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ar upper

The AR-57, also known as the AR Five Seven , is a Lower receiver for the AR-15/M16 rifle and an Upper receiver, firing 5.7×28mm rounds from standard FN P90 magazines. It was designed by AR57 LLC and is currently produced by AR57 of Kent, Washington, USA. The AR-57 PDW Upper is a new design on AR-15/M16 rifles, blending the AR-15/M16 lower with a lightweight, monolithic upper receiver system chambered in FN 5.7×28mm. This model is also sold as a complete rifle, supplied with two 50-round P90 magazines. The magazines mount horizontally on top of the front handguard, with brass ejecting through the magazine well. Hollow AR-15 magazines can be used to catch spent casings.
Unlike the standard AR-15 configuration which uses a gas-tube system, the AR-57 cycles via straight blowback. A full auto version exists marketed as a competitor to the P90 and other personal defense weapons.

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Recent contents
  1. Lilhigbee

    Olympic Arms 9mm 16" AR upper w/ 2 magazines.

      1. For Sale
    • $500
    • Potland
    • Oregon
    For your consideration I have an Olympic Arms AR upper in 9mm with a 16" barrel. The upper is complete with BCG, charging handle, A2-style sights, flash hider, etc. The two mags are converted Sten mags which is what Olympic did for their first 9mm ARs. Upper is in excellent condition with a...
  2. baseballplerrr

    Done  BCA 16inch complete AR upper with BCG/handle $161 shipped

    Ended.
  3. Dylan323i

    DJHT 50 BMG UPPER SCREW IN STYLE BOLT AR UPPER

      1. For Sale
    • $650
    • Springfield
    • Oregon
    Selling my 50 bmg upper. Mounts directly to any standard ar15 style lower the lower acts as the trigger assembly. Barrel according to the manufacturer is off of an M2. Bolt is a screw in design with a 3/8" Ratchet
  4. S

    S&W MP15 AR Upper in 5.45x39 + Mags

      1. For Sale
      2. For Trade
    • $300
    • Portland
    • Oregon
    Smith & Wesson M&P15R complete upper chambered in 5.45x39 16" Handguard is brand new Includes 8x C-Pro AR Mags made for 5.45x39 $300 Will trade for: Red dot (Preferably XPS2, Holosun, or maybe Vortex) Lee Enfield 303 possible consideration for other rifles or pistol if something catches my eyes.
  5. K

    7.62x39 AR Upper

      1. For Sale
    • $275
    • Kalispell
    • Montana
    PSA KS-47 8" upper with M-Lok handguard. Never been fired and includes bolt carrier group, charging handle, and 10 rd C-products 7.62x39 mag. Compatible with a standard 5.56 AR lower. Does not include optics. Please let me know if you have any questions. Prefer local meet up and not really...
  6. M

    AR upper parts. Barrel, gas block BCG

      1. For Sale
      2. For Trade
    • $150
    • Kelso
    • Washington
    Pretty standard uses parts. 16" 1:7twist 556 Nato barrel, bcg and gas tube and block. Open to trades
  7. HINZERD

    Random AR upper stuff, Geissele trigger, Cloud owl, and a COOLER!!!

      1. For Sale
    • $450
    • Gladstone
    • Oregon
    I have been a packrat for the better part of a decade, and finally got around to finishing an AR upgrade and cleaning my workstation. There is a mix of stuff in here, best represented in the photos. The money item is definitely the cooler! Cloud defensive OWL, works fine but could use a deep...
  8. corsar66

    PSA AR 16" upper, No BCG or Ch. handle

      1. For Sale
    • $220
    • Happy Valley
    • Oregon
    Used PSA upper with around 400 rounds trough, No BCG or Charging handle, Barrel: Nitride finished 4150V chrome moly vanadium 16" barrel. Chambered in 5.56 NATO, with a 1:7 twist, M4 barrel extension, and a carbine-length gas system. Barrel is is finished off with Magpul MOE carbine-length...
  9. ar man

    inexpensive ar upper

      1. Want to Buy
      2. Want to Trade For
    • Keizer
    • Oregon
    Titles says it all looking for a complete upper that some one might have for sale for a project dose not have to be top shelf all ready have a couple of them just need one for a lower I have laying around. Will be ordering a bca on Monday if not pistol or rifle is fine. Just would rather keep...
  10. WHO

    BUSHMASTER HEAVY BARREL NIB w Colt AR Upper & Bolt Carrier

      1. For Sale
    • $315
    • Silverton
    • Oregon
    Colt AR 15 upper never assembled Accompanied by never mounted FLUTED Bushmaster Heavy Barrel And Carrier w Bolt which has been minimally fired Bushmaster is 1/9 MINT NIBag Marked B. M. P 5.56. NATO 1/9. HBAR Interesting barrel made in the Old days shiny mint bore and threads Great cap to...
  11. robertvarner

    Atheris 6ARC AR Upper Receiver

      1. For Sale
    • $375
    • Camas
    • Washington
    Atheris 6ARC 20" AR Upper. I can meet the buyer between Longview and Wilsonville. $375 cash Please PM me if you have questions or are interested, so I can keep this thread clean.. I bought this several years ago, but I changed direction. Only has approximately 100 rounds through it. Includes...
  12. Rob86

    Aero 11" AR upper

      1. For Sale
      2. For Trade
    • $349
    • Canby
    • Oregon
    Aero Precision 11" AR-15 upper for sale. No BCG/CH. Low round count. .223. Aero S1 handguard, Epsilon VG6 muzzle break. Good condition. I am open to hearing trade offers. Thank you
  13. Rob86

    .300 blackout AR upper

      1. For Sale
      2. For Trade
    • $199
    • Canby
    • Oregon
    Hello, I have an Anderson brand 8” barrel AR upper in .300BO for sale. Asking $199 obo I am willing to hear trade offers. Thank you
  14. arakboss

    AR Upper Palooza For 2025/26

    What is your latest AR upper project you've bought, built, or have parts to build? I think 2025/26 are going to be the years of AR upper projects in my life. I have many upper projects from piles of parts to complete uppers. My plan is to work on one or two at a time. Once I have a complete...
  15. tdemore1743x

    10.5in AR upper for shorter upper

      1. For Trade
    • Hoquiam
    • Washington
    I recently acquired this upper for a folding backpack gun, but turns out it’s too long for the backpack I want to carry. So I’m looking to trade this for a 7.5 or shorter
  16. NWRider

    - AR Upper Parts

      1. Want to Buy
      2. Want to Trade For
    • Vancouver
    • Washington
    Have barrel, gas block and tube. Need everything else. Looking for 13" for rails. Also looking for an adjustable stock, 3x magnifiers, red dots (rifle & pistol {rmr footprint}), weapon light. Have glock parts, long range gear, some ammo, motorcycle gear and other misc. could trade. Or cash...

  17. PSA 18" AR Upper 5.56

      1. For Sale
      2. For Trade
    • $240
    • vancouver
    • Washington
    18" heavy barrel PSA upper. Is a "blem" no obvious blemish. Unfired. No BCG/CH. $240. Or following trade - - AMMO - - 10mm, 9mm, .308, 5.56, 22lr - FIREARMS - single stack Glock 380/9mm models - g42/g43/g43x - Ruger LCP Max
  18. BrandoCommando

    AR Ripcord Industries 13.9 Upper Build

      1. For Sale
    • $650
    • Puyallup
    • Washington
    Very lightly used Ripcord Industries AR upper build. MSP Armory Upper receiver with dust cover and forward assist Ripcord Industries LDR1 13" rail in OD Green Criterion 13.9" Core barrel .223 Wylde Ripcord industries .625 gas block, checked and set by boatman gunworks during pin and weld. SOLGW...
  19. tdemore1743x

    7.5 side charging AR pistol upper

      1. For Sale
      2. For Trade
    • $200
    • Olympia
    • Washington
    Up for sale/trade is a Bear Creek Arsenal 7.5" .223 Wylde side charging upper. (can shoot 5.56 and .223) Selling this so I can replace it with a shorter upper. Looking to get $200 + shipping so $230 all together or best offer. Would also trade for a shorter barrel upper on 5.56.
  20. J

    Ammo for ar upper or Glock parts

      1. For Sale
      2. For Trade
    • $400
    • Olympia
    • Washington
    CORRECTION 420- rounds of 5.56 on stripper clips with a ar-15 mag loader to use strippers to load mags in ammo can 100 - rounds 9mm 150 - rounds of 5.7 140 - rounds of 30-30 50 - rounds of 12 gauge birdshot 100 - rounds .38 20 - 762x39 50 - .44-40 I'm sure there is more. I also have a p80 g17...
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