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Posted: 7/2/2026 2:47:13 PM EDT
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I bought a colt upper. 20" hbar marked "CMP 556 NATO 1/9 HBAR". Not sure if it's original as factory assembled but here's the details : 20" non threaded, no bayonet lug F marked fsb C AF marked flat top C stamped bolt carrier MPC marked bolt National match style free float tube under the handguards The barrel has two ridges on the exterior about halfway from the receiver to gas block. I haven't seen that profile before. Any help identifying why it has the ridges would be appreciated. Thanks |
| Look under the handguards for a mm/yr date on barrel. Either behind gas block or in front of chamber/barrel nut. Is the upper pivot pin standard or large diameter? |
De Oppresso Liber
Iraq: 91,03,04,05,06,08,09,15,16,22-26'
Afghanistan: 09,10,11,14,17,-21'
Iraq: 91,03,04,05,06,08,09,15,16,22-26'
Afghanistan: 09,10,11,14,17,-21'
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