What is the difference between the Armaspec SRS and SMB?

SRS (Stealth Recoil Spring) is a captured recoil system designed as a drop-in replacement for a standard buffer and spring. SMB (Sound Mitigation Buffer) is a captured buffer option focused on smoothing cycling and reducing spring noise.

Will a captured system reduce buffer spring noise?

Captured recoil systems can reduce the spring twang many shooters notice because the spring is contained and guided rather than rubbing inside the buffer tube.

Is installation difficult?

Installation is typically similar to swapping a standard buffer and spring. Always confirm you are using the correct platform-specific model for your build.

Do I need a complete buffer kit or just the recoil assembly?

Choose a complete kit if you are building a lower or replacing tube hardware. Choose the recoil assembly if your buffer tube and hardware are in good condition and you only want to upgrade the recoil system.

Will it fit AR-10 or 9mm builds?

Use the platform-specific versions listed for AR-10/.308 and AR9/9mm. This is the best way to avoid fitment and cycling issues.

Armaspec Buffer Systems: SRS GEN4 & SMB GEN3

Armaspec SMB Sound Mitigation Buffer

Armaspec SRS vs SMB

Armaspec SRS Stealth Recoil Spring

**Armaspec Sound Mitigation Buffer SMB H3 (5.6 oz Equivalent) Gen 3** $58.18

**Armaspec Sound Mitigation Buffer SMB H2 - Gen 3** $58.18

**Armaspec Sound Mitigation Buffer SMB-H 3.8 oz for AR-15** $58.18

**Armaspec Sound Mitigation Buffer GEN3 SMB-C 3.3oz (Carbine)** $58.18

**Armaspec Sound Mitigation Buffer SMB for AR-10 GEN3** $58.18

**Armaspec Stealth Recoil Spring SRS-H3 5.6 oz for AR-15** $80.26

**Armaspec Sound Mit Buffer Ar9 Gen 3** $58.18

**Armaspec Stealth Recoil Spring SRS-H2 4.7 oz for AR-15** $80.26

**Armaspec Stealth Recoil Spring SRS-H 3.8 oz for AR-15** $80.26

**Armaspec Stealth Recoil Spring SRS-C Gen 4 — 3.3 oz Equivalent** $80.26

**Armaspec Stealth Recoil Spring SRS-BB Gen 4 for Big Bore AR-15** $80.26

**Armaspec Stealth Recoil Spring SRS AR-15 Kit Gen 4 (C, H, H2)** $102.32

**Armaspec Stealth Recoil Spring SRS-9 Gen 4 for 9mm — 6.4 oz Equivalent** $80.26

**Armaspec Stealth Recoil Spring SRS AR-10 GEN4** $80.26

**Armaspec SMB Buffer Kit AR-15 GEN3 H3** $89.96

**Armaspec SMB Buffer Kit for AR-15 Gen 3 H2** $89.96

**Armaspec Smb Buffer Kit H Gen 3** $89.96

**Armaspec Smb Buffer Kit C Gen 3** $89.96

**Armaspec SMB Buffer Kit AR10 GEN3** $89.96

**Armaspec SMB Buffer Kit AR15 GEN3 9mm** $89.96

**Armaspec Srs Buffer Kit H2 Gen 4** $112.03

**Armaspec SRS Gen 4 H3 Buffer Tube Kit** $112.03

**Armaspec Srs Buffer Kit H Gen 4** $112.03

**Armaspec Srs Buffer Kit C Gen 4** $112.03

Armaspec Buffer Systems

Q: Which weight should I start with?

If your rifle already runs well with a Carbine, H, H2, or H3 buffer, start with the closest equivalent weight in the captured system. If you are tuning, change one variable at a time.

If you’re chasing a smoother recoil impulse, less “spring noise,” and more consistent cycling, a captured recoil system is one of the cleanest upgrades you can make. Quiet, smooth cycling—without changing your buffer tube.

On this page you’ll find Armaspec’s most popular options:

SRS GEN4 (Stealth Recoil Spring) assemblies
SMB GEN3 (Sound Mitigation Buffer) assemblies
Complete buffer kits (tube + hardware + captured system) for common platforms

Quick links: AR-15 options • AR-10/.308 options • AR9/9mm options • Buffer kits

What you’re actually choosing between

SRS GEN4 (Stealth Recoil Spring)

A multi-stage, self-contained recoil assembly meant to replace a traditional buffer + spring setup and help the rifle feel more controlled during fast strings.

SMB GEN3 (Sound Mitigation Buffer)

A single-stage captured system that focuses on smoothing the feel and reducing noise while keeping the setup straightforward.

If you’re not sure, a simple rule of thumb:

Choose SRS when you want the “most refined” feel
Choose SMB when you want a simple captured system and you already know the weight you prefer

Compare the options at a glance

Feature	SRS GEN4	SMB GEN3
Best for	Smoother feel across a wider range of setups	Simple captured upgrade
Stages	Multi-stage	Single-stage
How you pick	Choose weight for your build	Choose weight equivalent for your build
Typical buyer	Wants the most “premium” recoil feel	Wants straightforward improvement

How to pick the right weight (fast guide)

Most builds run best when the weight matches your gas/buffer setup. If you’re already using a standard carbine / H / H2 / H3 buffer, you can usually start with the same equivalent in a captured system and fine-tune from there.

Common SMB equivalents (approximate):

Carbine equivalent: ~3.3 oz
H equivalent: ~3.8 oz
H2 equivalent: ~4.7 oz
H3 equivalent: ~5.6 oz
9mm option: ~6.8 oz

Tip: If your rifle feels “snappy” and ejects aggressively, you often benefit from stepping heavier. If it feels sluggish or short-strokes, you may need to step lighter or address gas.

Shop by platform

AR-15

The most common use case. Pick your preferred equivalent weight and decide whether you want a complete kit or the captured assembly.

AR-10 / .308

Heavier recoil and different cycling characteristics make platform-matched options important. Stick with the AR-10-specific versions listed here rather than guessing.

AR9 / 9mm PCC

9mm builds can be picky. Start with the 9mm-specific option shown in this category and only change one variable at a time if you tune.

Why buy from Mounts Plus

You’re not just buying a part, you’re buying the “right part the first time.” If you’re unsure which weight fits your setup, our team can help you narrow it down quickly.

FAQ

What’s the difference between SRS and SMB?

SRS GEN4 is a multi-stage captured recoil assembly designed as a drop-in replacement for a standard buffer and spring, while SMB GEN3 is a single-stage captured option focused on smoothing operation.

Which weight should I start with?

If your current build runs well on a Carbine/H/H2/H3 buffer, start with the same equivalent. For SMB, the common equivalents range from ~3.3 oz (carbine) up to ~5.6 oz (H3), with a heavier 9mm option around ~6.8 oz.

Will this reduce buffer spring noise?

Captured assemblies are designed to keep the spring from rubbing inside the buffer tube, which can reduce that “twang” and feel smoother during cycling.

Is it hard to install?

Most setups install like a normal buffer/spring swap. If your build uses a non-standard receiver extension length, you may need an appropriate spacer or a platform-specific kit.

Do I need a complete buffer kit or just the captured assembly?

Choose a kit if you’re building from scratch or replacing worn tube hardware. Choose the assembly if your current tube and hardware are in good shape and you only want the recoil system upgrade.

Will it fit my AR-10 or 9mm build?

Use the platform-specific versions listed on this page (AR-10 for .308-pattern rifles and AR9/9mm for PCCs). That’s the safest way to avoid mismatches.

Armaspec Buffer Systems: SRS GEN4 & SMB GEN3