pin too tight?

[LEKNIGHT]

i have a double star lower, rra lpk, and dpms upper. when i was attaching the upper to the lower the rear pin was so tight. i actually used a rubber hammer to tap it in. not sure if i can just push it out with my fingers like the see in the videos. what causes this? pin just out of spec?

[MasterYong]

i have a double star lower, rra lpk, and dpms upper. when i was attaching the upper to the lower the rear pin was so tight. i actually used a rubber hammer to tap it in. not sure if i can just push it out with my fingers like the see in the videos. what causes this? pin just out of spec?

I've had a tight pin or two on almost every build I've done.

It's normal (though it doesn't happen with all lower/pin combos)

They loosen up after a few hundred rounds. Until then you'll have to tap it in with the rubber mallet and VERY CAREFULLY use something soft, like a delrin punch, to tap the pins back out.

[LEKNIGHT]

oh ok. thanks

[MasterYong]

OH- and also make sure they're not tight WITHOUT the upper on. Something may be outta spec with the detents if they're tight in the lower by themselves (or so I'd assume).

All of my tight pins were only tight when fitting an upper to a lower, but never just in the lower. If the lower is separated form the upper I'd imagine the pins should slide smooth.

[CSACANNONEER]

I had a 50BMG upper custom built and fitted to my lower. The manufacturer likes to mate them tight so, I keep a small plastic headed hammer in the case with it. The upper has no less than 500 rounds through it and it's still as tight as the day I got it.

[missiontrails]

Could be the pin, could be the lower. The only way to tell is with a caliper. Really though, not a big deal, just makes assembly and disassembly a pain for a while.

[bombadillo]

Buy YHM E.Z. Takedown pins. They're much better to use anyway.

[glock_this]

Buy YHM E.Z. Takedown pins. They're much better to use anyway.

+1.. I have rear take down pins on both my builds and have them coming for my 3rd build

[X-NewYawker]

You know, I was watching a show about how that build ARs on the history channel and they showed the workmen using a HAMMER to open both pins on lowers that didn't even HAVE uppers on them.

[wash]

I chuck up my detents in a dremel and round one side with some sand paper.

You don't need a full radius, just knock the corners off and make it smooth.

That makes the pins easier to move. It's nice for a range gun but it's not like they are going to pop out on their own.

[FeuerFrei]

Please don't hammer on it! Swap the pins. Cheap.
Out of spec receiver? Not likely.

[darkest2000]

You know, I was watching a show about how that build ARs on the history channel and they showed the workmen using a HAMMER to open both pins on lowers that didn't even HAVE uppers on them.

after you've assembled 334 AR lowers in a day you'll probably NOT want to use your fingers for anything if you can get away with a hammer what's what you do.

[wash]

Out of spec receiver is not unlikely. I've heard of Stag uppers being machined slightly off so that the rear pin hole can be reamed for a tight fit.

That's kind of a neat feature unless you just want it to fit.

[CSACANNONEER]

Please don't hammer on it! Swap the pins. Cheap.
Out of spec receiver? Not likely.

Why? Lightly tapping with a small, soft faced hammer is the right way to do it. If you can push your pins in by hand, they are just a bit on the loose side. BTW, I have some that are able to be pushed in by hand and some which I use a 2 oz soft faced hammer to tap the pins in.

[spareparts]

I had this situation once. Had to hammer the rear take down pin in and out. Bought an extra pin and same problem. So I lightly sanded down one of the pins until it fit snug but could actually be pushed in and out by hand. Worked fine for about a $5 fix. If it ever gets loose I'll just put the factory fresh pin back in.