Carbine Buffer Tube / Receiver Extension- Commercial 4 Position

Brand :

(2 reviews) Write a Review
MSRP: $24.95
(You save $5.00 )
4POS Commercial


Commercial sizes:

  • 4 position Commercial Size (Made in USA, 7075)


Note: Milspec and Commercial Sizes are not compatible with each other - they are different sizes. Commercial size should only be chosen if you know for sure you have an old Commercial sized Stock or replacing the same. Everyone else should choose Milspec since that is the long establish Standard by now and is the only size the US Military has ever used.


Aluminum, 7075 except where noted

Made in the USA, except where noted

Lifetime Guarantee

  • 4

    Posted by John W on 25th Mar 2021

    Great quality--it made my build.

  • 5
    Perfect Replacement for Old Commercial Extension

    Posted by JCFlag on 14th Jul 2019

    My Frankford Arsenal machinegun had a commercial diameter buffer tube that was too long (allowed BCG gas key to strike lower receiver under recoil) and the stock adjustment holes were worn out. I ordered the 4 position commercial tube from RetroRifles. It fit perfectly inside the fiberlite stock and threaded easily into the receiver. The length is correct so the gas key cannot strike the receiver. Best part, the back end is straight up and down, not canted like other commercial diameter buffer tubes. Thanks RetroRifles.