Armaspec Sound Mitigation Buffer (SMB) Captured Gen 3 - Multiple Buffer Weights Available
or 4 interest-free payments of $13.50 with 
6 Magazines Per Order: Due to extreme volume, we are limiting sales of magazines to 6 per customer order. This applies to individual and bundled magazines. AT3 reserves the right to cancel any order over the 6 magazine limit.
- Free standard shipping on orders $139+ details
- 90-day no-hassle returns policy
- Backed by the Armaspec Lifetime Warranty! what it covers
Frequently bought together
From orders that included this item
Product description
Improved & Easy-To-Install Captive Buffer Weights For AR Builds
The Armaspec Sound Mitigation Buffer (SMB) Captured Gen 3 is a quick and easy replacement for your standard buffer and spring. It is designed to keep the buffer spring from rubbing against the inner wall of the buffer tube providing smooth and consistent operation as well as providing less noise when firing the weapon.
The SMB also helps significantly in reducing the felt recoil which results in an excellent return to target acquisition, giving the shooter more accurate follow-up shots.
Multiple Buffer Weights
The Armaspec Sound Mitigation Buffer (SMB) Captured Gen 3 is available in different buffer weights such as Carbine, Heavy, H2, H3, 9MM, and AR-10. (Please choose in the dropdown above for the correct buffer weight).
Note For 9MM: For proper function of the SMB in your 9mm rifle or pistol, the extra weight on the back of the bolt carrier needs to be removed. It is held in with a spring/roll pin.
Features:
Specifications:
- Actual Weight (Complete System):
- Carbine: 4.41 oz.
- Heavy: 4.91 oz.
- H2: 5.81 oz.
- H3: 6.71 oz.
- 9MM: 9.88 oz.
- AR-10: 7.20 oz
- Equivalent Weight:
- Carbine: 3.3 oz.
- Heavy: 3.8 oz.
- H2: 4.7 oz.
- H3: 5.6 oz.
- 9MM: 6.9 oz.
- AR-10: 4.7 oz
Includes:
- 1x Polymer Base Guide Rod
- 1x Spring
- 1x Buffer
Quick Instructions:
- Insert polymer base with guide rod into the buffer tube.
- Insert desired spring on the guide rod.
- Insert the buffer over the spring.
All 6 options on this page
- Armaspec Sound Mitigation Buffer (SMB) Captured Gen 3 - Multiple Buffer Weights Available - Buffer Weight: Carbine SKU ARM258-C · UPC 810048492435
- Armaspec Sound Mitigation Buffer (SMB) Captured Gen 3 - Multiple Buffer Weights Available - Buffer Weight: Heavy SKU ARM258-H · UPC 810048492442
- Armaspec Sound Mitigation Buffer (SMB) Captured Gen 3 - Multiple Buffer Weights Available - Buffer Weight: H2 SKU ARM258-H2 · UPC 810048492459
- Armaspec Sound Mitigation Buffer (SMB) Captured Gen 3 - Multiple Buffer Weights Available - Buffer Weight: H3 SKU ARM258-H3 · UPC 810048492466
- Armaspec Sound Mitigation Buffer (SMB) Captured Gen 3 - Multiple Buffer Weights Available - Buffer Weight: 9mm SKU ARM258-9 · UPC 810048492473
- Armaspec Sound Mitigation Buffer (SMB) Captured Gen 3 - Multiple Buffer Weights Available - Buffer Weight: AR-10 SKU ARM258-AR10 · UPC 810048492480
Customer reviews 28
Verified buyerRun to get rid of that spring sound you get when firing ARs, plus i I got it on sale and steal!
AT3 Tactical · We’re thrilled the SMB is giving you that butter-smooth action at a fraction of the cost, David, and we hope you have an absolute blast testing it out at the range with your new setup!
Installed on my PSA 16" AR-15, swapped out the carbine weight buffer with the H3. It shoots .223 55 grain Hornady ammo reliably and ejects casings at the 3 O'clock position.
Questions & Answers 15
-
Will this work for a 50 beowulf
Adam · Jun 12, 2026AT3 Support Team — Yes, it will work for a .50 Beowulf, but you should use the H3 weight (approx. 5.6 oz) to handle the heavy recoil of that specific cartridge.
-
Will this work with 50 beowulf 16"
Adam · Jun 12, 2026AT3 Support Team — Yes, it works with a 16″ .50 Beowulf, but you must use the H3 weight (5.6 oz) to safely handle the heavy direct recoil.
-
With a suppressed 20” barrel should I use an H1 or carbine? I’m torn. Or should I get an adjustable gas block?
Greg Ray · Apr 14, 2026AT3 Support Team — I would recommend an adjustable gas block with bleed off and H1 weight Thanks
-
I have a 7.5in .300blk pistol. Would it be better to use a Heavy or H2 on it?
Jacob · Jan 10, 2026AT3 Support Team — For your unsuppressed 7.5" .300 BLK pistol, go with the H2 (4.6oz) Armaspec SMB Gen3—it's the sweet spot for short barrels. The H2 tames high bolt speeds from the short gas system better than Heavy (5.4oz), preventing over-gassing while reducing recoil and twang. Heavy works for suppressed/subsonic-heavy setups, but H2 ensures reliable supersonic function!
Warranty & returns
Backed by the Armaspec Lifetime Warranty!
Armaspec Lifetime Warranty
- All Armaspec products carry a LIFETIME WARRANTY and are warranted to be free from defects in material or workmanship.
- Should there be a defect, we will repair or replace the product at our discretion at no cost to you.
- Lifetime warranty does not apply to products sold as “blemished” or “manufacturer refurbished”.
- You must have proof of purchase to initiate a WARRANTY claim.
Please email to rma@armaspec.com to request an RMA number.
Disclaimer: Manufacturer’s warranty is subject to change without prior notice.
90-day no-hassle returns
The AT3 Tactical store has a 90 day no-hassle return policy for products in good condition. You can view the full details of our return policy here.
If you encounter an issue or defect with a product after 90 days of your purchase, you can refer to the manufacturer for a warranty claim. Their policies are below.
