Spiro Suppressor

Low Back Pressure Gas Gun Suppressor
Extreme Duty/Full-Auto
Dedicated versions for 5.56mm; 6mm (6ARC)

The SPIRO is a low back pressure gas-gun suppressor that has excellent sound suppression levels at both the muzzle and at shooter’s ear.

No longer do you have to compromise and have your gas gun suppressor be “Low back pressure but loud at the muzzle.”

5.56 SPIRO – SPIRO OVERVIEW

The 5.56 SPIRO increases back pressure gas flow by only approximately 50% compared to a bare muzzle (most LBP are 35-85%), which is 3X less gas than a Dominus-SR. The SPIRO only increases the cyclic rate of an Mk18 by about 5% (compared to 43% for a Dominus-SR; most LBP 3%-10%). This is while keeping Shooter’s Ear peak dBA at 136.8 (LEq dBA 124.2), and milspec-left muzzle position 135.4 dBA (LEq dBA 122.5). For reference, the Dominus is a few dB louder at the milspec position and at the shooter’s ear. In addition, the SPIRO reduces recoil by approximately 40% compared to a bare muzzle.

SPIRO COMPARATIVE PERFORMANCE DATA TABLE

From the table, the SPIRO eclipses popular “low back pressure” suppressors in terms of muzzle and shooter’s ear suppression levels, when considered together. It does this while only adding approximately 5.3″ to the overall weapon length.

It is a “Go To War” suppressor designed for 10.5″, 5.56mm caliber assault rifles. It works great on .223 / 5.56mm caliber gas guns from 8″ up to 16″ or longer. The SPIRO is designed to be put on your 5.56mm carbine and shot a lot, only being removed for firearm maintenance and suppressor cleaning.

The SPIRO is made from Haynes 282, a nickel-chromium-cobalt-molybdenum “Super Alloy.” It is stronger than Inconel 718 and exceeds Inconel’s operating temperatures by about 500 degrees F. This makes the SPIRO almost indestructible. While our other “full auto rated” suppressors are guaranteed to last 10 cycles of the 8-mag SOCOM SURG test on a 10.5″ barrel, the SPIRO is rated for over 20 of the same cycles using an 8″ barrel instead of a 10.5″.

People have been talking about “low back pressure” for a while, but there hasn’t been an objective method to actually quantify it. We weren’t satisfied with that, so we invented the TBAC Method of Measuring Back Pressure, and then we used the same sound-test setup we use at the SILENCER SUMMIT to make a very low-back-pressure suppressor that is also unbelievably quiet at both the muzzle and at the shooter’s ear, for a suppressor under 6″.

BACK PRESSURE MEASUREMENT VIA TBAC METHOD

We tested all the supposed low back pressure cans on the market, as well as the conventional high pressure cans. The SPIRO is the result of over two years of TBAC R&D and it delivers on these design goals:

1. Back pressure as low as anything else on the market,
2. Muzzle suppression to meet or exceed a Dominus,
3. Full-auto+ firing schedule,
4. Less than 6″ OAL added to weapon.,/li>

The SPIRO is currently available in two mount styles: Direct Thread (DT), and HUB (1.375×24 tpi standard, aka “Bravo”). DT is recommended for dedicated gas guns, where the intent is that the gun always has the suppressor mounted. In this case, retention is provided by using the included Nord-Lock washer. HUB is offered for user flexibility and users who are familiar with their own preferred mounting system. For the HUB version, the Thread End (TE) to First Baffle (TETFB) distance is 1.6″.

The SPIRO is subject to one or more US patents pending.

SUPPRESSOR DURABILITY RATINGS

There is general confusion as to what firing schedules different suppressors on the market can actually withstand. We’ve seen “full auto”-rated suppressors that will fall apart after a few mags of full auto, and on the other hand, there are some “precision rifle suppressors” that will actually withstand a lot of abuse.

We rate our suppressors conservatively and try to be as accurate as possible in our description of what use they can withstand “forever” or for their defined service life. To this end, we have defined the following firing-schedule categories for our centerfire rifle suppressors.

SPIRO CATEGORY: “HARD-USE/FULL-AUTO MOD 1” [HU/FA/1]

Lifetime to exceed at least 20 SURG cycles on a 8.0″ “Mk18 Style AR”.
Note that the upper and muzzle devices will likely not survive this entire trial.

One SOCOM/SURG CYCLE comprises
Mag 1: 1 round/second
Mag 2: 2 rounds/second
Mag 3: 1 round/second
Mag 4: 3-5 round burst
Mag 5: 1 round/second
Mag 6: 2 rounds/second
Mag 7: 1 round/second
Mag 8: 1 continuous burst
Outlined in Section 3.6.1.i. in Solicitation H92222-17-R-0011

The basis for this is the SOCOM/SURG specification, which is a common heavy firing schedule specified in many military solicitations. One SURG cycle is 8 magazines (30 round magazines) fired in this pattern, with magazine changes happening as quickly as possible. After a full 8-magazine cycle, the suppressor and firearm is allowed to cool to ambient. This firing schedule significantly exceeds the worst-case application of assault rifles and battle rifles. A milspec M4 needs service and inspection after each cycle to keep operating.

Suppressors in this category will still have minimum barrel length ratings for most cartridges.

MINIMIM BARREL LENGTHS FOR SPIRO 5.56

MINIMIM BARREL LENGTHS FOR SPIRO 6MM/.243

* Note that these are the barrel ratings at maximum operating temperature. The suppressor “may” be able to be used a shorter barrel lengths on these cartridges if the temperature is controlled. Please inquire if you have a specific application and need guidance.

** This barrel rating for 6 ARC is also valid for “High Pressure” 6 ARC (80kpsi) variants that are in development.

SPIRO Q&A’s

Your other cans are known for accuracy– is the SPIRO accurate?
Yes, the SPIRO will deliver the same accuracy you expect from TBAC when shot on accurate carbines or bolt guns.

This is for .223 and .243/6mm cal — where’s the 6.5mm / .30 cal version?
The SPIRO was first introduced in 5.56mm caliber, and then 6mm/.243. The line will be expanded to cover additional “Gas Gun” calibers and cartridges in roughly the order of their popularity or importance.

Are DT and HUB the only mounting options?
We plan to introduce an SR-style version in the near future.

What does ‘SPIRO’ mean?
SPIRO in Latin means, “To Breathe.”

How is “Spiro” pronounced?
It is pronounced “SPEAR OH”, like the SPIR in “Aspirate”.

Is the HUB version of this also full auto rated?
Kind of. The suppressor is rated for it, if your mounting system will stay tight and keep the can straight. For HUB versions, that’s on you. We know DT with Nord-Lock washers will stay tight, and we know that SR will stay tight.

HUB INTERFACE DISCLAIMER