Loose rear take down pin

I was going thru my one and only carbine as I will be shooting it this weekend for the first time in forever and I noticed the rear take down pin is quite loose... as in it will not stay in the gun once I start it with a punch and push it out.
It stays in "on its own" when I shake the rifle downward and when I run/manipulate the bolt and other controls most vigorously. The gun has a collap. stock/comm diameter.

1. What is THE fix going forward?

1. What is the intersection of quality/value fix going forward?

2. What is a field expedient fix between now and the weekend?

Thank you all in advance as I am at the edge of my lane in the carbine realm.

DB

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Originally Posted by vcdgrips

I was going thru my one and only carbine as I will be shooting it this weekend for the first time in forever and I noticed the rear take down pin is quite loose... as in it will not stay in the gun once I start it with a punch and push it out.
It stays in "on its own" when I shake the rifle downward and when I run/manipulate the bolt and other controls most vigorously. The gun has a collap. stock/comm diameter.

1. What is THE fix going forward?

1. What is the intersection of quality/value fix going forward?

2. What is a field expedient fix between now and the weekend?

Thank you all in advance as I am at the edge of my lane in the carbine realm.

DB

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Did you change the grip and possibly bend or lose the spring that pushes up against the pin?

Highly likely re lost spring.

I agree that something sounds funky with the spring and detent, but on a typical AR, the detent for the takedown pin is retained by the receiver extension retainer plate, not the grip. Did you change the RE recently? If not, the culprit is possibly a substandard detent (or pin) that has worn down.

However, a field expiedient fix would be tape.


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As others have said, either a missing detent or damaged/ broken detent spring. Has anyone ever removed the RE or end plate for anything? Often time, the spring will get bent if not careful.

Can you hear the detent sliding around if you tilt the rifle fore and aft?

OEM grip came off years ago and replaced with an Ergo grip.
Stock has been swapped out. Agency single point sling mount put on years ago.
My best recollection was that rear take down pin would stay on place just like the front pivot pin by the magwell.

At the expense of being trifling, I suspect I will tape it in place with some gorilla tape and get it to an armorer after this weekend if not before.

Pop the castle nut and have a look at the spring and detent. Whatever is going on, is going on in there....

I wouldn't call it a gunsmith issue yet. I would leave the grip alone, it has nothing to do with the takedown pins if we are talking about a standard lower. Pull the stock off and remove the castle nut and receiver end plate. Pull the rear takedown spring and detent out and inspect. If all appears well, place the detent back into it's hole and follow with the spring. Use your finger to apply pressure to the spring and see if you can get the takedown pin to tighten back up to your preference. If you cannot, replace spring, detent, and possibly the pin. Re-stake the castle nut when you get done.

Thank you all. Got to the Armorer this am at the PD. The collective opinion re the interface between the spring/detent/receiver plate was spot on. Thank you all.