How to fix wobble between upper and lower on AR?
- Thread starter hobgob
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Don't have to, don't need to. Function is not affected. But, if you insists, then try the Accuwedge.
BADUNAME37
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Bushmaster has a wedge-bolt type arrangement that increases diameter as it is being tightened. This replaces the large rear pin, but could also replace the front pin on certain models. The bolt is about $45.
The one problem with it is it takes about fifteen extra minutes to remove the rear pin, as now you need to unscrew the wedge using an allen wrench. If you take a shot and something happens where you need to drive out that rear pin to separate the upper from the lower, possibly to remove a primer that fell out, or whatever, you are not going to be taking any shots while you are playing with this wedge-bolt!
I also have the accu-wedge. The wedge-bolt and accuwedge did not seem to help at all with accurace, so they sit in my miscellaneous items box like I should have just not bought them.:banghead:
The one problem with it is it takes about fifteen extra minutes to remove the rear pin, as now you need to unscrew the wedge using an allen wrench. If you take a shot and something happens where you need to drive out that rear pin to separate the upper from the lower, possibly to remove a primer that fell out, or whatever, you are not going to be taking any shots while you are playing with this wedge-bolt!
I also have the accu-wedge. The wedge-bolt and accuwedge did not seem to help at all with accurace, so they sit in my miscellaneous items box like I should have just not bought them.:banghead:
The need to fix the wobble is aesthetic. If this is a plinking or hunting gun, go ahead and "fix it" if the wobble bothers you. If your rifle is a self defense tool, DO NOT put a piece of foreign plastic into your lower receiver. There is a chance the wedge can break, and pieces can end up places they don't belong, causing malfunctions.
Creature
Member
Agree and agree. Waste of money.
kwelz
Member
It is worth repeating that you should NOT use the accuwedge or any other aftermarket product that is designed to tighten the upper and lower. They introduce a host of problems and fix nothing. If the wobble i so bad it effects function then there are bigger issues at play and if it is not then leave it alone.
451 Detonics
Member
I have been using Accuwedges in all of my ARs for well over 20 years and have never had a problem. These include not only standard ARs but my 11 inch and 300 Whisper.
What problems are they supposed to cause?
What problems are they supposed to cause?
Well, they spend money on something that won't do anything to actually increase accuracy. They raise false hopes, and obscure how the weapon actually functions - which has very little to do with relic bolt gun designs with the action mounted in a stock.
If it's that much of a bother, a 29c o ring on the forward lug does ok. Otherwise, the fit between upper and lower has no affect on barrel harmonics, sight picture, or accuracy. Most AR's are 2MOA chrome barreled plinkers, good enough for combat and hunting, as they shoot about an 8" spread at 400 yards. That's targeting an 18" kill zone on a live target.
Accuwedges are just the tip of the iceberg in the shooting publics misconceptions about accuracy, and a good example of how much is done from a dollar per unit benefit view.
If you don't have a 1/4 MOA written guarantee barrel, don't even start with "accuracy" excuses to purchase stuff. Tune handloaded ammo first - white box fodder won't ever achieve any notable accuracy. Get a decent optic and practice, that will tighten groups up 50% on the average. With ammo and optic, you will be shooting much closer to the natural dispersion of the barrel. Tune it next, get the harmonics to the point the muzzle doesn't vibrate when the bullet exits. Eliminate moving the POI because of shooter inconsistency, free float the barrel. Last, use a quality trigger.
In that order - barrel, ammo, optic, furniture, trigger, you get an accurate AR. If working at it backwards was worth it, a sniper stock, free float, and $250 trigger would make a $599 bargain gun shoot like a DMR. And we all know, it won't. Too many still delude themselves, drink the koolaid, and shell out $100's on accessories for a 2MOA barreled gun. It's mostly bling. Might as well get Airsoft.
That's what's wrong with "fixing" the rattle, it does no good, and perpetuates a lot of misinformation.
If it's that much of a bother, a 29c o ring on the forward lug does ok. Otherwise, the fit between upper and lower has no affect on barrel harmonics, sight picture, or accuracy. Most AR's are 2MOA chrome barreled plinkers, good enough for combat and hunting, as they shoot about an 8" spread at 400 yards. That's targeting an 18" kill zone on a live target.
Accuwedges are just the tip of the iceberg in the shooting publics misconceptions about accuracy, and a good example of how much is done from a dollar per unit benefit view.
If you don't have a 1/4 MOA written guarantee barrel, don't even start with "accuracy" excuses to purchase stuff. Tune handloaded ammo first - white box fodder won't ever achieve any notable accuracy. Get a decent optic and practice, that will tighten groups up 50% on the average. With ammo and optic, you will be shooting much closer to the natural dispersion of the barrel. Tune it next, get the harmonics to the point the muzzle doesn't vibrate when the bullet exits. Eliminate moving the POI because of shooter inconsistency, free float the barrel. Last, use a quality trigger.
In that order - barrel, ammo, optic, furniture, trigger, you get an accurate AR. If working at it backwards was worth it, a sniper stock, free float, and $250 trigger would make a $599 bargain gun shoot like a DMR. And we all know, it won't. Too many still delude themselves, drink the koolaid, and shell out $100's on accessories for a 2MOA barreled gun. It's mostly bling. Might as well get Airsoft.
That's what's wrong with "fixing" the rattle, it does no good, and perpetuates a lot of misinformation.
The most important function of the accuwedge is to prevent you from being distracted by the sloppiness that is bothering you. A good percentage of what separates a decent shooter from a champion is mental- and if this rattle is going to distract you or create doubt then you need to fix it. But just realize it is fixing YOU not the rifle.
It is an extra piece of plastic that, if damaged, can get into places where it doesn't belong. It isn't the causation, but rather the effect of having i t in place. There is no reason to use one, wobble won't affect reliability.
Mike128
Member
Wobble won't affect anything with the rifle. But I can see how it would annoy someone. Another easy fix is an O-ring around the studs of the upper. (I don't know what it is called.) The area of the upper that extends into the lower and the retaining pin goes through.
Accuwedge also works and I haven't really heard of that causing any problems. The O ring basically acts as an accuwedge.
Accuwedge also works and I haven't really heard of that causing any problems. The O ring basically acts as an accuwedge.
451 Detonics
Member
Well there really isn't a way for it to be damaged while firing and mine have been in guns for many thousands of round without issue. They are not hard plastic that can chip but a softer material that is completely protected when the gun is assembled.
Wobble won't affect function but for precision shooting it can affect cheek weld and eye relief...it may not help most people but then it can't hurt either and may make the difference between a 10 and a 10X.
AK103K
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I have a Bushmaster that has terrible wobble between the upper and lower. So much so, its very distracting while shooting.
I tried an Accuwedge, but it was actually to small, and I ended up making my own from a drafting eraser.
That still didnt remove all the wobble, so I went with the "O" ring on the front post too, and now shes just like a German virgin. Gut en tight.
Ive never had any problems with the eraser coming apart or even looking like it would anytime soon. I still check it each time the gun gets cleaned though, just like I check everything else.
Now my Bushmaster has never been one of my more accurate AR's, but having the wobble gone, certainly hasnt hurt. At least you can shoot the gun without distraction, which is a good thing.
I tried an Accuwedge, but it was actually to small, and I ended up making my own from a drafting eraser.
That still didnt remove all the wobble, so I went with the "O" ring on the front post too, and now shes just like a German virgin. Gut en tight.
Ive never had any problems with the eraser coming apart or even looking like it would anytime soon. I still check it each time the gun gets cleaned though, just like I check everything else.
Now my Bushmaster has never been one of my more accurate AR's, but having the wobble gone, certainly hasnt hurt. At least you can shoot the gun without distraction, which is a good thing.
MattTheHat
Member
You could also drill and tap into the lower receiver behind the grip mount and install a nylon-tipped set screw which can be snugged up. My Mega Machine billet lower has that arrangement and I've seen several others that do as well.
I'm personally irritated by a rattle-trap upper/lower fit, but as others have indicated it's certainly not a huge deal.
-Matt
I'm personally irritated by a rattle-trap upper/lower fit, but as others have indicated it's certainly not a huge deal.
-Matt
The O ring seems like a better idea. It stays out of the receiver and is much cheaper. I agree with the other posts that if the wobble does not affect accuracy, then why fix it? I have a upper and lower DPMS M4 and the wobble is actually annoying so I too want to fix it.
JustinJ
Member
The accu wedge is rubber, not plastic, and there is no way it will come loose and disrupt function of the gun if properly installed.
A key to accuracy is consistency so a loose lower and upper could in theory alter the way rounds are fed though it will be slight. For precision shooting i believe an accuwedge ceratinly would not hurt but for most standar ARs any improvement would be negiligible but they are cheap and easy to install so i say slap one in there. The main benefit I see though is they will prevent the fit between upper and lower from getting even looser over time.
A key to accuracy is consistency so a loose lower and upper could in theory alter the way rounds are fed though it will be slight. For precision shooting i believe an accuwedge ceratinly would not hurt but for most standar ARs any improvement would be negiligible but they are cheap and easy to install so i say slap one in there. The main benefit I see though is they will prevent the fit between upper and lower from getting even looser over time.
How would the fit become more loose over time? I would think that might denote something is wearing where it shouldn't be, and would be a much bigger problem than a little "wobble".
kwelz
Member
They can and have come apart, I have seen it first hand. It isn't that they come loose it is that they fall apart and you have pieces of plastic/rubber/whatever flaoting around in your lower.
They Key to accuracy is trigger control. If your sights are on the target and you know how to work the trigger then the round is going to go where you tell it. The fit between the upper and lower will not have any impact on this.
If you don't mind taking a chance on screwing up your gun sure.
Actually this is the exact opposite of true. One other thing they do is put unnatural pressure on the rear takedown pin and holes. As the gun is fired it will vibrate. This can cause wear. And if the pressure is consistent in pushing the pin against a certain spot then the steel takedown pin can wear the hole in the aluminum into an Oval shape.
If it bugs you that much, then whatever, throw an O-ring on the lug. Just know that you are not improving the rifle itself in any way. They are supposed to have a bit of play, it's normal. All the shooting goes on in the upper receiver, the lower is just user interface.
sappnasty
member
Accu-wedge - I have one in my Spike's rifle and there is ZERO play. You can get em' online for between $5-$7.
JustinJ
Member
Sorry but I have a hard time believing an accuwedge would come apart if properly installed given the way they are held when installed and that there are no moving parts contacting them.
"They Key to accuracy is trigger control. If your sights are on the target and you know how to work the trigger then the round is going to go where you tell it. The fit between the upper and lower will not have any impact on this."
If trigger control were the only key to accuracy all rifles would contain the same accuracy potential and AKs would be just as accurate as high end bolt action sniper rifles. There are a many factors that affect accuracy but for the most part they are about providing mechanical consistency from one shot to the next. The way a bullet goes into the chamber is one of the factors as it affects how it will seat and that is where upper/lower looseness comes into play.
"One other thing they do is put unnatural pressure on the rear takedown pin and holes. As the gun is fired it will vibrate. This can cause wear. And if the pressure is consistent in pushing the pin against a certain spot then the steel takedown pin can wear the hole in the aluminum into an Oval shape."
By installing an accuwedge you are minmizing the amount of vibration that occurs at the pin. This is obvious by observing the amount of movement before and after installing an accuwedge. The more two metal parts move around the more and faster they wear. An accuwedge minimizes movement. The same principle applies to bearings, motors, pistons, whatever. If they are loose they wear rapidly. As they become looser the wear is accelerated.
"They Key to accuracy is trigger control. If your sights are on the target and you know how to work the trigger then the round is going to go where you tell it. The fit between the upper and lower will not have any impact on this."
If trigger control were the only key to accuracy all rifles would contain the same accuracy potential and AKs would be just as accurate as high end bolt action sniper rifles. There are a many factors that affect accuracy but for the most part they are about providing mechanical consistency from one shot to the next. The way a bullet goes into the chamber is one of the factors as it affects how it will seat and that is where upper/lower looseness comes into play.
"One other thing they do is put unnatural pressure on the rear takedown pin and holes. As the gun is fired it will vibrate. This can cause wear. And if the pressure is consistent in pushing the pin against a certain spot then the steel takedown pin can wear the hole in the aluminum into an Oval shape."
By installing an accuwedge you are minmizing the amount of vibration that occurs at the pin. This is obvious by observing the amount of movement before and after installing an accuwedge. The more two metal parts move around the more and faster they wear. An accuwedge minimizes movement. The same principle applies to bearings, motors, pistons, whatever. If they are loose they wear rapidly. As they become looser the wear is accelerated.
The shooters I trust all say stay away from the Accuwedge, so away I stay.
The wobble isnt effecting function that I know of. I am still in the process of building this rifle. Yet since it is intended for hunting, I just want to make sure I can get the best shot every time. still need an optic and to sight it in to test accuracy. Honestly after all the negative comments I think I have made up my mind and untill I see a definitive effect on function or accuracy I will just deal with the wobble.
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