|A gun tap as it exits a through hole. Notice the way that those chips are going.|
Tapping with a gun tap is typically easier since you are not trying to work the chip up through the flutes. I think that is why people like them. As long as you have a deeply drilled hole, and don't mind a bunch of shavings being compressed into the bottom, I suppose that's alright. But we all know it's WRONG!
If I could only fill my tool box with one type of tap, it would be standard. Why? Because a standard tap doesn't care if the hole is blind or through. The gun tap is meant to work with only one type of hole.
I doubt I will EVER get done explaining this to people.