Pivot/Take down pins too large? Or holes too small?

[SavageEagle]

Wow. So I've been collecting organizing and wheeling and dealing to get here. I get all my parts, get all my mags and ammo, start to build my first complete AR (mostly) from scratch. I got everything but the Bolt Catch and trigger guard on and working... or so I thought.

I took it to a good friend up the street who finds out my extra spring goes to the disconnector... Opps. Trigger assembly was a PITA. I had no trouble, but yet I was missing a spring and the trigger spring was on backwards. DoH. Ok, that's together. We get to the main attraction of the build... The unification. Awww SHEET.

Pivot and Take down pins both decided they don't want to fit. *cringe* they are so tight you have to POUND them to get them to move. Ain't doing that. twist and turn and wiggle, nope.

We can't figure if the pins are too big or the holes, in the upper AND lower (bought in completely seperate states and of different brands), are too small.

Could really use some expert advice from someone. I mean, I was told to just oil the crapola outta her and work the pins until they wear enough to fit right. I suppose I can do that. I'd rather get a second opinion though. Someone who deals with AR's A LOT!

Thanks in advance for the help.


In related news (who got me started on THAT <----), I'm planning on going shooting my new AR and Natalie is gonna come try out her new baby aswell. Anyone interested in a group shoot?

 

[BloodEclipse]

Don't twist them!
Ok I read your post closer. It doesn't sound like you have installed the pins in the lower yet. Do you have the detents and the detent springs?
You need to install these before you try to attach the upper to the lower. If I'm misreading this then help me understand where you are at. Pictures would be helpful.

 

[SavageEagle]

LOL no not twisting the pins, I meant to say pivoting. Long night, sorry. I meant pivoting the upper on the lower.

I did some more inspection of it just now after using some Break Free, It will fit into the lower, but it's TIGHT. Almost need to tap them in. But when the upper is attatched they won't go through. i can get the rear pin to go IN, but not through. The pivot pin won't even try.

I'm suspecting its the upper. I shoulda known better than to buy from a dealer at a gun show that wasn't specializing in black rifles. It's ok. I got the rifle. Just some minor tweaks and I'll be good.

I just need to get some help with this issue and everything else will come my way. I hope.

 

[BloodEclipse]

Ok the pins are installed in the lower correctly then? Meaning you can't pull them out because of the detents. If that statement is true and they work in the lower ok then you should try to attach the lower to the upper with the pivot pin first. Also try taking the bolt carrier out of the upper, if you have a problem with the trigger it might be causing interference.

 

[SavageEagle]

Yes, pins are installed correctly. BCG or no, it made no differnce. Its gotta be the upper. The holes must be too small or something. It all fits up nice and tight. The ONLY issue is that the pins won't slide all the way through. It could just be the pins though. They may be a tad to large.

I can't figure it out and would really like someone to look at it.

 

[BloodEclipse]

If the pins fit ok in the lower than it sounds like the holes in the upper may be undersize. If you look inside the hole when it is together do the pins line up with the holes ok? If they are just undersized they may have been coated too heavily.

 

[r6vr6]

If it were me I'd do the following:
Measure the pins & upper holes with a caliper and compare what you get for readings. If it looks like it should work I'd pull the pins and drop the upper on the lower and see if you have an alignment issue. If the upper holes are a little on the small side I've heard of people taking a bore brush and a drill and polishing the holes a little to get the pins to fit. (could be a finish thickness issue)

I know when my RRA AR was new it was hard to remove the pins but now it goes together with a lot less force. So once you get them in a work them around some it should loosen up.

 

[Colt556]

Take the pins out of the lower and see if they will fit through the holes in the upper. If they fit it's an alignment problem, if they don't fit just carefully hone the holes until they do fit. BE CAREFUL and test fit frequently. You can always take more metal away but you can never put it back! I have a feeling the holes in the upper are to small. It's a good thing, to small is better than to big!

 

[IUalum]

What brand upper and lower?

Some older AR's (colts) use larger holes for the pivot and takedown pins

 

[HandK]

IUalum is right some uppers and lowers take diffrent size pins, I would try just putting your pins thur the upper by itself and the lower by itself, if they fit thur one and not the other then you have a miss matched set.

 

[Kingrat]

i have a noveske upper on a RRA lower and initially the pins were very tight, you could just barely push them in with your fingers or a gentle tap from a screwdriver, no gap between upper and lower,

now that its had >1000rd through it they fit like normal, i wouldnt go much farther than tapping with the handle of a screwdriver, if that wont get em in try putting the upper on someone elses lower (or someone elses upper on your lower) and shooting it a bit it might give you enough play in the holes to put it on your lower

 

[SavageEagle]

If the pins fit ok in the lower than it sounds like the holes in the upper may be undersize. If you look inside the hole when it is together do the pins line up with the holes ok? If they are just undersized they may have been coated too heavily.

Takedown pin holes line up fine. The pivot pin holes are visibly not lining up. I have to squeeze them together HARD and tap with a screwdriver and yet it still won't go.

What brand upper and lower?

Some older AR's (colts) use larger holes for the pivot and takedown pins

Don't remember the brand Upper, but it came from Model 1 Sales for sure.

Lower is a Roggio Purchased at Bradis.

i have a noveske upper on a RRA lower and initially the pins were very tight, you could just barely push them in with your fingers or a gentle tap from a screwdriver, no gap between upper and lower,

now that its had >1000rd through it they fit like normal, i wouldnt go much farther than tapping with the handle of a screwdriver, if that wont get em in try putting the upper on someone elses lower (or someone elses upper on your lower) and shooting it a bit it might give you enough play in the holes to put it on your lower

I hope this is all it is. Just needs broken in.

ANYWAY, the takedown pin went in and out with a little persuasion. It is now in. But the pivot pin will NOT go in. the lower keeps falling away from alignment and the pin will just not go.

Ok, I put the pivot pin in first and after a LOT of Persuasion, it went through. Then tried to put the takedown pin in and noticed a significant amount of space betweent the upper and lower. After some tight squeezign and a few whacks with the butt end of a screwdriver on another screwdriver...... IT's TOGETHER!!!!!!!!!!!!! I think I'll go put 500rnds through it and see where I stand.


Pics to follow.





SO WHO WANTS TO GO SHOOTING THIS WEEKEND???????

 

[SavageEagle]

Everything seems to function ok. Dry run cycles cycle just fine. Bolt locks up, safety works, trigger works, mag catch works, Just the damn pins are in so tight they will have to be forced out.

 

[VUPDblue]

You can take a rat-tail file to the upper holes and loosen them up a bit...

 

[SavageEagle]

Something like this work? It'll fit in the hole and its a file. I just thought it was REALLY hard to file away at the upper? Or is it the lower?

EDIT: didn't realize it was THAT crappy of a pic. anyway, it's a flat upper half and could fit three of them in the hole easy. If I'd had two more It'd be easier....

 

[VUPDblue]

That should work. I've had to do it a couple times.

 

[SavageEagle]

Well, I just Breakfree'ed the whole gun twice and applied to coats of the lube to her aswell. As suggested at arfcom, I soaked that SOBing BCG Like there was no tomorrow! I'll be keeping a can in my range bag aswell.

The pivot still sticks a LITTLE BIT, but It goes in with a couple soft taps from my rubber screwdriver. The problem I now think lies with the Lower. The lower and upper will not meet together without them being pressed together with a good amount of force. I think the pivot pin holes in the lower are too low by a couple millimeters. If this is so, could I send it in and get a tested lower back in a reasonable amount of time?

Anyway, I got her altogether. I'm looking to still get that rear sight. I don't care, flip, no flip, I just need a rear sight. I don't got much cash left for this project and I'm trying to save what's left for range time and training.

 

[VUPDblue]

I darn near GUARANTEE it's the upper and not the lower that's the culprit...

 

[Kingrat]

a little gap inbetween the recievers is normal for many ar15s, also i wouldnt file the holes bigger or anything like that until its been shot, at least a couple hundred rounds will loosen it up quite a bit, mine are perfect now after being a little tight

 

[SavageEagle]

Well, I'm taking it apart again today and scrubbing out the chamber just in case the breefree didn't get all the factory grease and I need to get a boresnake to run down the pipe. I figure as long as I can get it together I'll be ok.

I'm bringing it Sat. to the 1500 since I'll be looking for a rear sight and a couple other things.