PDA

View Full Version : pin too tight?


LEKNIGHT
12-03-2009, 7:34 AM
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
12-03-2009, 7:36 AM
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
12-03-2009, 7:38 AM
oh ok. thanks

MasterYong
12-03-2009, 7:58 AM
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
12-03-2009, 8:03 AM
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
12-03-2009, 8:41 AM
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
12-03-2009, 8:55 AM
Buy YHM E.Z. Takedown pins. They're much better to use anyway.

http://yankeehill.bizland.com/store/media/YHM-7285_2.jpg

glock_this
12-03-2009, 8:57 AM
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
12-03-2009, 9:00 AM
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
12-03-2009, 9:13 AM
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
12-03-2009, 10:41 AM
Please don't hammer on it! Swap the pins. Cheap.
Out of spec receiver? Not likely.

darkest2000
12-03-2009, 10:45 AM
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
12-03-2009, 10:48 AM
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
12-03-2009, 10:52 AM
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
12-03-2009, 10:54 AM
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.

wash
12-03-2009, 11:00 AM
I'm fine with a take down pin that I can press out with my finger.

As long as you have to press with a little pressure to get the pin to pop off the detent it should be OK.

Hammer tight is only good if your upper and lower fit together with zero play.

shark92651
12-03-2009, 11:00 AM
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.

I can attest to this. I have a particular lower that has had three different uppers on it and hundreds of rounds through it. I still have to use a hammer and punch to get the takedown pin out. They do not always loosen up over time.

MasterYong
12-03-2009, 11:34 AM
Hammering is no issue IF YOU'RE GENTLE!!! You don't wanna break something, which is in itself unlikely.

If you really want you can try and see where the extra material is (most like on the pins) and you can take a dremel with a polishing bit to it. I wouldn't bother though. Just wait for them to loosen up and they most likely will.

/please be gentle.

coop44
12-03-2009, 12:53 PM
Buy YHM E.Z. Takedown pins. They're much better to use anyway.

http://yankeehill.bizland.com/store/media/YHM-7285_2.jpg

Oh yes thats great, just throw more money at it.

wash
12-03-2009, 1:07 PM
They are on sale...

But any way, I don't see much point unless you've got a top loader and then I think your money would be better spent on a bullet button.

There's nothing wrong with them, but unless your upper or lower receiver are out of spec, smoothing the detents makes it trivial to pop out the pins and you shouldn't need to open it up very often any way.

MasterYong
12-03-2009, 1:16 PM
They are on sale...

But any way, I don't see much point unless you've got a top loader and then I think your money would be better spent on a bullet button.

There's nothing wrong with them, but unless your upper or lower receiver are out of spec, smoothing the detents makes it trivial to pop out the pins and you shouldn't need to open it up very often any way.

You don't open yours to clean?

That's pretty often on mine. Except one that I've never cleaned except with a boresnake. Tryin to see how many rounds it takes before reliability is affected. Little experiment of mine...

wash
12-03-2009, 1:24 PM
I just use good ammo and add more lube.

But even if you open it twice on a range trip for cleaning, it's not that hard.

You could even swap uppers 4-5 times and I still don't think you need extended pins for that.

If you've got arthritis, girl hands or metal hooks, those pins might be great.

MasterYong
12-03-2009, 1:31 PM
I just use good ammo and add more lube.

But even if you open it twice on a range trip for cleaning, it's not that hard.

You could even swap uppers 4-5 times and I still don't think you need extended pins for that.

If you've got arthritis, girl hands or metal hooks, those pins might be great.

:rofl2:

Once the pins get loose from shooting I just use a bullet tip or a delrin punch, whatever I have around, to push the pins out. Once they get real loose I just use my fingers.

The extended pins just seem like one more thing (out of so many) to get caught on something.

bombadillo
12-03-2009, 1:55 PM
You don't open yours to clean?

That's pretty often on mine. Except one that I've never cleaned except with a boresnake. Tryin to see how many rounds it takes before reliability is affected. Little experiment of mine...

Well do tell how it turns out. I see you're near me somewhere too, you should come out to the range sometime!

MasterYong
12-03-2009, 2:05 PM
Well do tell how it turns out. I see you're near me somewhere too, you should come out to the range sometime!

I currently live in AZ actually (never got around to changing my location in my profile here). I'll be living in CA again within a year, but for now it's nice to have AZ residency. :43:

I had always wondered what how much farther norcal is "farther norcal than me", when I saw your location. I've been on the lookout for CG members in Humboldt for a while- there don't seem to be many. I've tried to get friends to sign up but all anyone's really done is made an account and looked around. Would love to see more active members on CG that live in Humboldt- I know there are a lot of gun owners out here, I just fear that those same people are less likely to be online given Humboldt's demographics. Humboldt/Del Norte are very poorly represented here on CG.

I still keep a place in FarNorCal though so I can visit my family- plus that way I wouldn't have to move my furniture or sell it when I moved, since I knew I'd be back in a year or so. Should be back by next April/May at the latest, btu maybe I'll PM you if I'm coming up on vacation. I ususally just go to redwood gun club in samoa.

/threadjack

LEKNIGHT
12-15-2009, 7:28 AM
i think ill try to sand the pin a bit.