Howdy!
I usually use Mr. Surfacer 1500 grey primer, which always leaves a very smooth surface. However, on my current model I wanted to use white primer as the base color is going to be very light. The only white primer I had on hand was Zero White Primer, which I had never actually used before.
I did notice the stuff is pretty thick, but is supposed to be airbrush-ready. I had to shoot at 30-40 psi and I stayed about 2 - 3" from the model. After several coats, the surface has a pebbled look and feel, not at all paint-ready.
So, did I shoot too dry, too thick, etc.? Or, is this just how this stuff works and I should be ready to wet sand it?