Why do some impact guns cut off after a couple seconds in reverse?

[skotl]

Per title. I have a Chinese (DCA), Bosch and a dewalt impact gun.

All run in forward direction for as long as you hold the trigger.
The dewalt behaves the same way in reverse, but the other two only run for 1-2 seconds in reverse and stop, meaning I have to let go and re-press the trigger.

I’ve had the DCA for a while and just figured it was a fault, so was surprised that the new Bosch does the same.

Whyfer?

 

[Guzrik]

To not spin the nut off, which always rolls to the centre of the car

Mine at least gives this as an option, which I never use.

 

[Pete.]

To not spin the nut off, which always rolls to the centre of the car

Actually the Makita I was using at work did have that feature. Your post just reminded me. I even put it forward as a control measure for working at height.

 

[BrokenBiker]

My DeWalt will run as long as you have the trigger pulled, but a mates Makita will stop once the hammer stops (I think) then you squeeze again and it spins the nut off, or at least that's how I perceived it to work