KAK Complete Upper Receiver- 300 WSM - 19" Barrel 15" - MLOK

(7 reviews)
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KAK Industry Complete AR10 Upper Receiver , 19" Barrel, 15" MLOK

High Rail Height

• Barrel Length- 19”

• Barrel Material- Stainless 416R Hunter Profile, Blasted Matte Grey

• Chamber- 300 WSM (Winchester Short Mag)

• Twist Rate- 1:10

• Muzzle Device- KAK Compensator 5/8-24

• Gas System- Magnum length

• Gas Block- Low profile .750 Phosphate Finish

• Charging Handle- Enhanced Large Billet Latch

• Upper Receiver- Billet, Modified for Magnum cartridges, uppers are milled post anodize resulting in a small amount of raw material presenting itself on the bottom of the ejection port door, Alumiblack can be applied to cover material if you want to cover this area, it's purely cosmetic 

• Handguard- KAK Industry MLOK 15”, High Quality 6061 T6 Material with Proprietary Clamping Tri-lug System and Heavy-Duty Barrel Nut- Offering the least amount of deflection possible

Weight- 6.5 pounds



  • Auto Profile Carrier Machined from Aircraft/ Bearing Quality 8620 Steel, Properly Heat Treated, Ground to Perfection, BlackNitride Finish by H&M
  • Bolt- Magnum Bolt Face, Headspaced, Dual Ejector, machined from a single piece aircraft/bearing quality 9310 steel, heat treated properly, precision ground, Shot Peened and MPI’d
  • Firing pin is machined from 8740, precision ground, and chrome plated
  • One Piece Billet Fully Machined Enhanced Extractor, Phosphate coated for Increased reliability and corrosion resistance
  • S7 tool steel ejectors and extractor retaining pin
  • 4130 Gas Key, nitride, precision staked using our hydraulic staking machine
  • KAK Carrier Key Screws- Grade 8, Properly Heat Treated

All KAK complete upper receivers are test fired for feed and function using commercially loaded ammunition




300 WSM


  • 5

    Posted by DMJ SERVICES INC on January 25, 2024


  • 5

    Posted by Nicholas Taber on September 25, 2023

    This upper has made me a life time customer of KAK industry! They helped me out with countless questions that I had before I even purchased this and even assured this would fit another companies lower. The lower company is difficult to match with in my experience as it states they don't even match Aero on their website and this was my 2nd purchase to find another upper). I have owned the upper almost a year now and take it shoot quite often. Its definitely got some power from the magnum cartridge but still manages the recoil very well. The rifle was very accurate out to the short distances I have been able to shoot. I love to mag dump on steel from about 100-200 yards and watch the look on everyone's face around me wondering what the heck I'm shooting. My only compliant is the price of ammo but we all know whos to blame for that.

  • 4
    Great Company

    Posted by Matt S. on December 23, 2022

    Shipping was faster than I expected for sure. Received the product I ordered and there was an issue. I contacted customer service who responded right away. They responded right away and sent me a replacement part to fix the problem. Build quality is great and I am very happy with it. Would definitely do business with them again. Customer service was great!

  • 5
    Fine product.

    Posted by Gary B. on December 4, 2022

    Received my order and was pleased with fit and finish. As others have said the upper is fairly heavy so would benefit from a good silent buffer spring with weight. Have not been able to sight in yet but expect no less than what has been found by others.

  • 5
    Pretty happy

    Posted by Chris on August 6, 2022

    Function tested at 100 yards. 5 rounds Norma 180s. 5 hand loads 147 fmj. From 20 round metal pmag. (Only about 5 rounds will fit before they start to shift. Not KAKs problem that's the magazine). No malfunctions at all in the two 5 round strings. I was knealing with no sling and groups were about 1.5 moa. I would expect something under 1moa prone. Is it 1/2 moa? IDK maybe. Looks very nice. Not really light, but balance is OK with a medium weight collapsible stock. May change to a weighted A2 to shift it more rearward. It'll take a lot more rounds before a can really review its accuracy or reliability. But I'm glad I bought from KAK instead of trying to build myself. Seems the magnum gas length is a must. Doesn't seem over or under gased. But it is hard on brass. No worse than a .308win though.

  • 5
    Soft shooter with lots of power

    Posted by Turnkey on February 8, 2021

    I was able to find and use 150 gr federal fusion SP. KAK built an extremely nice and well finished upper. It really does look great. The federal fusion 150's fit great in both metal and polymer magazines. During barrel break in I was able to test metal mag"DPMS/c products", lancer mags and magpul mags. Metal and Lancer worked the best with very little feeding issues. Like the review above commented during break in I polished the feed ramp and this seems to have improved feeding. This upper was able to push the 150's at and average of about 3100 fps started @ 3050 and continued to get faster as the barrel broke in. I am really happy with that velocity from the 19 inch barrel. Accuracy on 5 shot groups single feed was 1/2 MOA @ 100 yards. This upper is ruff on bass and I would take that into consideration when looking to reload for it. I got this upper for taking big hogs around the 600 yard mark and it is going to fit that role perfectly.

  • 4
    Needs better mags

    Posted by Ted on February 18, 2019

    The feed ramp needs polished, I ended up doing that so it feeds/cycles better. I am using a 10 rd 7.62x51 PMag, can't find any aluminum Brownell ones. Of course it could be the mag issue but the polished ramp took care of it. Once the ramp was smoothened it got to feed/cycle flawless. The quality of the build is great! No ejection issues, double ejector is right on as well as the gas block config