the russians must expect heavy casualties if they expect to move forward using that type of system. reporter: experts say behind the propaganda, they cannot build weapons quick enough, and they are targeting the access to higher target parts, and it is making them harder to manufacturer older equipment, and there are tanks with thousands of them sitting in storage provide an alternative. and a leopard or two or a challenger? this is going to lose every time. but in a wooded or the closer built environments, this is adequate. reporter: it is also simpler to maintain and easier the train on which is an advantage for the mobilized troops. you dig a pit, and then you ....