That might be it. Not using the lard attack until after the bullet pattern starts.You're right, you can still do damage to it and it will come out. So I'm not sure what triggers it. For me, it always comes out if I don't use the lard attack, but it might have to do with how much damage you do to it, where you hit it, and when you start firing. Or it's just completely random.
I'll try that today.
I just had another look at my 307mil run where I triggered the dense pattern. I did start my lard attack early but kept it way off to the left of the tank. Far away fom the central gun.
