I think you'll find this does not apply to the NPXL. From what I've read a spring compressor is not required for that rifle. The rear cap unscrews and as it moves out it removes the spring preload. Caution - I could be mistaken. I'm just saying the XL series does not come apart quite the same way as the NP or NP2 series.
The XL doesn’t need a compressor. When I had one I had it apart a couple of times. There’s no pressure on the gas ram when the end cap is removed.
I used a beer can when I did mine. You’ll want to find one as thin as possible. It’s a tight fit past those threads. I used some silicone grease on the can to help get the new seal past the threads.
Well I got the new piston and seals for my XL 1100 today.Gonna be doing the tune myself.Does anybody know of a video of that disasembly? All help is greatly appreciated. Thx Rob