I bought the following from KAK to assemble the upper you see in these pictures:

* OE-SPEC 5.56 AR15 Barrel- 13.9", Chrome Lined Phosphate
* AR15 MLOK Handguard - 13"
* Assembled AR15 Upper Receiver
* STEEL .750 LOW PROFILE GAS BLOCK NITRIDE KIT
* MID LENGTH GAS TUBE
* K-SPEC-S Enhanced AR15 BCG- 5.56/300 Blackout- Full Chrome, Downvent, Single Ejector Bolt
* BIG LATCH CHARGING HANDLE
* A2 BIRDCAGE Flash Hider w/ CRUSH WASHER- 1/2 (not used)

I decided to use a SilencerCo ASR Closed-Time Flash Hider instead of the birdcage flash hider so I could mount my Velos LBP 556K suppressor.   
  
The grand total for this upper build was about \~$600.  
  
I threw this upper on a lower that I built out using only Geissele parts and it looks great. I haven't tested it yet but I know it is going to buck.   
  
Let's be honest, for a duty grade upper, $600 isn't a whole lot of money and the quality of the parts are chef's kiss perfect. It took me about \~20 minutes to assemble this upper this morning before work. I spent more time taking out my tools and putting them away than it took to assemble the upper.   
  
The full chrome downvent BCG is slick and I was going to put in a gas defeating charging handle in but decided not to because I actually like the mil-spec big latch charging handle from KAK. Besides, the downvent BCG and flow through suppressor should be enough to not gas me out.   
  
My first encounter with KAK was when I was looking for 9" 300 blackout barrel and I opted to buy their Mr. Blond 9" 300 Blackout barrel which was pristine and runs flawlessly using supers and subs suppressed. I don't know what black magic KAK uses to make their parts but they are some of the best I have come across in my years of building AR15s -- especially for the price points. 

The handguard is impressive for \~$100 and the assembled upper has a beautiful finish on it. I couldn't find one tooling mark on it. The barrel is also very nice and BCG blew me away. 

I am so glad I found KAK and have been pleasantly surprised with every product that I have purchased from them. On top of all that their customer service is top tier.   
  
People go on and on about BCM being the gold standard but I think KAK is right up there with them. They are an absolutely fantastic company making high quality parts for avid builders such as myself.   
  
I am so looking forward to taking this bad boy to the range this weekend and running it hard. 

What are ya'll thoughts and experience with KAK? Do they align with mine?

Let's Talk About KAK