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Posted: 4/6/2009 6:35:49 AM EDT
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Hey guys i'm looking to build an AR and I have a few questions maybe you can help me with.
I'm going to buy an upper and a barrel seperate. Do I need M4 ramps on the upper or not? What if my barrel has an extenstion? Chrome lined or no chrome lined barrel Mil-spec buffer tube or commerical buffer tube? What the difference? I think thats it for now. Thanks guys |
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Quoted:
Hey guys i'm looking to build an AR and I have a few questions maybe you can help me with. I'm going to buy an upper and a barrel seperate. Do I need M4 ramps on the upper or not? It depends on whether or not the extension has M4 cuts on it. If the extension has the cuts, then the receiver should have them as well. If it doesn't, then the receiver shouldn't have them. What if my barrel has an extenstion? Not sure what you're asking. The barrel will need an extension to be installed correctly on the rifle. Chrome lined or no chrome lined barrel This is personal preference, but the general consensus is that chrome lined is more durable for a slight reduction in accuracy. I'd get chrome lined if it were me. Mil-spec buffer tube or commerical buffer tube? What the difference? Which ever you like. The only difference is the outer diameter of the buffer tube. The threaded portion is the same size and will fit any standard lower receiver. If you buy the stock as a complete set, it won't matter. If you buy the buffer tube and stock body separately it will matter. The mil spec tube has a slightly smaller outer diameter. If you install a commercial stock body, it will not fit snugly. You also won't be able to install a mil stock body on a commercial tube since the commercial tube has a larger outer diameter than the mil spec one. |
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The reason why i'm asking is I posted this on another topic.
Quoted:
Will these uppers work with bushmaster barrels? Yes, they will. I think Bushmaster barrel have standard barrel extentions (at least the last ones I have seen), so the regular flat top would be the one you want to use. Also I have a rock river arms 6 pos. stock and i need to replace the buffer tube. I bought a mil-spec one from someone here on the board, so I want to make sure it fits. |
Barrel Extensions are an integral part of the barrel in the AR design, don't let the name throw you, it is NOT some sort of "extension" for special circumstances. AR's deviate from typical rifle design. I'm going to guess the idea was to make the parts more modular and easier to assemble, replace parts. Instead of screwing a barrel into a receiver and adjusting head space. They screw a barrel extension on to the barrel and the chamber is reamed for the proper head space from the barrel extension. The bolt locks into the barrel extension, so as long as the bolt is within spec, the head space should be in spec. That's why the previous poster warned you about getting a barrel without an extension, I guess some company dumped a bunch of salvage barrels that had the extensions removed and people bought them and started to post how they can install a new extension, only to find out it can't be done. The extension is installed before the barrel is finished, if you take it off and install another extension, things won't line up, and specs will be off. |
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