Sounds like I might do business with Amos in the comming months. To get the whole rifle or just upgrades.

Although, I may want to install upgrades myself. I think if you take something like this seriously. You should know how it works and how to take care of it.

What type of gas can it the KJW take? If I use propane sold at hardware stores, will it cause any damage?

Also, if I shoot indoors and I dont want a gun as loud. Which gas should I use? For that matter, how loud is propane gas?

The hardware store propane is EXACTLY what the KJ's use :)

To quiet down the guns you can throw on a foam filled silencer, it'll greatly cut down the loud "POP" at the muzzle.

If I had a KJ handy right now I'd make a video for you... but they're with other people now :)

I do

The problem with this is that we are not playing with real guns. We have to deal with inherently less accurate and precise "toys".
The difference in skill between the best shooter and the runner up is marginal (at that high level, it's just about who can hold a more still sight picture) at best. That difference is not enough to make up for the inconsistencies of an airsoft gun. It's possible for the runner up to appear to shoot better than the best.

Is this the first time you will have owned an airsoft rifle?
If so, I would not suggest doing the upgrades on your own right away.

The KJW M4 is quite a bit easier to work on then any AEG I have worked on, but going into it blind could be hazardous.

Yes I knowing how to fix it is the next thing on my mind. I am hoping to find reading material about this stuff.

the guy behind the trigger and sights