Quality control is rather poor for atomizers (and likely most drip tips). In any case there is a tolerance for the diameter of the atomizer opening and the drip tip, and because they are all made by separate companies the tolerance for the diameter of these accessories is not exactly the same. So you end up with two parts at each end of the spectrum from 2 different companies by pure chance and you will have problems fitting. So its basically impossible to make a drip tip that will fit every atomizer (except maybe if they provided different size O rings).
For an example I have a 510 drip tip that would barely squeeze onto the first bauway atomizer I got. Got some more bauways and it fits all of those just fine (still gets stuck on that first one though).