Beergun too much O² in bottles?

I've bought a beergun to fill my Beer from the fermentor into my bottles. I got the Feeling that it shoots alot of O² in my Beer. The Beer turned Out super hazy (Not Sure If its because of the gun).

Are beerguns bad in generell or do i miss Something?

I rack from one fermentor to another to leave trub behind and than just fill up the bottles from the dischard.

For my next batch i'll do 50% of the bottles with the beergun and 50% without and See if the gun is the Problem.