M4A1 to CQB what do i need and where?....

So I ordered the CQB version but theres a 6 weeks of wait from Hotspot. The guy said They will be getting the M4A1 sooner so I switched. I want to be able to convert to CQB, where can i buy a CQB outer barrel and inner barrel? and what would you guys recommend? OEM Celcius or Systema PTW?

Thanks

You'll need the inner and outer barrels.

CTW Inner barrel costs $185
CTW Outer Barrel costs $???

You could substitute new/used PTW parts or trade with someone.

I got a '10 CQB Max from Evike and just got an outer barrel extender to go to A1 length for $20.

Why do you want to go CQB, out of curiosity? Do you really play that much CQB? In any case, I find it wiser to just have a CQB upper that you can switch back and forth as needed. OR do what I do, and have 1 long barrel weapon, and 1 CQB weapon!