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Thunder Beast Arms’ new Spiro suppressor targets gas guns with a compact 5.56 design that cuts back pressure while keeping sound levels in check. This suppressor is made from durable materials and falls between an S-length and a K-length can.
A New Direction for Gas Gun Suppressors
Thunder Beast Arms, also known as TBAC, designed the Spiro as a dedicated 5.56 suppressor for rifles that see real shooting volume. TBAC focused on reducing back pressure without letting sound signatures spike. That balance drives the entire design.
The Spiro uses a reduced back-pressure layout that increases back pressure by only about 50 percent over a bare muzzle. Many so-called low back-pressure suppressors push far more gas back into the system. On a Mk18, the Spiro only bumps the cyclic rate by roughly five percent. That helps keep guns cleaner and run smoother during longer strings.
Sound suppression by the Spiro is impressive. Shooter’s ear readings sit around 136 dBA, with muzzle numbers landing in the same range. Those results place the Spiro on the same level of performance with larger suppressors, despite its short length.
Built for Heat and Abuse
TBAC built the Spiro from Haynes 282, a nickel-based super alloy designed to handle extreme heat. The material even outperforms the venerable Inconel 718 alloy at high temperatures and resists erosion during rapid fire.
Thunder Beast rates the Spiro for heavy firing schedules. It survives over 20 cycles of the SOCOM SURG test on an 8-inch barrel. That rating goes well beyond typical “full-auto rated” claims. TBAC clearly expects this suppressor to be used and abused, and has prepared accordingly.
At 5.9 inches long and about 15.5 ounces, the Spiro fits between a K-can and an S-size suppressor. It adds roughly 5.3 inches to overall weapon length. That size works well on AR-pattern rifles from 8 to 16 inches.
Mounting, Availability, and Pricing
TBAC offers the Spiro in direct thread or HUB (1.375×24) configurations. Direct thread suits dedicated rifles and ships with a Nord-Lock washer. The HUB option supports user-preferred mounts, with a 1.6-inch thread-end-to-first-baffle distance.
The Spiro is available now. TBAC takes direct orders and supplies major distributors. MSRP sits at $995 for either mount option.
Specifications and Features
- Caliber: 5.56mm / .223
- Construction: Haynes 282 nickel-based super alloy
- Weight: 15.5 oz
- Length: 5.9 in
- Design: Low back pressure gas gun suppressor
- Sound Performance: ~136 dBA at shooter’s ear
- Recoil Reduction: ~40% vs bare muzzle
- Mount Options: Direct Thread (1/2×28), HUB (1.375×24)
- Rating: Extreme duty / full-auto
- Minimum Barrel Length (5.56): 8 in
- Intended Use: High-volume AR-pattern rifles
The Spiro isn’t only performing impressively cutting sound, but it’s also built to be ran longer and harder than most. TBAC’s Spiro focuses on gas control, durability, and size. For shooters running short-barreled 5.56 rifles hard, that focus makes sense.
Learn more about Thunder Beast’s new Spiro HERE.
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Riley Baxter is a seasoned hunter, outdoorsman, and competitive shooter with deep roots in the backcountry. He has guided professionally for bears, bighorn sheep, and other big game across rugged terrain, bringing firsthand knowledge of what gear actually works in the field. When he’s not chasing game or running drills on the range, Riley is likely in the garage customizing his rifles, pistols, or backcountry kit.
A competitive pistol shooter and lifelong firearms enthusiast, Riley brings both precision and creativity to every piece of equipment he touches. Outside of the gun world, he works as a perfusionist in Montana, a vital role in heart surgery that demands attention to detail, critical thinking, and mental fortitude.
Experience:
– Professional Hunting Guide – Guided for bears, bighorn sheep, and more in some of the West’s toughest country.
– Competitive Shooter – Skilled USPSA pistol shooter with a passion for precision and performance under pressure.
– Custom Builder – Enjoys building and tuning firearms and equipment to meet the exact demands of the hunt or the range.
– Experienced Marksman – Experienced in long-range hunting and precision rifles to meet the demands of the terrain of the West.
– Montana-Based Perfusionist – Medical professional accustomed to making critical decisions in high-stakes environments.