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."
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.
The SPIRO is currently available in two mount styles: Direct Thread (DT), and HUB (1.375x24 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.
We have a dedicated 6mm / .243 version of the SPIRO. It is designed for 6ARC, but can also accomodate .243WIN and 6 Creedmoor (see minimum barrel lengths in table, opposite).
The 6MM version meters the following on 6 ARC (16" Geissele AR-15, Hornady TAP)
- Milspec (muzzle) 137.7 dBA; LEQ dBA 124.5
- Shooter's Ear 138.0 dBA; LEQ dBA 125.0.
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.
| Versions | 5.56mm/.223; 6mm/.243 |
| Maximum rated caliber (.223 version) | .223/5.56mm caliber, .22 Creedmoor |
| Maximum rated caliber (.243 version) | .243 Win, 6 Creedmoor |
| Material | Haynes 282 |
| Length | 5.9 inches |
| Length added | 5.3 inches (DT) |
| Diameter | 1.8-inch OD |
| Mounts | Direct Thread 1/2-28 (DT) -- for .223 Direct Thread 5/8-24 (DT) -- for .243 HUB (1.6" from TE to first baffle) * no mount included with HUB version |
| Weight | 15.5 ounces |
| Finish | Black CeraKote |
| Brake Material | Haynes 282 |
| Use | Gas Guns / Hard-Use/Full-Auto |
| Price | $995 |
| Warranty | TBAC Limited Lifetime Warranty |
| How to order a suppressor | |
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.
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.
| "any" | 4.6x30 HK, 5.7 FN |
| 8" | .223, 5.56mm, 5.45 Russian |
| 12.5" | 22 ARC, 224 Valkyrie |
| 18.0" | .22-250, 22 Creedmoor |
| "any" | 4.6x30 HK, 5.7 FN |
| 8" | .223, 5.56mm, 5.45 Russian |
| 12.5" * | 22 ARC, 224 Valkyrie, 6 ARC ** |
| 18.0" * | .22-250, 22 Creedmoor, .243WIN, 6 Creedmoor*, 6GT |
The HUB interface version of this suppressor is meant for advanced users who are familiar with HUB-compatible mounts and know how to use their choice of HUB mounting system in a secure, reliable, and repeatable manner. If you get the HUB version, you should know what you're doing. Everything behind the suppressor body is your responsibility.
We are not responsible for damage caused to this suppressor by another manufacturer's HUB mount system, through its use, misuse, incompatibilities, or any other reason related to the mounting system.
For our part, we will guarantee that the HUB interface is correct and the suppressor will have acceptably-low runout when mounted on a TBAC reference HUB/DT interface.
When using heavy firing schedules, it is imperative that you: properly fix the HUB mount into the suppressor (loctite #272 recommended); use a HUB mounting adapter system that is intrinsicly secure/tight when hot and under heavy firing schedules; and make sure the muzzle device is properly secured to the muzzle threads (loctite #272 recommended).
