If 6500K is best for Veg why are MH lamps 4200K???

Most of the searching I've done shows the majority of Metal Halide lamps to be 4000 k - 4200 k temp range...I had to get a 6500 K MH through a aquarium store. So, if the commonly held belief that 6500 K is better for vegetative growth, why are they so hard to find??? :confused:

Well, you are right, but here is a website that explains...scroll down to Metal Halide...B And for finding the color, try bulbs.com or just look up the type and exact range you want to find. http://progressivegardening.com/plantgrowinglights.html