First look before any shooting of the 2018 rubbers.
Here you see them fit on the most common and suggested barrels:
There were speculations that these won’t fit on PDI. Well, those were wrong 😀
However the window ends are angled, but the cut out is technically the same size as Lambda, and just a little smaller than SBA and ZCI (~0.5mm)
The improved contact surface nicely fits in all of them.
They also changed the way the rubber seals around the nozzle, the inside of the lips is slightly angled inward. Thats a clever way to make the fit tighter without increase the outside diameter. It will work flawlessly on spring rifles, will also try on aegs.
Since these are one piece rubbers, the contact surface and sealing parts made if the same material, that will require a bit more carefull assembly. That makes a bit concern to use Lambda and ZCI, those windows are 90° milled and pretty sharp, SBA barrel has a slight ~5°(?) angle, that seems safer, for the first test I will go for PDI, that will be the safest option.
If you use fast chamber make sure you won’t pair a barrel and a hard nub which damage the rubber.
Here is a quick visual representation: