KAK Industry Modified Upper Receiver Assembly - .458 SOCOM
The KAK Industries Modified Upper Receiver Assembly is machined from a 7075-T6 aluminum forging to MIL-SPEC dimensions with a modified port for use with .458 SOCOM or other large cartridges.
Laser engraved T-markings along the top Picatinny rail allow for consistent and repeatable mounting of quick detach optics and accessories. The receiver is protected by an abrasion resistant Type III hardcoat anodized finish.
- Enlarged ejection port
- 7075-T6 aluminum
- Port door and forward assist included
- Laser engraved KAK logo
- M4 feedramps
- MIL-SPEC Type III Class 2 hardcoat anodized
- Machined for .250” takedown/pivot pins
Ratings & Reviews
Good, but some issues
by Jason -
This is a nice upper, and being KAK, I expect it to last a lifetime. That said, I had two issues with mine. 1. The ejection port cover door spring was improperly installed, do the port door just flops around. Easily fixable, but annoying. 2. When these are modified, they mill out the ejection port to accommodate the fat 458 case, but they don't refinish the bare aluminum edge that this creates. I'm not sure why they don't do the milling when all the other machining is done--before the upper is anodized--but they don't. Something to keep in mind. If you have OCD, and don't plan on cerakoting your upper, this might be an issue.
Poor QC and Out of Spec
by USMC Ret. -
Finally received all the parts to assemble my .458 SOCOM. I purchased this Upper from PA back in June. Today I assembled everything and had a an issue with the rear take down hole being out of Spec. The hole is larger than .250. This causes excess side movement between the upper and lower receiver.
<br>Per the previous review. The milled out opening is left unfinished exposing the raw aluminum. Some Birchwood Casey Aluma Black will do the trick. This should have been finished after the milling.
<br>Submitted a RMA for a replacement today. Hopefully PA will replace it. Will follow up.
<br>From PA: We're happy to replace this for you and we apologize for the inconvenience.
Kak 458 upper.
by William -
Only one issue .
<br>Same as other reviews.
<br>The port is reamed out after being coated.
<br>Mine still needs a little more love and attention.
<br>You can see where the tool started cutting and where it finished .
<br>Not a smooth transition.
<br>Even a little black paint afterwards would have hidden the polished metal