Sorry Viton seal - should last a lot longer. Apparently.
Today's saga is that the DTI kit - for P38's! Well it isn't quite. Comes with 2 needles inside. Sizes 2 big & 2 small. If the adapter tubes were slightly longer then said long needle wouldn't be too big - it would fit. What this means is that if I try to push the DTI into the tube to seat properly it won't go in because 2 long needle is too long, by about 5 mm but could be a bit longer. Angle grinder time....
The adaptor i have has a short and long pin it works perfectly. But i suppose it could depend on DTI being used.