Rear take down pin loose

[13F3OL7]

I put together my first AR-15 yesterday and everything went well with one exception, the rear take down pin. With the pin, detent, detent spring, and receiver end plate installed the pin is loose enough where it will freely move to the right if there is no pressure from the upper receiver. Would that be an issue with the pin being the wrong size or is it more likely that the detent spring would be kinked somewhere in it's channel? Advice on what needs to be done to correct it would be greatly appreciated.

[rhewitt]

Well the only way to find out is to take the buffer tube plate off and look at the spring. My guess you don't have the right spring or you have kink it in some way. What I have found when I work on other people’s rifle like this is that they forgot to put the detent in.

[Iraqgunz]

That's what I am thinking. Either something isn't seated right or the spring is incorrect.

Well the only way to find out is to take the buffer tube plate off and look at the spring. My guess you don't have the right spring or you have kink it in some way. What I have found when I work on other people’s rifle like this is that they forgot to put the detent in.

[13F3OL7]

Thanks for both replies. I'll check again this afternoon when my boys are taking their nap.

[Quib]

I’ve pinched and kinked a Takedown Pin Detent Spring before during a Stock installation. It’s pretty easy to do if you are not paying attention during assembly of the Receiver Extension, Receiver End Plate, and Castle Nut.

[August]

I’ve pinched and kinked a Takedown Pin Detent Spring before during a Stock installation. It’s pretty easy to do if you are not paying attention during assembly of the Receiver Extension, Receiver End Plate, and Castle Nut.

Me too, sadly.

Is the channel of the pin to the rear of the rifle?

[13F3OL7]

I finally got around to taking the receiver plate off to check the spring and couldn't find a kink anywhere in the spring at all. I tried out three different detents, springs, and takedown pins. They all still allow the rear takedown pin to slide out to the right of the lower receiver, being stopped by the detent before it falls completely out. All of the takedown pins I tried wiggle around in the hole. Not entirely positive, but I don't think that's supposed to happen. Any ideas on what I could or should do? It's the only thing stopping me from taking it to the range and zeroing my irons and red dot.

[Quib]

The Takedown Pin should have a hole the detent sits in, in the closed position. See if this hole was left out of the machining process. If it is present, it might be too shallow. Try taking the appropriate sized drill bit and making the hole slightly deeper.

[rhewitt]

well it sounds like you have a out of spec lower if your rear take down pin is loose even with a detent and spring in. If you have everything in like it supposed to. You have an oversized hole. Now I remember about two years ago I ran across a company that was making them like that cause they wanted you to use their LPK. But you can see where that went. They didn't make it very long. But I would have to guess if you got the detent and the spring in like you need to then your lower is out of spec. Who makes that lower that you got??

[13F3OL7]

It's a Territorial Gunsmiths lower such as the one in Rob's lower comparison thread else where on the board. An email has gone out to Sully and I'm waiting on a response, but don't expect one before Tuesday since it is Labor Day weekend. I have another lower at my FFL, but cannot pick it up to compare the two as he is on vacation for moose hunting season.

I'll try the trick with the drill bit on the takedown pin a little later after the wife and kids have gone to sleep.


ETA: At Sully's suggestion I found a drill bit that fit inside the channel for the detent and spring, chucked it into my drill, and slowly moved it in and out. It worked like a charm and I no longer have any problems with the rear takedown pin moving freely.