I figured that out with a cheap gun that I bought from the autobody supply store, I needed to get the nozzle off to clean behind it but man was it tight. Asked my supply guy he said yea it has to come off I guess, so with his blessing I clamped the gun in a vice and with a good 6pt box end wrench I bore down til it broke free. Was definitely glued in with some form of locktite, paint flows behind it to get to the nozzle so it's obvious it needs to come apart for cleaning, well the loctite is impossible to clean off the threads, my time is worth much more to me than what it would take to fully clean those threads and make it serviceable. My supplier gave me a refund and I got a finex gun that I love but I started noticing all the low end guns that were made exactly the same. They all have a thick plastic piece behind the nozzle, many different brands and grades of guns but any with the plastic piece behind the nozzle has the nozzle glued on. As for me that makes it a one use gun whether it's a $10 purple gun or a $70 cheap gun from the autobody supply house.