This 100ml model has no grub screws. It was held on the 3D printed mount with nylon tie straps. The caps screw on the central part and tighten against o-rings on each end. I never messed with it. The model was fully built by the Lighter Side of RC and was a good flying aircraft when I got it.
It some how cracked on the way from my house to the field. It was perfect before I left. No fuel was leaking. Just so weird.
I used this brand of air trap before with good success. I don't want to knock it.
I order a replacement barrel from Aero Panda. I was worried about taking it apart but it was not tight at all, perhaps because it was broken.
I'm sticking with it, because its way less work to install the same and the inside of the airplane is so nice. A MAP UAT may be better, but way uglier - LOL.