Hard to say, the quality of the paint makes a difference. I painted F4 green on my dart and it covered on the first coat. I painted some parts F6 green and it didn't cover until the third coat. What color is the primer? This can affect the coverage also. Your gun can waist paint too. Is it a HVLP?

56 Plaza 63 D100 step side 67 Coronet, 68 Roadrunner, 69 Super Bees, 69 Coronet 500 convertible, 70 Roadrunner Post, 79 D150 360, and a severe case of Mopar a,d,d