kwa m16 barrel replacement
 

if anyone knows how to install a tightbore on my kwa km16 battle rifle please help me i have know idea how to do it?

Perhaps you should bring your rifle to someone who knows how to do it.

If you've never taken your gun apart you might want a little live guidance.

It is one of the easiest "upgrades" to do as it doesn't involve opening the more complex mechbox. Try searching youtube or go to mechbox.com. Taking the upper and lower receivers apart the first time can be a little difficult as the tolerances on higher end guns is less (nice tight fit).

I have the KWA M16BR and I put a tightbore in it; Prometheus 6.03 509mm.

A picture is worth a thousand words, so search for a video that at least shows how to get the upper and lower receivers apart. When swapping out the barrels be sure not to lose the little nub that is an important part of the functioning of your hop-up.