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Discussion Starter · #1 ·
Just picked up my XCR. Haven't shot it yet, but hoping to get to that this weekend. While I was working on it this evening, I noticed that the upper and lower receiver are not quite aligned at the rear. The upper protrudes on one side, relative to the lower, and is inset on the other. I thumbed the lock and took a peek, and the blind hole at the back of the lower, where the end of the receiver lock rests, appears to be a bit off-center. Is this normal/correct/ok? Is there a tolerance or spec for the position of this hole?
 

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I've never looked closely at the position of the hole you speak of, but the slight overhang of the upper over the lower on the left rear side is intentional/by design, and is present on every XCR. I believe it is to make sure the rear part of the charging handle has adequate clearance.
 

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Discussion Starter · #3 ·
That's music to my ears, ny. The upper and lower appear to have been shaped to mate flush, which leads one to hypothesize that someone set up their machine wrong when they drilled that hole! :eek:
 

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I just purchased an XCR last week and immediately noticed the receiver misalignment you speak of and was concerned. I am surprised it is intentional. I also noticed the amount of play between the upper and lower receivers. The gun felt loose when I first picked it up. I adjusted the folding stock as the manual suggests and it no longer wobbles but the gun still feels loose with the side to side play between the receivers. You can see daylight between the receivers and I have not noticed this or the looseness with the Ar's I have handled or the Sig 556. I can just slip the cover of my manual between the upper and lower receiver. Is this normal? The receiver lock does seem to be positively engaged.
 

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Some fits are different than others. You should be able to fit a fingernail (unless you have super thick fingernails) in-between the receivers. It is normal, and how the gun is made. Some will have a small gap, but all have a slight gap.
 

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The looseness between the upper and lower receivers is really aggravating me. I would have expected a tight fit. As mentioned in a previous post, you can feel it as soon as you pick up the gun. If I had an AR, I could use an accu-wedge to tighten up the fit. Since there is not an accu-wedge for the XCR, I went to True Value and found some thin sticky back rubber pieces and stuck them to the lower receiver to tighten up the fit between the receivers. The gun now feels rock solid but there is an issue with needing to use a little extra umph to lock the receivers together. That can probably be taken care of by sanding down the thickness of the rubber pieces or finding some thinner ones. Does anybody see an issue with doing this and does anyone else have issues with looseness between the receivers and have come up with a way of taking care of it? I know the pieces may wear and can deteriorate from cleaning solevents but they cost next to nothing and can be replaced easily. I have not shot the rifle with these mods. It will not hurt my feelings if you tell me this is a bad idea. I am trying to attach a couple of pictures but I a keep getting a file is too big message. I shot the pictures again at the 2MP instead of the 10MP setting but keep getting the same message. Maybe I need to lower the JPEG quality setting. I should have never switched from film! Anyway, I will work at it a bit and see if I can get them posted so you can get a better idea of what I am talking about.
Thanks
 

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As far as the tightness of the upper/lower receiver fit,I too don't care for the "looseness".I don't think it affects accuracy,but it still think it should be tighter.It's not a huge issue but to some people it gives the impression of improper fitting or cheapness.It's just gives the AR fanboys one more thing to bitch about.I have thought about making my own shim to take up the slack,but just never got around to it.
 

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Weird my rifle is rather tight.
 

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As far as the tightness of the upper/lower receiver fit,I too don't care for the "looseness".I don't think it affects accuracy,but it still think it should be tighter.It's not a huge issue but to some people it gives the impression of improper fitting or cheapness.It's just gives the AR fanboys one more thing to bitch about.I have thought about making my own shim to take up the slack,but just never got around to it.
Let them bitch. It's just ignorance rearing its ugly head. ;)
 

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Exactly DTOM. Everyone who checks out the XCR likes it but they all have the same comment about the loose feel. Putting those small rubber pieces on the bottom receiver really makes the gun feel much more solid. I don't think the shims should make a difference as long as the receivers still lock together properly.
 

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Those little rubber thingums you're putting between your receivers don't do a damn thing, aside from seperate you from your money. And introduce shit into your rifle that doesn't belong there and will eventually cause trouble. Don't do this. It's a bad idea and utterly, completely without merit of any kind.
 

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Wristlock,
Thanks for the link.

Sloan411,
Thanks for the heads up, I didn't think about the rubber wearing and getting into the rifle. As far as merit, I don't know...
 

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I think that the accuwedge was proven to do nothing for "accuracy" and only makes one feel better about a firearm. I have a couple Sun Devil Lowers that have that adjustment screw built in, nifty little invention.

I honestly don't remember how tight my XCR is but I don't ever remember it being unusually loose.

If yours bothers you throw the rubber in there. It shouldn't hurt anything. Just make sure it doesn't interfere with safety/fire control group manipulation.

Whatever floats your boat. :2cents:
 

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I was thinking more like a shim,not rubber but maybe plastic,so long as it didn't move and there was just enough play to allow the two halves to close without any binding.It would have to be thin yet with a reliable method of attachment.I honestly don't care to Superglue anything to my XCR so thats one reason why I haven't messed with it.I know in my mind it doesn't hurt a damn thing,but it still bugs the shit out of me nonetheless.
I love this rifle,It has so many great things about it and so few negatives,not to mention tremendous value in a category that up until recently had no real equals,and still none close to it's price or availability(please spare me the gas piston AR bit,I ain't buying it) So I can live with this one little preturbance,I do feel however that it can and will(however unfairly or ignorantly) affect peoples opinion of this awesome platform.My point is I would educate those who do not know,but they don't always take your word for it(those who know it all seldom do) and second those who we aren't around to educate are brainwashed that the fit is imperative to superb accuracy.I wish very much for this platform to succeed in a big way,It's good and more people need to know it,that's one reason why it irritates me,I hate to see anything detract from that.
 

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I had friends who used these things on ARs and, frankly, it didn't seem to do anything at all--other than cost about $7 that could have been better spent on beer or pizza.

Most of my animosity towards little plastic/rubber whatsits comes from experience with the so-called recoil buffers on 1911s. These are pure, unadultered shit. No ifs ands or buts. These will cause malfunctions sooner or later and it's usually sooner. Waste of time and money and reduces confidence in the gun. Like 1911s don't have enough problems to overcome with all the variations (mostly bad) out there.

I'd stay away. ARs shoot very well generally, and the XCR is a good shooter. I don't think they need the reciever fit tightened at all. Rattling guns never bothered me particularly.
 

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I can really only speak to mine and one other that I have handled, but they are about equally tight as the upper and lower on a regular AR... I'm not any more likely to stick rubber between the XCR receivers than I am to stick an Accuwedge in my ARs.

If "AR fanboys" want to bitch about something regarding the XCR, it can't be this, since their rifles exhibit the exact same characteristic.
 

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Just picked up my XCR. Haven't shot it yet, but hoping to get to that this weekend. While I was working on it this evening, I noticed that the upper and lower receiver are not quite aligned at the rear. The upper protrudes on one side, relative to the lower, and is inset on the other. I thumbed the lock and took a peek, and the blind hole at the back of the lower, where the end of the receiver lock rests, appears to be a bit off-center. Is this normal/correct/ok? Is there a tolerance or spec for the position of this hole?
Normal. Here is an old thread that covered this topic. The slight ledge on the left side is part of the charging handle clearance

http://xcrforum.com/index.php/topic,103.msg792.html#msg792

To reduce play between the upper and lower, add a thin strip of skate tape, or even duct tape to outer ledge of the lower, just above the safety selector on the right side. It must be thin in width and height. The goal is reduce play not prevent the upper from locking closed. When your gun is assembled, it will pancake the tape, so there is zero chance if having it slide into the action, even if wet and the adhesive fails.

This is my version of an accuwedge.
 

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The looseness between the upper and lower receivers is really aggravating me. I would have expected a tight fit. As mentioned in a previous post, you can feel it as soon as you pick up the gun. If I had an AR, I could use an accu-wedge to tighten up the fit. Since there is not an accu-wedge for the XCR, I went to True Value and found some thin sticky back rubber pieces and stuck them to the lower receiver to tighten up the fit between the receivers. The gun now feels rock solid but there is an issue with needing to use a little extra umph to lock the receivers together. That can probably be taken care of by sanding down the thickness of the rubber pieces or finding some thinner ones. Does anybody see an issue with doing this and does anyone else have issues with looseness between the receivers and have come up with a way of taking care of it? I know the pieces may wear and can deteriorate from cleaning solevents but they cost next to nothing and can be replaced easily. I have not shot the rifle with these mods. It will not hurt my feelings if you tell me this is a bad idea. I am trying to attach a couple of pictures but I a keep getting a file is too big message. I shot the pictures again at the 2MP instead of the 10MP setting but keep getting the same message. Maybe I need to lower the JPEG quality setting. I should have never switched from film! Anyway, I will work at it a bit and see if I can get them posted so you can get a better idea of what I am talking about.
Thanks
I don't have mine yet---but I have to say it's a psychological thing. I've qualified high expert with some sad old M16 A2s on the USMC range which I thought would have been affected by a loose upper receiver (which you could see hints of light through). At 500 yards, proper fundamentals were all that were necessary-good sight alignment and sight picture paid off every time. Personally-I'd be real scared to do damage to the rifle by changing a fit or measurement from the manufacturer, even if only with rubber. But I'm not a armorer soooooooo....
 
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