Honing the Air Cylinder?

Deburr the area around the hole for the gauge to go through the tube. It frequently has a razor sharp burr which will slice your O-Rings pulling your gauge block out (or, if you have the Huma regulator with the integrated gauge bock, it will harm the O-Ring on it). Yes to honing the tube where the hammer slides, and deburr the slot where the bolt which goes into the hammer rides into. The air tube itself normally does not leak, especially if you use a good grade silicone oil on the O-Rings.
 
I would not suggest a 320 grit by hand. Sounds like roughing it up or reaming out material, not a true hone. That thing can get away from you causing irregularities that air will find. 

I understand your question but a Sunnen hone for a Springer cylinder is way different. If anything, if I had to mod, I'd follow Addertooth's advice. I debur all O-ring areas with a fine diamond tip file or Dremel. Sometimes just sandpaper on a dowel or thumb just to get that but knocked off. Like a knife edge a bur will bite more than cut. Damage still done.

The actual reg, leave alone. Air gauge block can be ported by an increase of say 25% as I can attest it got my power up in my .22 Discovery. The face can be counterbored & rounded. We're talking miniscule changes but your Chrony doesn't lie. The entire purpose here is deburring so O-ring changes are quicker, easier, not in vain. It sucks to switch em out & find you knicked one.
 
Nico, do you have proper mics & calipers, other gauges & necessary equipment? A lathe would be best but this can be done by hand. I don't know you, just saying stick to a simple debur of end of cylinder if you can. You'll love your Huma. I steered away from regs for a long time. I bought a used RS with an Altaros in it & now I don't think I'd ever buy a new PCP unless it had one or one was available for aftermarket. Good luck! 
 
Nico. I have installed 9 Huma regulators for the guy's in my club, I to was leery of the process but all went well as I followed their directions to the T. I used a small brake cylinder hone available at the local auto parts store on a drill honing the area were the regulator sits in the tube. You only need to do the area were it is going to be. very simple process and you would have to run the hone for a very long time to do any harm as they are not aggressive at all! The inside of the cylinders are somewhat rough from the forming process and all you need to do is smooth it up not remove any metal per say! it will just keep any sharp edges from nicking the o rings while sliding the reg into place. Just be careful not to hone the threads at the end of the tube!! I'm sure like me once you do it you will see it is not a big deal!! Oh ! and clean the tube real well before reassembling and lube the area were the regulator goes in with silicone before inserting the regulator as it makes it much easier to push in to the cylinder!! Good luck and have fun tuning your rifle after the install. J.L.
 
I say just deburr the vent hole-if needed- , should work.

1 time I saw an AA500 that a reg was installed in but it leaked slowly period. After a lot of re-try's and ... ... ..... the air tube was as polished and smooth as a sheet of glass as an absolute last thought the air tube was ROUGHED up . To the point of cross hatching like for a springer comp. tube , reassembled and never a leak since - 2+ years-.

I wouldnt have been 100% sold on that story if I hadnt seen it first hand.

Regulator install is pretty straight forward ( hey hey great times as a regulator no longer costs $600.00 + wait time).

I personally would not do anything extra ( honing ...) untill I dropped it in a gave it a try.





John