hello fog. I have no idea if the new ct apvs have the new or old switch. . If that is the old switch, the brass screw is solid. make sure to engage the side of the tube with the switch. In otherwords, depress the switch from the side and not smack dab in the middle. I'd send a ticket to ENS if you don't get more answers. I've never heard of a copper screw. Could it be gold plated? If so, it is definetly not solid gold
If that is the new switch, with the delrin cup, you will need to use more washers.
Thank you Tybin. The CT is part of the Zenesis 2 system and it has the new switch with the Delrin cup. I took a second look at the screw and it's gold plated. As it's dark yellow so I took it for copper last night. My fault...

Do I need to use more washers than the two I have in there now? It is working fine.
I just solved the issue with the gap between the switch and tube. I turned out that I had the tube upside down with the grooves at the end of the carto. With the grooves at the switch side the switch closes tight on the tube. Great!
@joaquingt I have red AW 490 batteries.