I swapped out my KAC bolt carrier for a KAC sandcutter on a Mod 2 CQB.  Rifle will no longer cycle (under gassed).  If I had to guess the carrier key will be the culprit, but I haven't touched a thing as I don't want to void any warranty.  Swap out the sandcutter with the original KAC carrier and runs like a top.  Ammo, conditions, suppressor all that jazz remains unchanged.  

I contacted Knights through their website.  They emailed me back and I was asked to fill out PDF with the option to email back the required info if I was unable to load the PDF.  Tried two different computers updated Adobe the whole nine yards and was unable to use the PDF form so I submitted all my info that was requested in the email.  I waited a week and submitted the same info again.  It has been crickets all the way around.  

Anyone here have any suggestions.  I'm an armor on the M4 platform, but no training specific or through Knights so I don't want to deep dive into this.  I would prefer that they fix this carrier with most likely a broken carrier key screw.  Any thoughts???

I know a guy.
If you don't hear from the returns and repairs email, email me: jleuba(at)knightarmco.com

Thank you both.  Got a reply and off to Knights it goes.  Thanks again for your help gentlemen.

Very cool.

subbed for "just in case."

Strange that some people don’t know who he is lol o_0