Nozzle too small diameter

Hi, I was wondering this is an issue for a Velleman ticket?
I bought a new nozzle, did the heater block around it and tried to fasten the setscrew. The block didn’t clamp enough, could turn the block around the nozzle. Fastened the screw more, but without result. I got two measurements. The original nozzle:

and the new one:

It seems to be a slight difference but apparantly enough to leave the block loose.

After that I replaced the old nozzle and it turned out that I had fastened the setscrew so much that the screw thread of the block is broke now. So I have to replace the heater block too!

Velleman, can you please give me an answer? Thank you in advance.

@velleman, be a sport and let your light shine on this issue…