O rings that have been subjected to high air pressures will take a shape all their own to create a seal. This means stretching. If those reg o rings have been in use for longer than a week then switch them out for new. O rings are so cheap, the thought of chancing that they’ll reseal just cause they look good shouldn’t even be a thought pattern as far as I’m concerned.
In the end, when the gun is all put back together and leak free, you’ll be glad you threw in brand new half a cent o rings.
And please, do not lube aluminum threads. That streamline is exactly like the wildcat tube guns. The end caps seal with their o rings. If you apply silicone grease or oil on the threaded parts they will sieze up on you. There’s a reason when you first took it apart you never saw any lubes on any mating threads from the factory.
I’ll end this with a tip- if even after installing new o rings your vent hole still leaks(and the o rings inside the reg have also been changed), that means your air tube is overly saturated with lube, which will cause the o rings on the outside of the reg to slip out of their grooves when presdurizex(remember I said they will take a shape all their own).
Remove the reg, end caps, and clean the air tube with acetone. Then take some 2000 grit wet/dry sandpaper and lightly scuff them inside of tube where the regulator nests in inside the tube. Rev lean with acetone.
Only grease the reg o rings and push the reg in place. After the gun is all put together and pressurized, the new o rings will bite better against the air tube sides. Everytime I’ve done this it was a guarantee to not leak afterwards.
And don’t lube threaded parts!! You can’t use petroleum based products in the high pressure air areas, so one would think just use silicone but that is not a good idea, trust me and others in the know will agree.