The Armaspec SMB Buffer Kit for AR9, Gen 3 (brand part no. ARM268-9) is a complete drop-in buffer upgrade built around Armaspec’s Sound Mitigation Buffer (SMB) system, sized specifically for 9mm AR-platform builds. Armaspec tuned this version’s mass for the blowback operating system used by AR9 carbines, which cycles differently than a gas-impingement 5.56 AR and needs its own buffer weight to run smoothly and quietly. A blowback 9mm carbine that is not matched to the correct buffer weight can cycle harshly and loudly, and this SMB kit is built to correct that. It comes with everything needed to complete the buffer system, so there is no need to source a separately matched spring.

Key Specifications

• Built around Armaspec’s Sound Mitigation Buffer (SMB) design for quieter, smoother cycling than an OEM buffer.
• Sized specifically for AR9 blowback platforms, not gas-impingement 5.56 AR-15s.
• Sold as a complete buffer tube assembly kit, including the matched spring needed alongside the SMB weight.

Frequently Asked Questions

Will this fit a standard 5.56 AR-15? No, this kit is sized specifically for 9mm AR9 blowback-operated carbines, not gas-impingement 5.56 builds.

Does this kit include the spring? Yes, it is a complete buffer tube assembly with the SMB weight and its matched spring.

Buy the Armaspec SMB Buffer Kit for AR9

Quiet down and smooth out a 9mm AR carbine with a buffer system built specifically for blowback operation. Browse Schaefer Defense’s AR buffer system parts and order from our Lubbock, Texas gun shop for fast shipping.