I have one of these which looks very similar. I don't use it a lot.
https://www.harborfreight.com/25-liter-ultrasonic-cleaner-63256.html
https://www.harborfreight.com/25-liter-ultrasonic-cleaner-63256.html
I don't know about spray guns at all but I imagine it'll work perfectly. It works very well on gun parts; just remember it will take off everything including the stuff in places you can't really reach so be sure to oil everything thoroughly when you're done or it will corrode in short order.Going to use it to clean internal gun parts and the ocasionally my minijet spray guns.