@Michael_Hackney Hey, did you got any results?
@Michael_Hackney If you need some more time, just tell me 
Look what came in the mail today… 
(The picture is blurry and doesn’t do it justice - both holes are centered, nice and round in real life.)
The 1.8ID/4OD tube is on the left, on the right I grabbed some PTFE tube that comes with the original Creality 3D hot end just for comparison.
I measured them both, here are the results:
~1.82ID/4.08OD for the left one and ~2.04ID/4.13OD for the Creality tube.
@Rene_Jurack , I’ll ship your sample (2m) with DHL tomorrow.
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@Martin_Klein That looks promising! I am looking really forward to test this!
Meanwhile, I was still busy: I received additional Capricorn Tube from 3 other and different sources now. None of them were provided from Capricorn or E3D like offered before. All these 3 samples are bought with money. And while all previous observations and statements lead to a “faulty batch” I had at hand, what do you think I found out with the new samples? You are right, if you assume that they are also a “faulty batch”…
Sample No. 2: bought from http://E3D-online.com - ID-measuring of ~2.05mm:
Kindly reaching out to @Michael_Hackney and/or @Sanjay_Mortimer1 : Did you got time to take a look at the tubes?
@Rene_Jurack every time we cut off and ship a piece of captube I’m having a small 10mm section cut off and stored. I have a keyence measuring microscope coming in next week, which has fantastic diameter and concentricity measuring ability. I’ll report in when I have data. Captube have reached out to me and are making what seem to be very proactive efforts to try and make good on their promises. I’m reasonably confident that they aren’t fraudsters but are just a couple of guys starting out who are having QC issues. I’ve been there myself, so I’m going to give them the benefit of doubt for now.
@Sanjay_Mortimer1 You don’t do things by halve, don’t you? 
I also think their filled PTFE tube has just quality defects. It is very nice to hear that they are proactive towards you and I noticed today, that they also did a huge overhaul on their website about how they present their “temperature-abilities”. While still being somewhat suspicious (but they try to sell their stuff, you can’t be mad at them for trying), they do state clearly what will happen if one heats their tubes up high. I do very appreciate that and am eagerly waiting for your findings, too. And still, I really want to try a captube, that is not faulty - to give them a fair second chance for comparison tests…