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Posted: 4/28/2006 3:35:10 AM EDT
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I have a Colt A2 HBAR 20" Target or Match. I want to convert it to a flat top for easier scope mounting. Brownells has an upper that says, Colt Receiver, Upper, Flat Top, 16" Carbine. http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=4798&title=RECEIVER%2c+UPPER%2c+FLAT+TOP%2c+16%22+CARBINE I think its an M4 upper. My question is......Will this replace my A2 upper or are there differences between the 16" Carbine and the A2 HBAR. I've read various threads saying there are differences, and some threads saying it will fit no problem! Any insight will be greatly appreciated! hinking.gif Steve |
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check Specialized Armament...they sell Colt parts but they are very expensive. like eklikwhoa said, get a CMT upper: it the exact same upper but it's cheaper. it just miss the "C" but it's the same. |
The Colt flat top upper that you found is the wrong upper for your rifle, that upper is for carbines only which have carbine M4 extended feedramps, it will not work with your standard rifle feedramps on your barrel extension. The correct flat top upper is this Part Number 160-302-050 Receiver, Upper which fits the AR-15 Match Target Competition HBAR which is the flat top HBAR rifle model. You will also need to get a taller front sight because the flat top upper receivers are 0.040" higher than the A2 upper receivers, but if you won't be using any back up iron sights at all you don't have to buy it. Good luck on your project.  ETA: These new Colt upper receivers are all small hole pivot pin 0.250" DIA, if you have a large hole pivot pin of 0.312" DIA lower receiver you also need to buy a pivot pin conversion (small hole upper to large hole lower). |
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The "M4" uppers have feed ramps cut into them, and if you do not use a barrel with properly cut feed ramps in the barrel extension to match the receiver cuts you are seriously jeopardizing reliability. On the other hand, a barrel wtih feed ramps will work fine in an upper without ramp cuts. Del-Ton has CMMG uppers for $95. I have used them and they are great uppers. It's up to you. It's your wallet. They are available with or without feed ramps btw... YMMV |
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Thanks Alfa-Romeo3, I also want to thank the other people that commented. Since its a Colt, I want to keep it a Colt. You gave me exactly what I needed! Now I just need to get the proper tools to do the conversion. The pivot pin is the 0.250 pin! Thanks again! Steve |
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