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Rifle Parts

Whether you're building a new rifle from scratch or looking to upgrade an existing firearm, our vast selection of rifle parts has everything you are going to need in that journey. At Rainier Arms' selection of rifle parts, you can find a wide variety of products including lower and upper parts, trigger parts, muzzle devices, and many more. 

Explore our selection of high-quality parts coming from various leading manufacturers like Strike Industries, Magpul, BCM, and many more.

Also, don't forget to check our specially-made Rainier Arms barrels for your firearms.

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  1. Bravo Company MFG (BCM) AR-15 Upper Receiver 9" 300 BLACKOUT MCMR-8
    Bravo Company MFG (BCM) AR-15 Upper Receiver 9" 300 BLACKOUT MCMR-8
    $731.45
    Out of stock
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  2. SIG SAUER MCX Rattler 300BLK Complete Upper - 5.5"
    SIG SAUER MCX Rattler 300BLK Complete Upper - 5.5"
    Special Price $1,759.99 Regular Price $1,999.99
    Out of stock
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  3. Bravo Company MFG (BCM) MK2 Standard 300 BLACKOUT Upper Receiver Group w/ MCMR-8 Handguard - 9"
    Bravo Company MFG (BCM) MK2 Standard 300 BLACKOUT Upper Receiver Group w/ MCMR-8 Handguard - 9"
    $743.49
    Out of stock
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  4. Rainier Arms Exclusive Faxon Firearms 300BLK Chrome Lined 4150 5R Barrel - 8.5"
    Faxon Firearms 300BLK Chrome Lined 4150 5R Barrel - 8.5"
    $189.00
    Out of stock
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  5. V Seven Weapon Systems 300BLK Fluted Barrel w/ Ti Gas Block - 6.5"
    V Seven Weapon Systems 300BLK Fluted Barrel w/ Ti Gas Block - 6.5"
    $395.76
    Out of stock
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  6. Fortis MFG Muzzle Brake 300BLK Nitride
    Fortis MFG Muzzle Brake 300BLK Nitride
    $75.95
    Out of stock
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  7. Primary Weapons Systems 300 BLK MK1 MOD 2-M Complete Upper - 9.75"
    Primary Weapons Systems 300 BLK MK1 MOD 2-M Complete Upper - 9.75"
    $1,299.95
    Out of stock
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  8. Ballistic Advantage Modern Series 300BLK Barrel - 9"
    Ballistic Advantage Modern Series 300BLK Barrel - 9"
    $152.00
    Out of stock
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  9. Primary Weapons Systems 300 BLK MK109 MOD 1-M Complete Upper - 9.75"
    Primary Weapons Systems 300 BLK MK109 MOD 1-M Complete Upper - 9.75"
    $1,029.49
    Out of stock
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  10. Bootleg Mil Spec AR-15 300BLK CamLok (M-Lok) Partial Upper - 8.5"
    Bootleg Mil Spec AR-15 300BLK CamLok (M-Lok) Partial Upper - 8.5"
    $489.00
    Out of stock
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  11. Ballistic Advantage Modern Series 300BLK Barrel - 10.5"
    Ballistic Advantage Modern Series 300BLK Barrel - 10.5"
    $156.75
    Out of stock
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  12. Maxim Defense MDX 505 PDX 300BLK Mil-Spec Complete Upper - 5.5" Urban Grey
    Maxim Defense MDX 505 PDX 300BLK Mil-Spec Complete Upper - 5.5" Urban Grey
    $1,165.50
    Out of stock
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  13. Aero Precision M4E1 300BLK Complete Upper Receiver w/Atlas R-ONE Handguard - 8" Black
    Aero Precision M4E1 300BLK Complete Upper Receiver w/Atlas R-ONE Handguard - 8" Black
    $534.99
    Out of stock
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  14. Faxon Firearms Match Series AR-15 Gunner 300BLK 416R QPQ Nitride Barrel
    Faxon Firearms Match Series AR-15 Gunner 300BLK 416R QPQ Nitride Barrel
    Out of stock
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  15. Spinta Precision AR-15 300BLK Cold Hammer Forged Barrel - 8" (Limited Production)
    Spinta Precision AR-15 300BLK Cold Hammer Forged Barrel - 8" (Limited Production)
    Special Price $149.99 Regular Price $199.99
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  16. Maxim Defense MDX 508 300 BLK Mil-Spec Complete Upper - 8.5"
    Maxim Defense MDX 508 300 BLK Mil-Spec Complete Upper - 8.5"
    Out of stock
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