I was doing a question while back about finding the de Broglie wavelength of a bullet with a given mass travelling at a given speed- easy stuff. However, when the result was very similar but slightly larger than the Planck length which I'd stumbled across on my few jaunts through Wikipedia, it got me thinking. If the Planck length is the smallest concievable length (according to Wikipedia, we haven't covered it as such in lectures), and a normal day to day moving object has a de Broglie wavelength smaller than this length, is there actually a de Broglie wavelength at all? Would quantum phenomena cease at this point? I would be intrigued to find out more from someone who knows more than I do about quantum physics. Thanks and sorry in advance if I've posted this in the wrong place!