1. I stripped myself totally and put on a +7 Calf Python and Lighting Sphere
2. I tried auto attack to the Dummy Lv100 in the Asgard Training Ground. It works fine. Shown in the picture below.
3. I cast Crimson Marker on the Dummy Lv100.
4. I cast Dragon Tail. I got a skill failure shown in the picture below. "Please equip the proper ammunition first."
5. I switch to Purified Bullet and recast Crimson Marker and then Dragon Tail. It works as shown.
I also tried all the other Spheres. All of them not working with Dragon Tail.
Only Bullets works.