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piston

A piston is a component of reciprocating engines, reciprocating pumps, gas compressors and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and/or connecting rod. In a pump, the function is reversed and force is transferred from the crankshaft to the piston for the purpose of compressing or ejecting the fluid in the cylinder. In some engines, the piston also acts as a valve by covering and uncovering ports in the cylinder wall.

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Recent contents
  1. T

    PWS MK111 Mod 2 Upper ONLY

      1. For Sale
    • $1100
    • Portland
    • Oregon
    If you know, you know. The PWS MK111 Mod 2 is a long stroke gas piston upper with an adjustable gas block, resulting in extreme reliability and durability, especially if running suppressed. It has around 300 rounds through it and I’m only letting it go to fund other builds. Comes with the PWS...
  2. IronSites2NS

    Sig Sauer 516 Factory Quad Rail Handguard

      1. For Sale
    • $200
    • Oregon City
    • Oregon
    For Sale is a very lightly Used and very HARD TO FIND Sig Sauer AR 516 Quad Rail Factory Hand Guard in great condition! No hardware, just the hand guard. This came off of my 516 piston upper. If you have any questions, please PM me. Cash Only. No Trades. I will ship at Buyers Expense.
  3. matfish

    BRN180 complete upper.

      1. For Sale
      2. For Trade
    • $500
    • Salem
    • Oregon
    I have an 18” 223 wylde BRN180 complete upper. piston upper with captured buffer springs. Means you can run a folding stock and no buffer tube with this upper. Around 500 rounds through upper. Does not come with lower or red dot. Trades I’m looking for, LVPO, Glock(9mm), gucci AR parts, body...
  4. wavebywave

    *** New - POF USA REVOLUTION 308 16.5" Gen 4 Rifle - Piston Driven - Burnt Bronze ***

      1. For Sale
    • $2800
    • Tigard
    • Oregon
    Hello, Up for sale is a brand new, never fired, Piston Driven POF Revolution in Burnt Bronze. I've had this rifle in a hard case (included, pictured below) for a year in a climate controlled space. It hasn't been fired and is in perfect condition - only selling because I have another kiddo on...
  5. H

    PWS Mk216 16" .308 Win Piston AR10

      1. For Sale
    • $1750
    • Centralia
    • Washington
    Like new PWS Mk216 long stroke piston AR10 with 16" barrel chambered in .308 Winchester, it has been well taken care of and has less than 40 rounds through it, there is just one minor blemish on the side of the receiver. The long stroke piston system is reliable, adjustable, and very soft...
  6. P

    Adams Arms Piston Complete Upper

      1. For Sale
    • $450
    • Kirkland
    • Washington
    Price: $450 Condition and package: Close to new condition, total 300-400 rounds through it (tested with brass and steel cased), no problems at all. Comes with all original parts and I can throw in a bag and the Lancer mag that came with it. For the Samson Manufacturing Anti-Rotation handguard...
  7. Kdawg2607

    PWS MK107 Diablo Upper - $600

      1. For Sale
    • $600
    • Everett
    • Washington
    For Sale, PWS Diablo 7.85 gen2 upper. Keymod rail, Sig micro brake/can mount, FCD F/A. About 750 rounds fired. $600
  8. Kdawg2607

    PWS AR10 (MK216) - 1500

      1. For Sale
    • $1500
    • Everett
    • Washington
    For sale, PWS MK216 16" 308. 16" barrel, Keymod rail, NiB coated BCG, adjustable piston, Silencerco ASR Brake, Magpul ACS/L stock, B5 grip, Forward Controls bolt catch, Radian Safety. Unfired. $1500
  9. BrandonQuixote

    Superlative arms piston retrofit kit

      1. For Sale
    • $200
    • Hillsboro
    • Oregon
    .625 gas journal size, set screw type, mid length piston. Comes with piston bushing for upper if needed. 30 rounds through this- decided to stick with all direct impingement for consistency with all my rifles. $200 $8 shipping Brandon 951 442 6918 text only please.
  10. eldbillbo

    Huldra Arms Ar15 Carbine 5.45.x39 Piston upper complete

      1. For Sale
    • $475
    • Oregon City
    • Oregon
    Huldra Arms 5.45.x39 Piston upper complete . Has Adams Arms coated anti-carrier with spring release bolt. I bought the upper with 300 rds on it and put a hundred rds on it . It has some strand markings on it the barrel not sure what from. I am also willing to part this upper out if someone just...
  11. pogi

    S&W MP15 PSX NIB

      1. For Sale
    • $1200
    • Gresham
    • Oregon
    Withdrawn, you suckers lose. I'm going to keep this factory gun. GL in your search. S&W MP15 PSX (gas piston system) NIB with one 30-round magazine (1 Magpul) . Will ship to your FFL (FFL must accept shipment from a non-FFL) for $50. Not looking for any trades at this time. Please post...
  12. A

    Umarex colt m4 spring piston break barrel .177 caliber pellet rifle

      1. Want to Buy
    I am looking for Umarex colt m4 spring piston break barrel .177 caliber pellet rifle
  13. czgunner

    Rifle length Superlative Arms piston kit ***SOLD***

      1. For Sale
    • $200
    • Woodland
    • Washington
    Looking to sell my low round count (20'ish) Superlative Arms piston kit in rifle length with clamp on .750" gas block and mid length with set screw .750". Looking for $200 OBO. You can change the op rod length to carbine/mid/pistol easily for $35. Available from Superlative Arms. ***MID LENGTH...
  14. ZakAri

    Christensen Arms CA-15 Piston...trade pending meet up

      1. For Trade
    • $1525
    • Portland
    • Oregon
    Christensen Arms CA-15 (excellent condition) - Piston driven AR-15/ Carbon Fiber - .223 Wylde (.223/556) - 5 - 30 rd mags - Christensen zipper case with 5 mag holders/ Velcro pouches with extra compartments More info here: CA-15 Recon and G2 Rifles Not long ago bought from a great member on...
  15. arakboss

    Sig 516 Piston Upper Chambered in 5.56. Unfired, as new in box.

      1. For Sale
    • $625
    • Westside Metro
    • Oregon
    Edit: 3/27/20: If buyer purchases my Sig 516 piston upper and my Anderson pistol lower, there will be bonus ammo included in deal, see pistol lower ad here: Anderson Lower With KAK Pistol Brace and KAK Dimpled Tube For Length Of Pull Adjustment $150 Edit: 3/19/20 price dropped to $625 Edit...
  16. matts

    Benjamin nitro piston .22 cal with scope want AR lower 100% or 80%...

      1. For Sale
      2. For Trade
    • $125
    • Vancouver
    • Washington
    Price drop.
  17. Tony617

    Quick question on the AK-47 gas piston

    I have question on the AK-47 gas piston. With my M14 you keep the gas piston and cylinder dry. Is it the same for AK-47 to keep it dry as well? What about the gas cylinder too? Just using CLP to cleaning and lubing right now. Thank you.
  18. P

    Adams Arms EVO Tactical Piston Upper

      1. For Sale
    • $550
    • Washington
    Selling the complete upper with all OEM parts: barrel, BCG, charging handle. The upper is the exact same as: Complete product information page: 16" Carbine Tactical Evo Upper Condition and package: Essentially new condition, total 200-300 rounds through it (tested with brass and steel cased)...
  19. JBSTRD

    WTS WA  Primary Weapons Systems (PWS) MK111 Mod 2 Complete Piston Factory Upper (Never Fired)

    ***SOLD*** I have a never fired factory-built PWS MK111 Mod 2 piston upper chambered in 223 Wylde. This is their 11.85” barreled Upper. If you aren’t familiar with PWS and their long stroke piston system, it is very similar in function to an AK piston. The long stroke piston eliminates...
  20. C

    Lwrc 6.8 razor back piston in bronze 5mags

      1. For Sale
      2. For Trade
    • $1800
    • Vancouver
    • Washington
    Hi have a lwrc 6.8spc 5 mags piston gun in Bronze all factory stuff have optics Leupold 4power for the right price would like to get $1800 for it if you want photo or check give me and email or photo just ask
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