Removing play between lower/upper

welder179

welder179

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I've got a S&W M&P 15 and there's quite a bit of play between the upper/lower. Is there a MacGyver way to remove or reduce this?
 
greywolf67nt said:
i have 2 friends and now you that have had this issue. I guess QC at S&W isn't what it used to be.
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Didn't expect much for a $600 AR, but now that I've free floated the handguard and put a match rifle length barrel on it I feel it's time to address some of the finer points.
 
welder179 said:
Didn't expect much for a $600 AR, but now that I've free floated the handguard and put a match rifle length barrel on it I feel it's time to address some of the finer points.
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Has zero effects on the gun. It doesn't matter.

Accu wedge if you want to waste your time.
 
r34skyline said:
Has zero effects on the gun. It doesn't matter.

Accu wedge if you want to waste your time.
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Please explain how it has no effect

Seeing as the movement between the stabilized part of the gun (lower) and the barrel under recoil impulse changes the point of aim and therefor the point of impact.
 
Daver_II said:
Please explain how it has no effect

Seeing as the movement between the stabilized part of the gun (lower) and the barrel under recoil impulse changes the point of aim and therefor the point of impact.
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Everything is in the upper that effects accuracy after the trigger is pulled. The play won’t matter unless you are shooting with the upper unsupported.
 
When you look at slow-mo vids, the recoil seems to happen well after the bullet has left the barrel. But I've been wrong before.

OP, if you want to shim the upper/lower to remove play, cut strips of electrical tape the width of the receiver walls and stick 'em on the upper or lower receiver walls just around the takedown pin area. That'll snug things up. Just wipe down the area with some rubbing alcohol to remove any oils.
 
You could find an accu wedge anywhere that sells ARs. They're only around $4 which is better than trying to micky mouse something together. I got TNAs to throw in a bunch with one of my orders just in case I needed them but I haven't yet for any of my builds (knock on wood).
 
Daver_II said:
Please explain how it has no effect

Seeing as the movement between the stabilized part of the gun (lower) and the barrel under recoil impulse changes the point of aim and therefor the point of impact.
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Because once you load the bipod you take the slop out of the upper. Same goes for any degree of support. And the action doesn't unlock till the bullet has left the barrel. All the working components that affect the guns accuracy are housed in the upper assembly.

This stupid myth needs to die already.

Tell you what. Do an accuwedge shim whatever bs soution you have to the "slop" and show me any actual measured difference in accuracy.
 
r34skyline said:
Because once you load the bipod you take the slop out of the upper. Same goes for any degree of support. And the action doesn't unlock till the bullet has left the barrel. All the working components that affect the guns accuracy are housed in the upper assembly.

This stupid myth needs to die already.

Tell you what. Do an accuwedge shim whatever bs soution you have to the "slop" and show me any actual measured difference in accuracy.
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Exactly,
If the little bit of slop annoys you then waste money and time trying to remove it but the rifle won't be any more accurate afterwards.

It has nothing to do with quality control or it being a cheap AR, it's the way the rifles were designed and almost all AR have some wiggle. Even my PWS that was over $2000 had some play between the upper and lower.
By the way, that PWS would shoot sub moa with it's factory 12 inch barrel and non free floated factory quadrail. So just like the upper/lower slop myth the free floated barrel thing is typically misinterpreted as to it's true advantage.
The free floating of the barrel may improve accuracy a tiny bit but the accuracy improvement mostly comes from installing a quality barrel. Free floating an AR or other semi auto is actually mostly impossible since the gas system is always dangling off the barrel but we're freeing it up as much as possible. Where most of the accuracy improvement comes from "free floating" is the consistency increase by taking away the forces of a bipod or sandbag, or your arm from the barrel.
Do we also want to talk about the other stupid myths out there like how people think long barrels are more accurate than short barrels?
 
cr5 said:
Exactly,
If the little bit of slop annoys you then waste money and time trying to remove it but the rifle won't be any more accurate afterwards.

It has nothing to do with quality control or it being a cheap AR, it's the way the rifles were designed and almost all AR have some wiggle. Even my PWS that was over $2000 had some play between the upper and lower.
By the way, that PWS would shoot sub moa with it's factory 12 inch barrel and non free floated factory quadrail. So just like the upper/lower slop myth the free floated barrel thing is typically misinterpreted as to it's true advantage.
The free floating of the barrel may improve accuracy a tiny bit but the accuracy improvement mostly comes from installing a quality barrel. Free floating an AR or other semi auto is actually mostly impossible since the gas system is always dangling off the barrel but we're freeing it up as much as possible. Where most of the accuracy improvement comes from "free floating" is the consistency increase by taking away the forces of a bipod or sandbag, or your arm from the barrel.
Do we also want to talk about the other stupid myths out there like how people think long barrels are more accurate than short barrels?
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Wow, such a heated response. Read my post, I never said I wanted to do it to increase accuracy, I know that's not the case. I just wanted to get rid of the wiggle is all since feeling it move bugs me a bit so if there's a simple super cheap way to remove it in happy. As for barrel length yes you are right a longer isn't more accurate I have read all those studies on that point. but I can get more velocity and a better balancing rifle which suits me well.
 
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Got Juice? said:
foam earplug can work as well.
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What? Do you wear them so the rattling between the parts isn't as noticeable? Winky face ;)

Even the military supply Accuwedges for the C7s. It was part of one rebuild sequence. I remember the one I saw was black, and that caught my eye because all the others I'd seen or owned were red.
 
r34skyline said:
Because once you load the bipod you take the slop out of the upper. Same goes for any degree of support. And the action doesn't unlock till the bullet has left the barrel. All the working components that affect the guns accuracy are housed in the upper assembly.

This stupid myth needs to die already.

Tell you what. Do an accuwedge shim whatever bs soution you have to the "slop" and show me any actual measured difference in accuracy.
Click to expand...

Just curious, but then if you were rested on the lower or magazine, the upper would have play still no? With say, a mag well grip?
 
It's a myth because Mr. Stoner discovered this special way of making a barrel and bolt out of even more parts even less rigid than a typical cheap bolt gun, but changing the properties to cause this combination to effect barrel harmonics less will not have any effect...

I've challenged people to produce a peer reviewed study to back up the "fact" that Eugene's design somehow trumps physics. Still waiting...
 
CR5;

Perhaps your definition of accuracy is different than mine?

My definition revolves around how accurately I can shoot the gun.

And I can shoot the gun more accurately when the gun doesn't wobble.
 
I'm new to AR's but I keep seeing that a lot of them have this play and that it's normal. I also see that $600 is a "cheap" gun, but...

Anyway, I bought a $600 DPMS and there's ZERO play. Do they develop this play over time?
 
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