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Posted: 6/12/2013 12:05:19 PM EDT
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Hi all,
I have a Chippa M4 upper Assy. It is great in detail including the upper receiver. The receiver itself is a Poly material like to Omni and other poly lowers. The upper receiver ( just the upper, nt the entire barrel / upper assy) is identical to a aluminum AR upper, i.e. all holes for the gas tube, forward assist is correct dimentions, dust cover interchanges and functions, and an actual AR M45 5.56 barrel will fit on as well as the delta ring and snap ring and spring.... My question is, does anyone think that this upper would work on an actual 5.56 barrel? With a rotary bolt and ease of headspace on these black beauties, I would think so. all of the pressure is really forced through the gas system. only the bolt will slide back into the buffer... What do you think, anyone have any experience using a polly upper? |
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Oly and others have used polymer uppers for years without any problems. I have built up several complete poly guns (uppers and lowers), and ran them for years without any problems. All the upper does is provide the path for the BCG to recoil back into the buttstock. All the pressure and stress of firing takes place in the barrel extension and chamber of the rifle barrel. Some people hate polymer anything on an AR.
Here is one I built that weighs just over 5 pounds and I am selling on Gunbroker to fund another AR project. http://www.gunbroker.com/Auction/ViewItem.aspx?Item=347333588 |
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I have always wondered why those poly model 85's have stayed in place, poly frame, steel barrel and Cyl, ,38 spec packs a punch. I carry a Ruger LCP .380 poly.
All the upper does is house a path for the Bolt CG, all the pressure is taken by the gas system and the chamber, and of course the recoil spring. |
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Quoted: I have always wondered why those poly model 85's have stayed in place, poly frame, steel barrel and Cyl, ,38 spec packs a punch. I carry a Ruger LCP .380 poly. so your comparing a gun designed with poly as a materiel, vs a material being force into a design. Think about it for a sec and realize the folly of it. All the upper does is house a path for the Bolt CG, all the pressure is taken by the gas system and the chamber, and of course the recoil spring. It does just a wee bit more, like hold the barrel in place, take all the strain from the front handguard/forearm as well. If anyone thinks that poly can be substituted for aluminum with the same dimensions and still be okay, is missing a basic engineering class or 2, OP dont use it for 223, maybe a 22lr "might" be okay, but anything with chiappawa on it should be thrown away just on principle. |
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Quoted: Oly and others have used polymer uppers for years without any problems. I have built up several complete poly guns (uppers and lowers), and ran them for years without any problems. All the upper does is provide the path for the BCG to recoil back into the buttstock. All the pressure and stress of firing takes place in the barrel extension and chamber of the rifle barrel. Some people hate polymer anything on an AR. It funny all the new guys have run them for "years" yet anyone with any time on arf will tel you to run when you see poly, the exception being cavarms. Why do you think that is??? Exceptions do not make rules. Also oly and others have had a shitload of problems, do a search.  http://www.ar15.com/forums/t_1_5/1476166_Poly_lowers_.html&light=poly some uppers in there as well |
| Chippa uses a ciener style bolt, I think the upper in question will accept 5.56 related parts. Bushmaster Carbon15 uppers generally have held up well, some brands of poly lowers have not. I would be hesitant to recommend it just because manufacturer doesn't and there is always a risk of injury. |
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Quoted:
I bought a complete Chiappa upper off of the EE. As soon as I got it I took it apart and used an aluminum upper reciever. It shoots really well for the money with a Bushnell TRS sight on top.  So your Chiappa .22 bcg fit the mil spec upper receiver? Dave N |
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Quoted: Chippa uses a ciener style bolt, I think the upper in question will accept 5.56 related parts. Bushmaster Carbon15 uppers generally have held up well, some brands of poly lowers have not. I would be hesitant to recommend it just because manufacturer doesn't and there is always a risk of injury. Carbon 15 uppers have not held up well |
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Quoted: Quoted: Chippa uses a ciener style bolt, I think the upper in question will accept 5.56 related parts. Bushmaster Carbon15 uppers generally have held up well, some brands of poly lowers have not. I would be hesitant to recommend it just because manufacturer doesn't and there is always a risk of injury. Carbon 15 uppers have not held up well Well I read on the internet!  |
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