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    YHM Lightweight Free Float Quad Rail YHM-9631 9638 9636 Forearm
    YHM Lightweight Free Float Quad Rail YHM-9631 9638 9636 Forearm
     $134.00  $92.95 
    Manufacturers Info
    Rainier Arms
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    Rainier Arms Thunder Bolt Carrier Group BCG HPT/MPI/Shot Peened [RA-BCG]  $159.95  $138.95 

    Rainier Arms Thunder Bolt™ BCG HPT/MPI/Shot Peened AR15 M16



    The Thunder Bolt™ BCG was created to meet and exceed all Mil Spec standards. Giving you the confidence to run your weapon long and hard at 110%. You will never have to worry about your BCG being the weakest link in your weapon. The bolts are HPT & MPI tested & Marked to give you ultimate confidence in your weapon system.


    • SAE 8620
    • Heat Treated
    • Manganese Phosphate with Hard Chrome Lined Bore


    • Carpenter A-158
    • Shot Peened
    • Heat Treated
    • Manganese Phosphate Coating


    • Machined from bar
    • Shot Peened
    • Heat Treated
    • Maganese Phosphate Coating

    Extractor Spring:

    • Chrome Silicone for Longer Life
    • Black Insert as per current Mil-Spec
    • “O” Ring is high temp resistant dark brown

    Extractor Retaining Pin:

    • Precision Machined
    • Precision ground to diameter
    • Precision ground to length
    • Heat Treated

    Firing Pin:

    • Machined and then precision ground for accuracy
    • Heat Treated
    • Hard Chrome Plated

    Gas Key Bolt:

    • Precision manufactured in house with extra deep knurling
    • Grade 8
    • 1200 degree locking patch is factory applied to threads to help insure long lasting tightness

    Gas key:

    • Hard Chrome lined gas tube as per Mil-Spec
    • Bolts installed to proper torque
    • Staking on both sides of both bolts

    Cam Pin:

    • Precision machined
    • Heat Treated
    • Maganese Phosphate Coating

    Firing Pin Retaining Pin:

    • Precision bent
    • Precision cut to length
    • Heat Treated

    Gas Rings:

    • Stainless Steel per Mil-Spec


    • Precision machined
    • Heat Treated

    Ejector Spring:

    • Chrome Silicone
    • Precision ground ends

    Ejector Retaining Pin:

    • Precision cut to length
    • Black Zinc Coating

    Limited Lifetime Warranty
    We are so confident in our Rainier Arms Thunder Bolt BCG we offer them with a limited lifetime warranty. So if at anytime your Rainier Arms Thunder Bolt BCG breaks on your during normal use(Intentional abuse & Gas Key wear not included) we will replace it.

    *We have “toned down” the logos due to customer response and lowered the price for your benefit.


    This product was added to our catalog on Saturday 26 March, 2011.
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