(5 reviews)
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KAK Industry Modified AR15 Upper Receiver For 458 Socom

• Upper Receiver- Precision machined Forged 7075 T6 Aluminum

• Matte black hard coat anodized Mil 8625 Type 3 Class 2

• Modified port for use with 458 Socom or other similar large calibers 

These 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 care to cover this area, it's purely cosmetic 


Upper ships with Ejection Port Cover Installed

Forward Assist Included  


  • 5
    Beautiful item!

    Posted by Brian on September 29, 2023

    I absolutely love these enlarged upper assemblies! I built 3 using these and I'm very happy with the price and quality. Perfect fit with my Aero Precision lower assembly!

  • 5
    Beautiful item!

    Posted by Brian on August 14, 2023

    Very pleased with the quality and price! Beautiful fit!

  • 5
    Great upper for big bore carbines

    Posted by dkurtz on June 2, 2022

    Worked great in my AR45 build. Most of the other parts were from Stern Defense and I was going to get their 'enlarge port' upper as well but the KAK was much more affordable and I liked the idea of a 458 opening. If you're going to go big then go really big. Please note the upper comes stripped so you'll need to add your own forward assist or plug as well as port door. Regular old mil-spec port doors will work and this upper has a nice feature of having a small hole for your port door spring, so it doesn't stick into the enlarged port opening. Not even the Aero XL had that, and did I mention this is more affordable than the Aero as well? Yea, it's great value. The new Magpul port door didn't fit very well, as in it had some slop/play in it, but I think that's a result of the Magpul port door, not this upper. A standard mil-spec one fit the best. KAK has always been great, would buy again

  • 5

    Posted by Ben on October 19, 2020

    Tolerance is tight where gas tube enters upper. Had a gas tube that had a wee nib on the outside for some reason. With a low pro barrel nut, no issue. With a strike ind handguard nut, had to lightly file for 13 seconds, makes me feel good that the upper was machined correctly, and wanted to keep redirected gasses, redirected!!

  • 5
    Great upper

    Posted by Jose on July 29, 2020

    Very neatly modified upper to enable the mammoth shell to extract. I especially liked the tiny burrhole drilled in the receiver to accommodate the ejector door spring. Nicely priced, too.