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5.56 Nato

5.56 NATO is a rimless bottlenecked intermediate cartridge developed in the late 1970s in Belgium by FN Herstal. It was standardized as the second standard service rifle cartridge for NATO forces as well as many non-NATO countries.

Is 5.56 NATO more powerful than 223? The 5.56 NATO has a higher pressure than the 223 round and is one of the two major differences. The 5.56 NATO pressure is about 58,000 psi and the 223 round is approximately 55,000 psi.

Why does the military use 556 and not 223? Differences between the two are small but can have a large impact on performance, safety and weapon function. The first difference is the higher pressure level of the 5.56 NATO cartridge which runs at approximately 58,000 psi. A 223 Remington is loaded to approximately 55,000 psi.

Our 5.56 NATO uppers all come with a 100% satisfaction guarantee. Check them out here and if you have any questions, please reach out to our customer service team at 239-848-6757.

  • MCS Alpha 16" AR15 Complete Build Kit MCS Alpha 16" AR15 Complete Build Kit

    Alpha 16" AR15 Complete Build Kit

    16" Alpha Complete Upper Build Kit Minus Lower Features: BCA 16'' M4 Contour 1:7 Twist Barrel Bird cage MuzzleCarbine Length Gas TubeLow Profile .750 Gas Block15'' M-LOK Free Float Handguard Mil Spec Dust CoverForward Assist Mil-spec lower...

    MSRP: $575.99
    $479.99
    Add to Cart
  • MCS Cobra 16" AR15 Complete Build Kit MCS Cobra 16" AR15 Complete Build Kit

    Cobra 16" AR15 Complete Build Kit

    16" Cobra Complete Upper Build Kit Minus Lower Features: BCA 16'' M4 Contour 1:7 Twist Barrel Bird cage MuzzleCarbine Length Gas TubeLow Profile .750 Gas Block15'' M-LOK Free Float Handguard Mil Spec Dust CoverForward Assist Mil-spec lower...

    MSRP: $575.99
    $479.99
    Add to Cart
  • SALE
    MCS AR15 Upper Receiver 10.5" .223 5.56 NATO MLOK

    AR15 Upper Receiver 10.5" .223 5.56 NATO MLOK

    Our complete AR15 5.56 upper comes FULLY ASSEMBLED with a 5.56 NATO barrel, capable of shooting both .223 and 5.56. With an Anchor Harvey Upper and an MCS Hand Guard, this will make your next build the ultimate AR. Includes: ANCHOR HARVEY Upper...

    MSRP: $320.99
    Was: $310.99
    Now: $290.99
    Add to Cart
  • SALE
    MCS AR-15 Upper Receiver 7.5" 5.56 NATO MCS AR-15 Upper Receiver 7.5" 5.56 NATO

    AR-15 Upper Receiver 7.5" 5.56 NATO

    Our complete AR15 5.56 upper comes FULLY ASSEMBLED with a 5.56 NATO barrel, capable of shooting both .223 and 5.56. With an Anchor Harvey Upper and an MCS Hand Guard, this will make your next build the ultimate AR. Includes: ANCHOR HARVEY Upper...

    MSRP: $330.99 - $335.99
    $289.99 - $295.99
    Choose Options
  • SALE
    MCS 10.5" 5.56 NATO BARREL GOVT CARBINE LENGTH 1:7 MCS 10.5" 5.56 NATO BARREL GOVT CARBINE LENGTH 1:7

    10.5" 5.56 NATO BARREL GOVT CARBINE LENGTH 1:7

    10.5" 5.56 NATO BARREL GOVT CARBINE LENGTH 1:7 LENGTH: 10.5" PROFILE: GOVT GAS SYSTEM: CARBINE LENGTH TWIST RATE: 1:7 GAS BLOCK:  .750" MATERIAL: 4150V WEIGHT: 19.3 OZ. MUZZLE: 1/2-28 THREAD FINISH:  BLACK NITRIDE USA Made

    MSRP: $110.99
    Was: $100.99
    Now: $88.99
    Add to Cart
  • SALE
    MCS AR-15 16" 5.56 NATO UPPER W/O BCG MCS AR-15 16" 5.56 NATO UPPER W/O BCG

    AR-15 16" 5.56 NATO UPPER W/O BCG

    Our complete AR15 5.56 upper comes FULLY ASSEMBLED with a 5.56 NATO barrel, capable of shooting both .223 and 5.56. With an Anchor Harvey Upper and an MCS Hand Guard, this will make your next build the ultimate AR. Includes: ANCHOR HARVEY Upper...

    MSRP: $399.99
    Was: $375.99
    Now: $314.99
    Choose Options