Do a search on how to strip the Hw44, I tried to copy and paste but doesn't seem to work for me. It's on the Airgunforum.co.uk. It was really helpful.
It was really not difficult at all.
Remove the moderator/adapter, two set screws
Remove the plastic/polymer shroud covering the barrel (one bolt, two set screws underneath the end of the barrel, slides right out
Remove the grip, (drive out one pin, remove one socket head bolt)
Take out the trigger assembly. It's one piece that just lifts out. I handled this very carefully. I don't know if it comes apart, but I didn't want to take any chances. That gives you access to the socket head set screw that holds the air cylinder. It a tight fit and takes a really short hex key (4mm if I remember correctly) to get to it. I already had one I had cut down I use for hammer spring adjustment on my HW100.
Cylinder slides right out.
Now the fun part, getting the ends off the air cylinder. I really struggled with this when I replaced my HW100 cylinder and started out have the same problems when I started this project. I finally found a "how to" on HW100TUNING that tells you how to do it. I used a modified version of their instructions. I cut a 1.5" piece of sch 40 pvc about 2" long and cut a slit in it about .5" wide and slid it over the cyl and clamped it tightly in the lower part of my vice that's designed to hold pipe (no worries about scarring the cyl this way). I used a long 5/16" bolt with partial threads and slid it through the fill port up to the bolt head to avoid the threads, Hit it a couple of time with a hammer and it broke free fairly easily. You can use an adjustable wrench on the other end, just be sure it fits tightly.
Put the ends on the longer cyl and reattach it to the gun to see how much of the shroud needs to be removed. I used a dremel with a cutting wheel (don't cut to much) and finished with a sanding block. Once finished, take the gauge back off, but leave the cyl screwed in. You can't get to the set screws that hold the adapter onto the barrel with the gauge on and you don't have room to screw the entire cyl back in.
Almost forgot, on reassembly you'll need to sand/grind a flat spot on the bottom side of the moderator/barrel adapter to clear the air gauge fitting.
That's it!
