[wesley810]

I would actually keep the stock chamber, rubber, and polish the stock barrel and put it back in since it's a Marui. They are known for awesome stock hop-ups.

I'd go for a trigger if you're wanting to up the FPS any more than it already is. Definitely get some barrel spacers also (I'd make my own).

 

[wesley810]

You can also make a full barrel wax spacer, although it's a bit tedious. You need the make a spacer that won't leak and put that towards your hop-up unit, wrap the inner barrel in teflon, and then begin to pour melted wax inside the outer barrel. Make sure to pour a little, and then screw the barrel cap on to make sure the inner barrel is centered, and let the wax cool and then repeat the process. I learned this from some guy on youtube; here's a link of him doing it:

 

[wesley810]

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

The guy is saying to wrap the inner barrel in teflon tape and it will allow you to slide it out when needed. I haven't actually tried this yet though; I was going to a long time ago, but ended up buying a G&G Heavy Barrel for my KJW. It seems like it may work, you may want to just wrap a section in teflon tape, and pour some way over it and let it dry to make sure that it will slide out.

 

[wesley810]

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!

It's all good man. Somebody else on this forum also recommended spraying the inner barrel with some WD-40 and then spraying some expandable foam in the outer barrel. It seems like it would be easier to remove if needed, but little pieces might flake off into the barrel.