AMTAC CQBm Suppressor Review – AMTAC Silencer Review

AMTAC CQBm Suppressor Review – AMTAC Silencer Review The shorty in the AMTAC product lineup of over-barrel silencers, the CQBm fits where longer over the barrel cans won’t. Quick overview […]

AMTAC CQBm Suppressor Review – AMTAC Silencer Review

The shorty in the AMTAC product lineup of over-barrel silencers, the CQBm fits where longer over the barrel cans won’t.

Quick overview for the impatient

  • AMTAC suppressors 762 CQBm silencer review - installedThe AMTAC CQBm is an over-barrel suppressor that extends 4″ aft of the muzzle and 3.7″ forward of the muzzle
  • We tested the .30 cal version of the silencer, the 762 CQBm
  • Sound suppression is better than some .30 cal cans I have shot, but on the modest side at 17-22dB, making subsonic 300 BLK hearing safe
  • The long initial blast chamber helps to reduce back pressure, reducing blow-back into the shooter’s face
  • The 762 CQBm fits over barrels up to .76″ in outer diameter and it fits inside handguards with an internal diameter of 1.62″ or greater
  • For what it is, I really like this suppressor. It is not designed to be the quietest can on the market. Rather, the over-barrel design keeps the overall length of the weapon down compared to typical silencers. To me, this is an ideal can for a SBR with a 10″.
  • Build quality is outstanding with no concentricity or fit & finish issues.

Why length matters

AMTAC Suppressors improved on one of the most annoying problems with silencers… screwing a can onto the end of your barrel adds length to the firearm. With AMTAC’s over-barrel suppressor design part of the silencer extends aft over the barrel. So, only 3.7 inches of this 7.7″ suppressor sticks out past the muzzle. AMTAC calls this an “over-barrel” design. It seems that folks in Europe and elsewhere like to call this a Reflex Suppressor or Reflex Silencer.

AMTAC suppressor 762CQBm review - over barrel silencer beside barrel

How far the 762 CQBm slides over the barrel

762 CQBm above the 762 CQB clear demo can with baffles visible

AMTAC suppressor 762CQBm review - TC Compass with normal silencer

TC Compass rifle with normal silencer

Who cares if a can makes your rifle longer?

I do. And you probably should too. If you wish to avoid the hassles and expenses of a Short Barreled Rifle (SBR), then you are likely rocking a 16.25″ or longer barrel on your rifle. Add a typical 8″ suppressor to the end of the barrel and you now have a rather long lever arm with a pound or more of mass screwed to it. The typical AR with a silencer attached is too long to fit in some cases or gun racks as well. So, you have to take the can off for transport and put it back on before you shoot. That is a PITA and creates opportunities to lose things (for me, at least).  I love that I can secure an AR15 with a full 16.25″ barrel and the AMTAC 762 CQBm attached in the Blac-Rac secure gun rack in the Project HMMWV Battlewagon and it doesn’t poke through the roof.

AMTAC suppressors 762 CQBm silencer review - AR15 in Blac-Rac in HMMWV

You want fries with that?

How much of a difference does it make sliding a normal silencer forward a few inches from where the over-barrel AMTAC suppressor sits? About the same as putting a McDonald’s® Quarter Pounder® with cheese on the end of your barrel. If you are interested in the calculations supporting this, scroll down to the bottom of the review. Unfortunately, there is math involved. You have been warned.

Baffling internal design

One of the things that first caught my attention with AMTAC suppressors is their unique baffle design. They machine each baffle stack out of one piece of piece of stainless steel, which isn’t that unique. There are lots of monocore silencers on the market. However, I don’t recall seeing any other designs that are made like this, with one piece of steel turned down to make the series of baffles. Because the baffles are machined in one step and they also cut the bore and attachment threads in the same machining operation, the typical concerns about baffles lining up properly to avoid baffle strikes are largely negated. Additionally, since this is an over-barrel can, then barrel inside over half of the can’s length is less likely to be knocked off center if dropped or otherwise impacted. Contact with the barrel at the aft end of the suppressor would limit how much the can could be knocked out of alignment unless there were significant damage causing deformation in the body any baffle section.

AMTAC suppressors 762 CQBm silencer review - baffles

Dreaded blowback

Another interesting difference in the over-barrel design of the CQB, CQBm, and Sniper cans from AMTAC is the long initial blast chamber. A high volume blast chamber serves to give the highest pressure initial blast of hot gasses a place to go so they can slow down before exiting. Gases entering the blast chamber have to change direction and move aft 4 inches in the CQBm, farther in the other models, giving ample deceleration space. This lets the pressure in barrel to bleed off quickly so that less pressure is available to blast hot burning propellant residue out the chamber, around the charging handle and into the shooter’s face when the bolt unlocks and retracts. This is especially helpful in guns with pistol and carbine length gas systems, as the bolt opens earlier and often with more force than in guns with longer gas systems.
*Pictured here with at Cole-Tac silencer cover.

AMTAC suppressors 762 CQBm silencer review - end

How quiet is it?

Good question. We are working with a nearby University to develop a silencer testing protocol that does NOT require $15,000 in test equipment and $30,000 in software to do accurately. Rather than wait for that protocol to be completed, we are publishing this review now with no sound suppression measurement data. When the protocol is completed and validated, then we will run all of the silencers in our inventory through the tests and will share those measurements. As of publication date in early November, the assigned researcher has completed his first draft and submitted it to the Physics department Head for review. Once we have the PhD in charge’s sign off we will start field testing to validate the protocol.

In the meantime, AMTAC’s reported dB reduction range is listed below and I can tell you that with 220gr subsonic 300 BLK rounds it “sounded” hearing safe. Not so with supersonic 300 BLK or .223 Remington, which both “sounded” louder than hearing safe. I know… “sounded”… not scientific at all.

How AMTAC describes the 762 CQBm suppressor

CQBm 7.62 Suppressor – MSRP $975.00

  • Over-Barrel Design
  • Single-Piece Machined Baffle
  • For Carbine-Length Gas Systems
  • Reduced Gas Blowback
  • Minimal POI Shift
AMTAC CQBm silencer review - aft end

looking down the sleeve that sits over the barrel

The AMTAC CQBm 7.62 is available in three colors: black , FDE or grey.

Description

The CQBm features a single-piece baffle built with aerospace-grade CNC technology. The unique design adds only 3.7″ to the rifle’s length for better maneuverability. Compatible with a mid-length gas system on a 16″ barrel, this suppressor features direct-thread attachment and can fit under most full-length free float tubes.

AMTAC CQBm silencer review - gasses exiting can

check out the gasses exiting the suppressor

Length: 7.7″

Over-Barrrel Length: 4″

Diameter: 1.62″

Weight: 17.7oz

Thread: 5/8 x 24

Max Barrel Diameter: .76″

Suppression: 17-22dB

AMTAC 762 CQBm silencer compatibility

Barrel Diameter & Clearance   Ø.760”, 4″ muzzle to gas block

Caliber   762 series (CQB-762, SNIPER-762, etc): .243 Winchester through .300 Win Mag

Barrel Thread Pitch 762 series  5/8 x 24 *A 1/2-28 to 5/8-24 thread adapter can be used to mount a 762 series suppressor on a 5.56mm rifle.

Gas System vs Barrel Length CQBm:

  • 20” barrel / rifle-length gas system
  • 16” barrel / mid-length gas system
  • 14” barrel / carbine-length gas system
  • 10.5″ barrel / pistol-length gas system

Wait one moment!

Let’s find out! The further from your shoulder the weight of the silencer is, the more torque gravity exerts on the silencer. To the monkey pulling the trigger that torque feels like additional weight. The AMTAC 762 CQBm slides over the barrel about 4 inches. How much difference does 4 inches make? We can calculate using the formula Weight x Arm (distance from fulcrum to center of mass) = Moment of force (W x A = M). We used the “WAM” formula a LOT when I was a US Air Force Loadmaster, and then later as a search and rescue pilot, to calculate the balance point of the aircraft and make sure it was safe to fly… not too nose or tail heavy.

I put the AMTAC 762 CQBm suppressor on one of our test AR15 rifles with a 16″ barrel and adjustable stock, then measured the distance from the buttstock to the exit end of the silencer. Then I measured the distance from the buttstock to the end of the muzzle. And finally from the buttstock to the exit end of another silencer of the same length. Here are the measurements:

All data in inches AMTAC 762CQBm Normal can
Silencer length 7.7 7.7
Mid point 3.85 3.85
Length shoulder to muzzle 38.75 43.25
Length to balance point = Arm 34.9 39.4

Here are the calculations:

Weight (oz) Arm (in) Moment % change
AMTAC 762CQBm 17.7 34.9 1218.0
Normal can 17.7 39.4 1552.4 27.45%
Perceived weight difference (oz) 4.9

AMTAC CQBm silencer review - perceived weight savings

What does this mean?

Even though the two silencers weigh the exact same amount and are the same length, the AMTAC 762 CQBm feels about 27% lighter. That equates to about 5 oz difference. 1 pound = 16 ounces. So, the normal silencer feels more than a quarter of a pound heavier. That is like walking around with a Quarter Pounder with Cheese sitting on the end of your barrel.

Gears rating

Gear Score
Gearswww.dyerware.comwww.dyerware.comwww.dyerware.comwww.dyerware.comwww.dyerware.com
The AMTAC CQBm is built to provide suppression with minimal additional length added to the rifle. The unique baffle design and long blast chamber reduce blowback and POI shift. This specific model may not be for everyone, as longer models provide more noise reduction. But for those looking for these features it is hard to beat.

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 Suggestions?

Please leave a comment if you have suggestions on other silencers we should consider reviewing, please let us know in the comments.

Ammo for testing provided by

Without the support of our ammo suppliers we would not be able to do nearly the amount of gun reviews that we do today.

Defender Ammunition CompanyDefender Ammunition Company

Big thanks go to our primary Ammo Sponsor Defender Ammunition Company for supplying ammo for our tests and reviews on an ongoing basis. Defender provided a variety of calibers and types of ammo for this test. Gear-Report.com is a proud member of Team Defender

Sig Sauer

SIG provided a wide range of subsonic and supersonic .223 and .300 BLK ammo for this test.

Gorilla Ammunition

Gorilla Ammo provided reman and factory .223, subsonic and supersonic .300 BLK ammo rifle rounds for this test.

 If you like this, you might like our Slide Fire stock review

Where to buy Silencers?

You can legally purchase silencers online and have them shipped to your local SOT FFL, who will help you with the ATF Form 4 transfer process. Here are some links to trusted retailers who sell suppressors.

Quarter Horse Arms - machine gun from HMMWV

Jeff shooting the Quarter Horse Arms AR15 Full Auto from the Project Humvee Battlewagon

The Project Humvee Battlewagon

Gear Report acquired a real HMMWV (High Mobility Multi Wheeled Vehicle) from the US Army for use as our official field and shooting range vehicle. We have already posted about some of our upgrade projects (Project Humvee Battlewagon article links) and have a lot of really cool projects on the way. Consider subscribing so you don’t miss any of the cool reviews as we post them.

Here is our Project Intro (link) and our list of HMMWV upgrade projects.

About Jeff

Jeff is the Editor in Chief of Gear Report and a National Shooting Sports Foundation Media member. He reports on the outdoor industry, reviews gear for camping, hiking, shooting, hunting, paddling, backpacking and other active pursuits.

A USAF veteran, Jeff earned a MBA in Marketing and Health Services. He specializes in consultative selling and internet marketing. As the VP of BD & Marketing, Jeff provides sales and marketing leadership to MGECOM, Inc. and helps http://MGECOM.com acquire new clients in need of solutions for online merchants in need of Affiliate Marketing program management.

Jeff founded and manages Cress Sales & Marketing LLC, offering online sales and marketing consulting and services to online merchants and service providers.