The real thing is very hard to get, but thanks to CLUTCH PRECISION, I was finally able to get my hands on the KA4 upper rail. Compared to the real thing, it is made with great attention to detail, and I am very satisfied with it. What's more, it's not too expensive, which is nice. The only drawback is that it cannot be installed unless you rub it together. I was able to assemble it successfully by rubbing the rail part of the product rather than processing the upper receiver, but I felt that it might be better to leave a little more clearance.
However, apart from that one point, there is no doubt that it is a very satisfying product.
I can confidently recommend it to users who can adjust the rub-in themselves!
