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AR flattop upper

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May 16, 2025, 04:22 PM
Citadel
AR flattop upper
Buddy has a A2 HBAR, would like to make it into a flat top. Any recommendations?
May 16, 2025, 04:49 PM
parabellum
A Colt upper? I wouldn't change a thing, but you would have to separate the barrel from the upper receiver, then remount the barrel and gas tube on a new flat top receiver. Probably more trouble than it's worth.
May 16, 2025, 08:45 PM
ArtieS
Keep that upper the way it is. Just buy a new upper.



"I vowed to myself to fight against evil more completely and more wholeheartedly than I ever did before. . . . That’s the only way to pay back part of that vast debt, to live up to and try to fulfill that tremendous obligation."

Alfred Hornik, Sunday, December 2, 1945 to his family, on his continuing duty to others for surviving WW II.
May 16, 2025, 09:32 PM
lyman
quote:
Originally posted by ArtieS:
Keep that upper the way it is. Just buy a new upper.


this is the way



https://chandlersfirearms.com/chesterfield-armament/
May 16, 2025, 09:33 PM
RogueJSK
Yep. Get a new upper assembly.

If he doesn't want the A2 HBAR upper at all any more, he could sell it to cover some/all of the cost of the new upper.
May 16, 2025, 09:49 PM
KMitch200
Your buddy can get an AR Stoner upper for for $250 from Midway.
Keep the original upper as is.

LINK
1 in 8 twist, 223 Wylde chamber, A2 flash hider, complete upper.


--------
After the game, the King and the pawn go into the same box.
May 17, 2025, 07:14 AM
Mars_Attacks
Yeah, just buy a complete upper.

I only do swaps the other way around.


____________________________

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May 18, 2025, 01:03 PM
Gas Motorhead
This appears to non Colt people easier than it looks. Colt in my memory only offered a few HBAR true `1/7 uppers about 20+ years ago. The issue you have is you can find HBAR A2 rifles and current uppers. The current uppers are cut with M4 feed ramps where the barrels are not. Non compatible!! In my opinion this is easier with aftermarket parts (non Colt). If not you will need to find an older flat top upper without M4 feed ramps from a older sporter blue label gun.
May 18, 2025, 01:40 PM
Mars_Attacks
Just buy a non M4 rifle receiver. They are universal donors.


____________________________

Eeewwww, don't touch it!
Here, poke at it with this stick.
May 21, 2025, 05:53 PM
Expert308
If you do decide to put a different (flat top) upper on the rifle, check the takedown pin first. My Colt A2 HBAR, which I no longer own, had the oversized takedown pin which is bigger in diameter than the "standard" takedown push-pin. You used to be able to buy an adapter for a few bucks that would let you mate a small-pin upper with the Colt big-pin lower, but I don't know if those are still available.