As anyone familiar with the AR platform knows, the rifle is composed of two units known as the upper and lower receivers. These components are held together by two pins known as the pivot pin, which is the pin closest to the muzzle, and the takedown pin, which is the one nearest the buttstock . These pins are held open and closed by sets of pins and springs and are designed so as to easily and quickly separate the receivers for cleaning and maintenance.
On my AR I noticed that the takedown pin was not “snapping” closed. When pushed out, the detent pin was positively securing the pin in the open position but not doing so in the closed position. I started to find that it was working out during long strings of fire. Not good.
I tried drilling the detent on the pin in a little deeper (and marred it a bit in the process) to see if it would help…no dice.
Now this could be for a few reasons. Maybe my lower receiver was out of spec and the detent/spring opening wasn’t drilled in the right spot. Or perhaps the takedown pin was manufactured out of spec.
My options were; buy a new lower, but that seemed foolish as it works fine otherwise, get a replacement pin and gamble that it was the pin’s fault, maybe put in an Accu-wedge and see if the added pressure between receivers would be enough to hold the pin in place or maybe try out one of the various locking pins on the market.
I went with the KNS Precision Push Button Takedown Pin. Made of steel with a black oxide finish, the pin is designed so that when the button is pushed the small “keeper pins” on the end can retract for insertion. When the button is released, the small keeper pins hold the pin in place.
I did my research and a number of users complain that this pin has a couple of drawbacks. One..it’s not “captive”, which means that the pin has to be entirely removed. The original pin was retained by the detent pin/spring and couldn’t be entirely removed from the receiver and possibly lost.
Another complaint was that it was a two hand process to remove the pin. To get it out you have to press on both sides of the pin at the same time. One finger has to push the button to release the keeper pins while the other has to press on the opposite side simultaneously to push the pin out. I did it smoothly the first time. Sure..it’s not as easy as the original, but I din’t think it was a big hassle.
So…problem solved. I think it was the ideal solution for my issue and it looks kind of cool.