View Full Version : Receiver jiggle
longrange18
05-28-10, 14:49
I was just wandering if receiver jiggle bothers anybody else. I know it doesn't cause any function problems but I just can't seem to shake the feeling.
If I had the ability to try out different uppers to see if they mated well I would but there is a lack of stores around me that carry stripped upper receivers.
Let me know your thoughts....
Longrange
Belmont31R
05-28-10, 15:07
Then choose another platform. Just how AR's are, and I personally can't stand pins that are so tight you need a punch to get them loose.
It used to bug me, when I first got into ARs. But I told myself to stop worrying about it, and stopping deliberately twisting the rifle to feel for it. Now I don't even notice it.
Its one of those things that if you let it bug you, it will drive you crazy on what is a perfectly fine rifle.
You just gotta let it go. The rifle is exactly the way it was designed to be...
It is part of the inherit design of the platform to have a little play b/t receivers....if you run a vfg up front, this tends to accentuate the play due to the extra torque you are putting on it.
Mil spec is absolutely not a science and unlike most people think, its impossible from one batch of ARs to the next to have them machined and finished to the exact same standard everytime....same as the ano on the recievers, sometimes its perfectly flat black, than sometimes its a shade of purple.....sometimes your receivers fit tight, sometimes they fit loose..
If it drives you that mad, try a accu wedge....contrary to what many people think, they will work:)
sonrider657
05-28-10, 16:00
If it bothers you just give your gun a wedgie (http://www.brownells.com/.aspx/pid=16662/Product/AR_15_M16_ACCU_WEDGE).
http://www.brownells.com/userdocs/products/p_993150100_1.jpg
If it drives you that mad, try a accu wedge....contrary to what many people think, they will work:)
I highly advise against it.While it will take the slop out, they can become dislodged and cause problems. I am not saying that it is guaranteed to do so, it does happen. Why risk a potential problem to fix a minor annoyance that has no effect on performance.
Accuwedge and lower reciever tension screws are the oppsite of what you need... Think about it. The slop is because the upper and lower at the rear take down pin typically have play at the pin - creating space between the mating suraces that allows the movement - so the proper fix is at the pin with something that pulls the upper down onto the lower, not pushes it away. This can be accomplished by drilling and tapping the rear lug at a 45 degree angle to the lower recievers top side and insalling a small set screw with threadlock agent. (once the propper depth has been set to put downward tension on the upper & takedown pin) The setscrew tip or nose should be rounded to allow the takedown pin to wedge inbetween the screw and the lower without catching on the setscrew. I will post some pics for clarification later this evening. All of my AR15s have this mod to keep things tight and keep myself sane. :)
Accuwedge and lower reciever tension screws are the oppsite of what you need... Think about it. The slop is because the upper and lower at the rear take down pin typically have play at the pin - creating space between the mating suraces that allows the movement - so the proper fix is at the pin with something that pulls the upper down onto the lower, not pushes it away. This can be accomplished by drilling and tapping the rear lug at a 45 degree angle to the lower recievers top side and insalling a small set screw with threadlock agent. (once the propper depth has been set to put downward tension on the upper & takedown pin) The setscrew tip or nose should be rounded to allow the takedown pin to wedge inbetween the screw and the lower without catching on the setscrew. I will post some pics for clarification later this evening. All of my AR15s have this mod to keep things tight and keep myself sane. :)
Wow, that is a lot of work for something that really is inconsequential. But hey, if it makes you happy rock on. I do things that seem silly to others just to make me happy.
devildogljb
05-28-10, 17:07
its normal i wouldnt worry about it seems like every ar i ever had my hands on did the same thing. Even my m16 did.
A few days ago I was examining an M4 belonging to one of the team guys that we work with. He had an "accucrap" in his lower. It was almost split in half. When I showed him he said, "damn that could have come apart in my lower and caused problems". He promptly threw it away.
They don't serve a purpose other than to make people believe that they are solving a problem that doesn't exist.
Trying to mate a stripped upper won't tell you anything unless you put a BCG in it.
The back of the BCG tensions against the buffer and makes the two halves tighten up.
Too often people will come on the boards complaining about receiver fit and they don't even have the buffer system installed. Then you get 20 bad replies.
DaBears_85
05-28-10, 17:29
They don't serve a purpose other than to make people believe that they are solving a problem that doesn't exist.
Exactly, It's business 101. Create a problem then sell the solution. That "twang buster" thing comes to mind as well...
A few days ago I was examining an M4 belonging to one of the team guys that we work with. He had an "accucrap" in his lower. It was almost split in half. When I showed him he said, "damn that could have come apart in my lower and caused problems". He promptly threw it away.
They don't serve a purpose other than to make people believe that they are solving a problem that doesn't exist.
Maybe the actual brand name ones or the orange ones....but you cannot split the black rubber ones.....you cannot even cut through it unless you have industrial type scissors.
http://store.a51tactical.com/images/ugc-1.jpg
A little wiggle is a good thing. Unfortunately I learned this the hard way when I bought my first rifle which used a VLTOR MUR upper receiver.
The fit was extremely tight on both my LMT and Noveske Lowers. It as a huge PITA removing the upper from the lowers with how tight the fit is between them. I have to use a punch when I want to disassemble this rifle.
With looser fitting uppers and lowers it is never a problem taking the rifle apart without any tools.
I am NOT an expert by any stretch but I don't see a benefit in a tight fitting upper and lower receiver when it comes to the AR15 platform.
if the Ar needed a Accu-wedge: ,Stoner would have put one there:p
I would Not worry to much about it.
What Upper and what Lower Are you Using ?
Blankwaffe
05-28-10, 19:13
Stick a loaded mag in the rifle and see how much wobble you have.Even a empty mag tightens up the wobble in my AR's.
If you want to try something to remove a bit of wobble,get a set of the Armalite NM oversized pivot and take down pins and see what that does for you.
Beyond that I'd avoid the accuwedges and the like products.I cut them down and used them for years on my NM and varmint guns without seeing one fail or come apart.But I have seen the wedges flip up out of their seat when the upper was opened and end up in the FCG if your not paying attention.On a target gun its a pain in the ars...has no place at all on a defensive weapon of any sort.
A $10 part from ArmaLite will solve the problem and not cause any new ones that I am aware of:
http://www.armalite.com/ItemForm.aspx?item=ENM001&Category=5e96660f-cc85-4db9-ab9d-8a3c238a7007
If it really, really bothers you you can glass bed between the upper and lower. Then you can't use either the upper or the lower with anything else, but at least you'll have a tight rifle.
Mil spec is absolutely not a science
Huh? I fail to see what is non-scientific about an established set of specifications to include minimum and maximum values, acceptable tolerances, etc.
Engineering definitely falls under what I consider "science."
unlike most people think, its impossible from one batch of ARs to the next to have them machined and finished to the exact same standard everytime
The standards consist of tolerances and rejection thresholds. The "standard" is not that every part will be 100% identical every time, down to the hair.
If it drives you that mad, try a accu wedge....contrary to what many people think, they will work:)
A small sampling of Accu-Wedge threads:
https://www.m4carbine.net/showthread.php?t=32599
https://www.m4carbine.net/showthread.php?p=558222
https://www.m4carbine.net/showthread.php?p=146891
The "many people" who speak poorly of them here tend to be pretty respected/established members.
Your gun though.
What in the world are people recommending?!?! Glass bedding? Larger pins? Accuwedge? No these are all terrible solutions - they do no change the location surfaces where the pin makes contact. 20 minutes with a drill, tap, and a setscrew and you are done... FOREVER fixing the problem at the upper reciever rear takedown lug. Remember, you want the upper to be pulled down tighter and closer to the lower, not have something push the upper further fom the lower or fill in the gap inbetween... I promise I will get pics up soon - just busy working in the garage. Yes I know as the op also stated, the AR functions fine with sloppy fitment, but that doesn't mean I'm going to leave mine as is because someone else said so.
If it bothers you just give your gun a wedgie (http://www.brownells.com/.aspx/pid=16662/Product/AR_15_M16_ACCU_WEDGE).
http://www.brownells.com/userdocs/products/p_993150100_1.jpg
Maybe the actual brand name ones or the orange ones....but you cannot split the black rubber ones.....you cannot even cut through it unless you have industrial type scissors.
http://store.a51tactical.com/images/ugc-1.jpg
what happens when the accuwedge falls apart? it goes into the trigger group.
I was there once, and was made an example of and removed my accuwedge and have not looked back.
As far as the black rubber ones, they will wear out too.
There is a mil-standard for allowable play between the upper and lower. If yours does not exceed this standard, then don't worry about it.
C4
Blankwaffe
05-28-10, 23:05
A $10 part from ArmaLite will solve the problem and not cause any new ones that I am aware of:
http://www.armalite.com/ItemForm.aspx?item=ENM001&Category=5e96660f-cc85-4db9-ab9d-8a3c238a7007
For it to work appropriately you really need to use the Armalite NM pivot and Take down pin as a set.
The Armalite NM pins I have are .250" exactly vs. the .2475" of my standard pins.
Blankwaffe
05-29-10, 00:18
What in the world are people recommending?!?! Glass bedding? Larger pins? Accuwedge? No these are all terrible solutions - they do no change the location surfaces where the pin makes contact. 20 minutes with a drill, tap, and a setscrew and you are done... FOREVER fixing the problem at the upper reciever rear takedown lug. Remember, you want the upper to be pulled down tighter and closer to the lower, not have something push the upper further fom the lower or fill in the gap inbetween... I promise I will get pics up soon - just busy working in the garage. Yes I know as the op also stated, the AR functions fine with sloppy fitment, but that doesn't mean I'm going to leave mine as is because someone else said so.
Installing the NM pivot and take down pins does not make any permanent modification to the weapon,or introduce foreign items within the receivers mechanical internals.The NM pins are also within the acceptable +/- range/specs of the parts involved,so I see them as the least offensive avenue for folks to take if they feel the need to do something.
As far as the pins having no effect mechanically on moving the surfaces or tightening the tolerance gap between the parts,it does.The NM pins being at a true .250" simply take up more room in the pivot and take down holes of the recievers than the standard .2475" +/- pins,which effectively moves the pivot pin and take down holes of the receivers toward a better alignment.
Now the NM pins do nothing for a loose side to side movement at the receivers pivot or take down lug/mating surfaces.So in that regard as long as your receivers will pass the inspection described in the -23&P,your good to go.
I personally have spent way too many years worrying and talking about wobble in the receivers,and trying all the accuwedge,oring and bedding remedies.
I have come to the conclusion its about as silly as worrying about what color furniture I have on my rifle.Its even more stupid for me to continue to discuss it here.
But as far as the recommendations that have been made so far....personally I'd rather tell somebody to use a set of NM oversized pins of the same design as what is used in the weapon,way before Im willing to take the responsibility/liability of recommending or convincing a person to start drilling holes in receivers and making mods that are not easily reversed,or acceptable to most of the manufacturers warranty departments.
longrange18
05-29-10, 04:42
Wow. Awesome guys, I have a lot of information to take in now. I know it's not an issue as far as function is concern it just bugs me. I guess being new to AR's I just feel that the upper and lower should fit snug.
I'm guessing that the only way to ensure a snug fit would be to buy a match lower and upper. Or maybe a billet upper and lower but I don't have the money for billet receivers. Awesome products though. I would love one of the Magpul lowers. :D
Longrange
QuickStrike
05-29-10, 05:01
Then choose another platform. Just how AR's are, and I personally can't stand pins that are so tight you need a punch to get them loose.
Yea, I'd rather have a looser fit than having to use a punch and mallet for field stripping...
As with many things in this world, there's nothing wrong with some jiggle. :o
Paraclete comes
05-29-10, 06:59
As with many things in this world, there's nothing wrong with some jiggle. :o
I like your style, nothing wrong with a bit of jiggle.
OK Gents...
Here is my last input on this topic.
Please do not post "the play is fine" or something along these lines as we all know this. My answer to the op's question is the best method to remove the play if one is inclined to do so. This fix is permanent and never requires messing with it ever again. And the "tightness" is controlled by the user doing the mod based on how far the setcrew is turned before it is thread-locked into place. I never said anything about it requiring a punch and hammer to undo, just that you can remove the play to your liking. Accuwedge / larger pins / bedding are all bad ideas if you actualy care about remedying the cause of the "jiggle" and not band aid fixing around the problem.
If your upper reciever does not have a small 45 degree flat milled into it, you can slowly create a tiny one with a flat file - file only enough material away so you can start your drill bit and control your drilling operation... follow with tap, and finally thread setscrew with a rounded nose. Follow this simple guide and you will remove the slop in your AR15 the correct way. I will post the drill bit, tap, and setscrew dimensions later this evening.
E-man930
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For it to work appropriately you really need to use the Armalite NM pivot and Take down pin as a set.
The Armalite NM pins I have are .250" exactly vs. the .2475" of my standard pins.
Why do you need to use them as a set? Just the pivot pin does the trick. Using the standard take down pin allows easy field stripping without tools.
3CTactical
05-29-10, 13:38
I've got some Sun Devil lowers with the tensioning set screw and after playing around with them a bit I have come to the conclusion that they are totaly useless, thus I removed them from my lowers. I also agree that the Accuwedges are completely useless as well and only a recipe for trouble. As long as everything is in spec, I wouldn't worry about it.
the wiggle jiggle, ..... mine dont wiggle very much, never really give it much thought.
some of the old colts i saw over in iraq, where pretty loose, but they still shot like champs.
peabody
Blankwaffe
05-29-10, 16:39
Why do you need to use them as a set? Just the pivot pin does the trick. Using the standard take down pin allows easy field stripping without tools.
Ive tried using the NM pins individually and found it works best if both the NM pivot and take down pin is used as it gives a slightly better fit to the parts.The Gunsmith at Armalite also recommended that both pins be used as a set.
No other reasons beyond that really.
That said if the pins fit so tight in the receivers that tools are needed for normal disassembly,then I would not use the NM pins in that assembly.
I used national match pins and realized that when I swap out uppers one of them was on the tight side and did not fit so out they came and I started fixing the uppers to fit my lower snug instead of the other way around. Anyone that wants the .250 pins can email me and I will ship them to you on your dime - they are not for me.
3/32 drill bit / 6 - 32 tap & respective set screw available at most local hardaware stores such as Ace.
3/32 drill bit / 6 - 32 tap & respective set screw available at most local hardaware stores such as Ace.
Thanks for the pics and the mod. It looks to work if the jiggle bothers you. I may try it on one of mine.
outrider627
05-31-10, 11:28
I'm able to fit a .009in/.229mm feeler gauge between the upper and lower. Is that normal?
Accuwedge and lower reciever tension screws are the oppsite of what you need... Think about it. The slop is because the upper and lower at the rear take down pin typically have play at the pin - creating space between the mating suraces that allows the movement - so the proper fix is at the pin with something that pulls the upper down onto the lower, not pushes it away. This can be accomplished by drilling and tapping the rear lug at a 45 degree angle to the lower recievers top side and insalling a small set screw with threadlock agent. (once the propper depth has been set to put downward tension on the upper & takedown pin) The setscrew tip or nose should be rounded to allow the takedown pin to wedge inbetween the screw and the lower without catching on the setscrew. I will post some pics for clarification later this evening. All of my AR15s have this mod to keep things tight and keep myself sane. :)
Can you post those pics? I'd really like to see this mod.
The military standard is that a .020 feeler gage should not be able to penetrate in the area of the pivot pin lugs.
...Can you post those pics? I'd really like to see this mod.
Links to picks are in post # 30
shrunk the pics by 50% which already were 50% of native resolution... :D
shrunk the pics by 50% which already were 50% of native resolution... :D
People need to update their old 1024x768 dinosaur monitors and embrace the 1920x1080 widescreen revolution :D
This topic has been discussed enough.
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