AR15 Takedown pins problem, help please.

[Barang]

Thanks to all who encourage me to build my own ARs (2 for me & 2 for my wife) and finally finished all yesterday.
2 ARs are perfect but the other two are having problems with the takedown pins.
One would go 3/4 in and I have to pound the rest through. The other would go 1/8 in and I have to pound the rest through. What is the remedy? Thanks in advance.

*** UPDATE: Post #31 ***

[hammerhands32]

Shoot it. I've had pins super tight before but all it took was a couple of trips to the range to loosen everything up.

Otherwise you are stuck with lube or trying to polish or sand them down a little bit if they are that far out of spec.

try the uppers on different lowers as some uppers just don't fit quite right on some lowers.

[tanakasan]

As mentioned, try and mix/match uppers to see if some fit better. Sometimes you need to put a small chamfer on the rear of the rear take down lug corners. The square lug hits the rounded contour in the lower. Look inside for any marks.

Robert

[ocabj]

Don't do anything to your lugs. Just use a rubber mallet and/or delrin punch to move the pins when you want to separate your upper/lower, until the pins start to loosen up. The pins will wear in after a short while, and eventually, they'll be loose, and you'll probably come back into the forum and ask about how to tighten them up.

[Barang]

I'll follow the advice given. Thanks guys.

[SureShot241]

From my experience, sometimes there are minor burrs in the pocket that the pins go into, and can be anodized over. Also, I have seen some pockets (tubes) that somehow got flattened in some way inside.

Just make sure to check the pockets, because you might not need to modify the pins.

[Bansh88]

"pound" is also a relative term. Needing some assitance from an object is normal. If you're full on beating with a hammer and piunch, something could be off.

Years ago I had a Henderson Defense lower that turned out to be out of spec. 2 differnt uppers did not line up. I MAY have been able to pound the rear takedown in, but it was not right. They refunded my money as they had no more and knew of the issue.

[FIREBALL_BRIAN]

use a reamer. run it in by hand and check that way.

[AeroEngi]

Just keep the takedown pins lubed and keep pushing them in the way that you're doing now. It'll eventually wear in so you won't have to "pound" them in anymore.

[FeuerFrei]

Thanks to all who encourage me to build my own ARs (2 for me & 2 for my wife) and finally finished all yesterday.
2 ARs are perfect but the other two are having problems with the takedown pins.
One would go 3/4 in and I have to pound the rest through. The other would go 1/8 in and I have to pound the rest through. What is the remedy? Thanks in advance.

You should never have to pound or force the pins in. Ever.
Use a 1/4" drill bit and see if things line up first. By hand only from the safety switch side. Insert blunt end of bit.
This will tell you if there is an alignment problem or an obstruction.
If an obstruction you can apply lube and turn the bit to fix it.

Good luck.

[GreaterFool]

My spanking new Colt AR had same issue. After i took it out to the range to zero it and after 200+ rounds everything's smooth like butter.

[jpx0123]

I've seen that issue with the colt as well. I added oil to the detent pin and spring area. lubed up the pivot pin surface. I also found out an interesting thing. I usually put the upper on the lower and then push the take down and pivot pin in. but on the colt the pivot pin (front one) does what you described OP. but if I pull out the rear take down pin and pivot the upper off the lower, then the front pin goes in and out normally. maybe that will help your issue too.

[glock_this]

I would never pound them. That is not the kind of stiff effort you should encounter. If you check the holes and find them out of spec, there is your answer. I suppose you could have out of spec pins, but less likely. AND, you could have an out of spec rear lug or pocket the lug slides into - I have had this issue. IF you have to alter and if you have to pound stuff with a hammer, but as was said "pound" effort is relative and can make all of the difference in what you do here as it could have been written more extreme than it really is, it could be time to alter. If you have to alter, consider altering the cheapest part. That means, in this case, your pins. But look close at your reag lug and pocket and see if when you close the upper the lug is making a mark on the side walls of the pocket.

Are these 80% lowers by chance as that could make this issue clearer.

[Barang]

Just got done mixing/matching uppers and lowers and this what I found out:
1- All 4 uppers are good to go.
2-The FDE lower is starting to loosen up just by pulling the pin in and out so it's no longer a problem.
3-The Hello Kitty theme (flat top receiver) lower is still a problem. Just to clarify the word "pound", I use wooden dowel to hit the pin with the handle of screwdriver.
After inspection, I found out that the holes are just a hair smaller and I can see black scratches on top of the holes. So, I'll make some alteration tomorrow.

Thank you all for chiming in.

[JDay]

Are the detents installed correctly?