Upon investigating all the rifles that came here other than what customers have in their hands already- there are no "design flaw" units to be found. As indicated, all the units shipped to us were from the most recent batch from the factory- i.e. original leak issue was sorted out. There is no "spacing" issue allowing leakage.

If a slow leak situation exists, it is going to be the result of a faulty seal somewhere- maybe the cap, maybe the valve, maybe dirt collected in the valve. Just because these are "new" rifles doesn't make them exempt from normal Co2 gun maintenance- i.e. a bit of oil in with the Co2 caplets every so often, and keeping dirt away from the tube/valve. I have two units now sitting as they came, no lubrication added, filled with Co2 and will fire them once a day for the next week or so and see if they lose their Co2 charge. If so- I will investigate further.

Also, my mis-statement on the Co2 cap from a QB- it is the same threading, and the same Bulk caps will fit the XS-60, but the regular piercing-pin QB caps are (at least the newer ones, I cannot find the older one I had floating around) not long enough. That being said, one US seller of rifles and parts is making a modified cap for the XS60C as a "solution"- but as we have seen from this seller on other items- it is a 'solution' for a problem that no longer exists- the QB-type cap is useful from the perspective of eliminating the degasser if someone doesn't like/want it, but nothing functional beyond a different o-ring than exists on the factory rifles.