Building a new AR-9 or AR-45? The Smith Defense AR-15 Buffer Tube Kit gives you everything required to attach any mil-spec compatible stock to your lower receiver, no hunting for parts or fretting over fitment. This kit simplifies installation and gets your build moving fast.
Inside the kit, you’ll find a 6-position Mil-Spec receiver extension made from 7075-T6 aluminum, a 7.5 oz buffer assembly, a buffer spring, and a steel castle nut with matching steel end plate. Each component is selected for reliable function and long service life, so you get a clean, secure installation without compatibility guesswork.
What’s included:
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Mil-Spec 7075-T6 Aluminum 6-Position Carbine Receiver Extension (buffer tube)
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Buffer assembly — 7.5 oz
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Buffer spring
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Steel castle nut
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Steel end plate
Quick to install, built to Mil-Spec standards — the Smith Defense Buffer Tube Kit is the convenient, reliable choice for finishing your AR-9 or AR-45 build.
