Only in degree, not in validity.
Even with a slug, terminal velocity is going to be lower than muzzle velocity, at any angle.
This must be so, because:
- Horizontally, the speed is always going to decrease due to drag.
- Vertically, in order to propel a projectile to a height, you have to overcome the drag to reach that point, that drag will not be lower on the way down, which means the terminal velocity has to be lower.
The only exception is if the impact site is lower than you, and the nozzle speed is is extremely low. That's never going to be the case for a gun.
Of course, the less mass, the higher effect the drag will have for any given shape. So the smaller the shots, the lower the terminal velocity will be. But it will always be far lower than the muzzle velocity.