[dutton]

From the generic pictures I've seen, I'd have to say that parts for the Maruzen APS/ CA M24 are not interchangeable. I'll look around and see if I can find some more detailed pictures and try to give you a definite answer based on that since I've never personally handled one of these rifles.

*Edit*
If you can take a picture of the cylinder assembly - preferable outside of the gun - I might be able to give you a better answer from that.

 

[dutton]

He could get a PDI hopup chamber and an AEG tightbore barrel of the appropriate length, if he really wanted. PDI hopups work in the clones as well as the name brands.

Not based on these pictures, they're not compatible.

http://www.airsoftforum.com/board/post-a4537-.html
http://www.airsoftforum.com/board/post-a4538-.html

 

[dutton]

Alright, from the pictures I was able to find, it doesn't seem like it is APS compatible. My best guess would lean more towards VSR compatible, but without seeing it in person, don't take what I said as fact, it's simply my best guess based on limited pictures I was able to find.