"spysir"The "hydro problem" , with bottles/tanks over 2" dia. is relating to law. If you need to fly with your airgun better ( be open , valve removed and empty) make certain everything is correct ( DOT stamp & hydro ) as the TSA can know every darn reg there is. Sure some people have flow without problem with, maybe not everything "open" . A tube rifle would be under the same rules but you'll not see many 2"+ tubes. And they is a metallurgic reason though when written for the law CF wasn't TOO common, LOL.
Filling at home "I" would want it inspected visually at least just to be safe. I did open my old career when it got 10 years old, coated and clean with a good number duty cycles.
And manuals really might want to state that if any fibers are showing cut, it NEEDS to be looked at by a pro ( fire dept maybe) if not fully inspected.
John