May 17, 2020
By David Fortier
LaRue Tactical has become synonymous with quality and innovation and is a well-recognized name today in the firearms world. It’s interesting to note though that this company’s background is not firearms related. It was actually founded in 1980 by Mark LaRue as Austin Precision Products, Inc. In its early days this “Dead Center of Texas” based company was dedicated to servicing the Semi-Conductor Industry. It accomplished this via its ability to manufacture highly complex products to exacting tolerances. However, fate was to lead the company to greater things.
One military unit, duly impressed by a resetting target system he designed simply to shoot during his lunch break, contacted him shortly after the War on Terror was launched in earnest. Their question was simple, would he be willing to design and manufacture optic mounts specifically for their needs. Although this was far outside the scope of work Austin Precision normally undertook, Mark readily agreed. Despite the fact that he would likely never recoup his design and manufacturing costs, Mark wanted to do his part to help the military. So he put his team to work. In an incredibly short amount of time they had not only designed a rugged QD mount with a proprietary attaching system, but he had samples in the hands of troops. User feedback led to a complete redesign to strengthen and improve it. The end result was that in an amazingly brief amount of time a scope mount for the M4 carbine went from concept through at least 4 generations, to mass production. It is now fielded in combat operations both in Afghanistan and Iraq.
The willingness of LaRue to respond to their specific needs, his creativity, his speed and the quality of his shop's work led this group to request more items. Other units in the field soon took notice of the LaRue mount as well, and made requests of their own. The result was the birth of the LaRue Tactical division of Austin Precision. From that one M4 scope mount LaRue has developed a diverse array of military grade products for the AR, and other platforms.
It’s interesting to note the majority of LaRue’s products were developed specifically at the request of, and with input provided by, real world end users. It is the same for their TranQuilo sound suppressor. During an interview for this article Mark LaRue stated, “My TranQuilo was made by request after a small crowd of active SF guys cornered me at our Vegas SHOT Show Demo Day, three or so years ago. They implored me to make a low or no back-pressure suppressor saying the guys were coming down with a variety of health issues and some schools of thought blamed over-exposure to gun smoke fumes inhaled when high back-pressure suppressors blast the shooter with back-blast, back-blasts that occur when high back-pressure cans are still under pressure at the time of the extraction and ejection.”
Typically when riflemen talk of back-pressure it’s in the context of shooter comfort, regarding how much gas is blown back towards the shooter’s face. Back-pressure is something suppressed shooters have to deal with, more-so with auto-loading rifles where the shooter’s face is in close proximity to the firearm’s action. Gas, both in front of and behind the projectile, is trapped and redirected on a suppressed firearm. How much back-pressure is generated depends upon the design of the suppressor and the host weapon itself. I’ve used some designs, which when mounted onto an M4 carbine exhibited back-pressure severe enough the resultant gas cloud made it difficult to breathe and burned the eyes. Inhaling these contaminants is not healthy, similar to why you should thoroughly wash your hands after shooting before you eat.
Back-pressure can also raise the cyclic rate of a firearm. This can effect operation and shorten the firearm’s service life. Excessive back-pressure can lead to rapid fouling (affecting accuracy) and additional heat transfer to the firearm. Both of these will adversely affect reliability. Back-pressure can also affect the perceived or measured noise reduction of a suppressor.
In response to this request Mark LaRue set out to develop a suitable sound suppressor. He had on an idea on how he thought it should function but needed a way to measure the back-pressure generated when fired on a rifle. So he designed and built a device to accurately measure back-pressure. With this accomplished he could test and compare his suppressor concept. LaRue’s idea was to redirect the gas which would normally escape out of the rear of the suppressor and vent it out the front.
The result of his work is the LaRue Tactical TranQuilo sound suppressor. The TranQuilo is a .30 caliber suppressor specifically designed for the Larue family of semi-automatic precision rifles. It reduces the report to hearing safe levels and almost eliminates flash. The key to its operation is what LaRue calls Safer Operator Technology or SOT. This patented system is designed to reduce gas blow-back emitted from the ejection port. LaRue manufactures the TranQuilo from 17-4 PH Stainless Steel and Incoloy A-286. It measures eight inches in length and weighs 23 ounces. Handling it you’ll note it features a collet mounting system, raised ribs for a secure grip when installing/removing and protrusions at the front to help disperse any flash. You’ll also note a ring of small holes at its front. These are important.
All the magic is sealed up out of sight inside the suppressor. So, I asked Mark LaRue about his design. He replied, “We achieved our extremely low back-pressure (taken at the time of extraction) by exhausting captured gas pressure from both ends of the suppressor, out the front. There is a pathway between the tube on the outside of the baffles for the rear gas to travel to the front. The ring of holes let the gas escaping from the rear of the can escape out the front. And the air escaping the can from the rear dumps the barrel pressure at its closest to dump point.”
While we were talking I commented that it seems like it would be expensive and complicated to manufacture. “Not a weld in it makes it relatively easy,” was his reply. So he designed the TranQuilo with an eye towards mass production with no welding required. When I asked him what he likes best about the design he replied, “It kills the back-pressure, preserving accuracy by prolonging the plating of the chamber with crud, which jacks with headspacing.”
LaRue developed a proprietary mounting system for the TranQuilo. The suppressor mounts onto LaRue Tactical’s TranQuilo muzzle brake/sound suppressor adapter. This unit acts as a conventional muzzle brake to reduce felt recoil and muzzle movement. In addition it also acts as a mounting adapter for LaRue Tactical’s TranQuilo sound suppressor. A three baffle design, it features multiple round ports on the top, external threads and an angled shoulder behind the threads which acts as an indexing point. To mount the suppressor you merely place the device onto the mount, thread it on hand tight and tighten the collet locking ring down. While not as fast to mount/dismount as some designs, it’s pretty straightforward. When I asked Mark about his attachment system he replied, “You can shoot 1,000 rounds and it still comes off easily, without the need of a hammer, two men and a boy.”
The LaRue TranQuilo utilized for this article was not a review item but out of my personal collection. I originally acquired it for use on my LaRue PredatOBR rifle in .260 Remington. This has seen moderate use shooting paper at 100 yards and steel from 200 to 800 yards. With the TranQuilo mounted the rifle is very pleasant to fire. Sound reduction is impressive, recoil is reduced and accuracy is measurably enhanced. To demonstrate the effect on the rifle I fired three five-shot groups without the suppressor and with the suppressor from the bench at 100 yards. Test ammunition was Black Hills’ 140-grain ELD Match. You can plainly see from the photos of the test targets how the addition of the TranQuilo reduced group sized and note the slight POI change. Average group size unsuppressed was .7 inch while suppressed was .5 inch. There was a .5 inch difference in POI between them. Accuracy at 800 yards with this load using the TranQuilo averages 4.7 inches.
But how does it perform with other brands of rifles, action types and calibers? I specifically acquired the .30-caliber TranQuilo with the intent to use it on a variety of rifles in a variety of calibers. To date it has been used with 5.56x45mm NATO, .22 Nosler, .224 Valkyrie, .25-08, 6.5mm Grendel, 6.5mm Creedmoor, .260 Remington, 300 AAC Blackout, 7.62x39mm and 7.62x51mm NATO. It has provided comfortable shooting with excellent noise reduction in all cases except two. Shooting subsonic 300 AAC Blackout and subsonic 7.62x39mm I found the performance to be lackluster and the report louder than I was comfortable with without hearing protection. Supersonic ammunition from these two calibers was a different story. So I do not recommend the TranQuilo for use with these applications. But, neither was it designed with these in mind.
I mounted the TranQuilo onto a wide variety of rifles, including bolt-actions and semi-automatics. Barrel length ranged from 11.5 to 24 inches. In a few cases accuracy remained unchanged but typically average group size was measurably reduced. In no cases did accuracy deteriorate. Point of impact change was 1 inch or less and consistent. No problems of any kind were encountered. In no cases was back-pressure or blowback an issue, even during rapid fire. It’s not something I even think about, so evidently LaRue’s design does work as intended.
The TranQuilo is a sealed unit, so there are no user replaceable parts. For maintenance all that is required is an occasional cleaning. LaRue recommends an ultrasonic cleaner. However, if you do not have one he stated running it through a dishwasher also works. I typically smear a dab of Never-Seez onto the mount’s threads. I’ve never had an issue removing the TranQuilo using nothing more than a firm grip.
All in all I am pleased with LaRue’s TranQuilo after not quite two years of use. It spends its days being swapped from one rifle to another, depending upon my mood. It sees frequent use with my 5.56x45mm ARs and quite a bit of 6.5mm Grendel. Its home though remains on my LaRue .260 Rem. This has an 18 inch barrel so the TranQuilo doesn’t make it overly long. I like the uptick in accuracy and how pleasant shooting becomes. If you’re interested in a LaRue TranQuilo the MSRP is $699.
Black Hills Ammunition
LaRue TranQuilo Specifications
- Caliber: .308 Winchester/7.62x51mm NATO
- Material: 17-4 PH Stainless Steel and Incoloy A-286
- Mounting System: Collet with matching muzzle device
- Length: 8 inches
- Weight: 23 ounces
- Sealed: Yes
- Notes: Designed to reduce back-pressure by venting gas from the rear of the suppressor out the front.
- MSRP: $699