Description
9mm AR builds have a reputation for feeling a little sharper and louder than their 5.56 cousins, and that comes down to how the blowback action cycles. Armaspec built the ARM263-9 kit to deal with exactly that. Instead of running a standard buffer and spring, this kit drops in their Gen4 Stealth Recoil Spring tuned specifically for 9mm, along with the mil-spec buffer tube, castle nut, and end plate needed to get a stock mounted from scratch.
What the SRS-9 Buffer Does Differently
The SRS-9 is a self contained, multi-stage spring and buffer assembly that replaces the traditional loose spring setup. It keeps constant tension against the bolt carrier and is designed to stop the spring from rattling around inside the tube, which cuts down on that metallic twang you get on a lot of stock 9mm builds. The second stage of the spring is what takes the edge off felt recoil, so cycling feels a bit more controlled and a lot quieter, especially noticeable on a blowback action running at a quick cadence.
Buffer Tube Kit Built for the Long Haul
Rounding out the ARM263-9 kit is a 6-position buffer tube machined from 7075-T6 aluminum, plus a steel castle nut and steel end plate. That combination gives you a mil-spec platform for mounting basically any adjustable stock without hunting down extra hardware. Every piece is made in the USA and backed by Armaspec's lifetime warranty against defects in material or workmanship.
One thing worth knowing before installing: 9mm bolt carriers typically have an extra weight pinned to the rear that needs to be removed for the SRS-9 to seat and function correctly. It is a quick fix with the right tools, and once it is out the SRS-9 drops right in without needing the factory buffer retainer, though it will work with or without one if you prefer to keep it in place.
Key Specifications
- Manufacturer: Armaspec
- Manufacturer Part Number: ARM263-9
- UPC: 810048492886
- Buffer System: Stealth Recoil Spring (SRS) Gen4, SRS-9
- Buffer Length: 7.18 inches
- Buffer Actual Weight (Complete System): 8.40 oz
- Buffer Equivalent Weight: 5.4 oz
- Buffer Tube Material: 7075-T6 Aluminum
- Buffer Tube Type: Mil-Spec, 6-Position
- Castle Nut: Steel
- End Plate: Steel
- Color: Black
- Compatible Platform: AR-15/AR9 9mm builds with carbine-length buffer tube
- Country of Origin: Made in USA
- Warranty: Lifetime against defects in material and workmanship
What’s Included
- Armaspec SRS-9 Gen4 buffer
- Mil-spec 7075-T6 6-position buffer tube
- Steel castle nut
- Steel end plate
Frequently Asked Questions
What makes the SRS-9 buffer different from a regular 9mm buffer?
The SRS-9 is a self contained, multi-stage spring and buffer assembly rather than a loose spring and weight. It stays under constant tension against the bolt carrier, which keeps the spring from rattling against the tube wall and takes some of the sting out of felt recoil during cycling.
Does this kit come with a stock?
No, this kit covers the buffer tube, castle nut, end plate, and SRS-9 buffer, which is everything needed to mount a stock. The stock itself is sold separately, so pick whichever adjustable stock fits your build.
Do I need to modify my bolt carrier to run the SRS-9?
Most 9mm bolt carriers have an extra weight pinned to the rear that has to be removed before the SRS-9 will seat and cycle properly. It is held in with a small spring pin and comes out fairly easily with basic tools.
Will this fit a standard AR-15 lower, or is it AR9 specific?
The buffer tube itself is a standard mil-spec 6-position tube, so it fits any mil-spec lower receiver. The SRS-9 buffer is tuned specifically for the recoil impulse of a 9mm blowback action, so it is meant to be paired with an AR9 build rather than a 5.56 rifle.





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