I had a go at fixing a np02 as it was leaking in the fill probe area and had no success getting the end block off, went as far as I dared clamping the cylinder in a vice and even bent the bar that was lathe made to Fit the fill port trying to get it unscrewed. Gave it a bit of heat and it made no difference so they are well put together just hope they never have to come apart!
Saying that I do have a puncher breaker and it’s quite a nice bit of kit for the money.
Founder & ex secretary of Rivington Riflemen.
www.rivington-riflemen.uk