[MiloXC3]

Trigger, then cylinder and cylinder head.

Have you got a tight bore barrel and new hop up chamber/rubber?

 

[MiloXC3]

Well the barrel and hop up is where most of your accuracy should come from. So if you want to improve that then I'd suggest getting them first.
but, like Wesley said, make your own barrel spacers (this stops vibrations in the barrel) and you could probably try some other modifications.

 

[MiloXC3]

6.03 PDI is a great choice. It will increase your fps a bit too.
Try Tokyo Marui official website, or write on their Facebook page.

On this thread there is a part on making barrel spacers. Ignore all the other stuff about VSRs etc!
www.airsoftretreat.com/forums/index.php?topic=82742.0

 

[MiloXC3]

Wesley, does that mean you have a one-piece barrel and can't take the inner barrel out of the outer barrel?

 

[MiloXC3]

Sorry, I posted that comment before I watched the video. It's a great idea, I might do it to my old stock barrel for some practice!