Good afternoon everyone and welcome back to TFB’s Silencer Saturday brought to you by Yankee Hill Machine, manufacturers of the new YHM R45 Multi-Host Suppressor. Last week we paused briefly for the Thanksgiving holiday weekend. This week we get to spend some time with the KAC QDC MCQ-PRT ultra compact 5.56mm suppressor. Can a 4″ silencer perform well enough to justify an NFA purchase? Let’s take a look.

More KAC @ TFB:

• SILENCER SATURDAY #236: Knight’s Armament 556 QDC CQB – Full Auto KAC SR-15
• SILENCER SATURDAY #235: The Knight’s Armament KAC 762 QDC
• SILENCER SATURDAY #233: Full Auto with the Legendary KAC NT4 – USMC Suppressor
• SILENCER SATURDAY #232: KAC Mounts – KAC QDSS and KAC QDC

SILENCER SATURDAY #306: The KAC QDC MCQ-PRT Ultra Compact 5.56mm Suppressor

I have to admit, I have a thing for ultra-compact rifle suppressors. As we we have discussed time and time again, supersonic centerfire cartridges will never been truly hearing safe. A well designed full length rifle suppressor on a barrel longer than 11.5″  will reduce the sound signature well enough to make shooting a more pleasant experience. It can also prevent devastating hearing damage in the event you need to take a shot without hearing protection or in a confined space like a vehicle or hallway. A properly engineered rifle suppressor will also help mask the location of your shots by the enemy.

But if you are looking for anything close to whisper quiet, subsonic rounds and a full-size suppressor are the only rifle platforms that will do the trick.

Besides compact cans, I will also admit to being drawn to KAC suppressors – there is a plethora of design history and product evolution driven by military requirements. As I mentioned last week, the KAC NT4 is one of the most fielded suppressors in history and is currently issued USMC gear. KAC suppressors are also fairly rare in the civilian world and I enjoy shooting and reviewing unique gear.

The KAC QDC/MCQ-PRT is the latest generation of quick disconnect rifle suppressors from Knight’s Armament. While the previous generation of QDC silencers were traditionally manufactured, the latest versions utilize direct metal laser sintering (additive manufacturing). In addition, the new QDC models feature Pressure Reduction Technology (PRT) to vent gases forward instead of back down into the gas system or barrel. As we have discussed in the past, reducing the pressure inside the suppressor keeps cyclic rates at normal levels, diverts toxic fumes away from the shooters face, and optimizes sound reduction.

The KAC QDC/MCQ-PRT or ‘Mini Close Quarters’ ultra compact 5.56 rifle suppressor measures at just over four inches long and adds less than 2.5″ of length to a barrel using the QDC flash hider mount. In comparison, there are muzzle brakes and blast diverters that are longer than the MCQ suppressor. Built with Inconel and made to withstand any barrel length and punishing rates of fire, the weight is just under 14 ounces.

Here’s a size comparison with the Surefire RC2 Mini.

As the name suggests, the KAC QDC/MCQ-PRT uses the QDC line of mounts, which for the 5.56mm is the three prong ‘no ping’ flash hider. As we discussed last year in the KAC mount overview, I do think the QDC is system is one of the best suppressor mounting systems currently available. It looks complex, but is  actually beautifully simplistic and locks up solidly. Unfortunately, most of the world doesn’t know about the QDC system because it is only available on KAC suppressors. If the technology were licensed as a universal mounting system I do think more people would appreciate the one-hand mounting and tight, repeatable lockup.

Stating the blatantly obvious, the KAC QDC/MCQ-PRT is a tiny suppressor. Peeking down the bore I can make out five baffle cones. The muzzle end of the MCQ features a three-pronged flash reducer shape and the slits around the circumference for the PRT gas venting. I did shoot it at dusk one night with an observer and the flash reduction was impressive.

I purchased my MCQ from Freedom Trading Company at the advertised retail price of $1650.

Let’s take a look at the numbers.

KAC QDC/MCQ-PRT – Specifications

• Model: KAC QDC/MQT-PRT
• Manufacturer’s Page: https://www.knightarmco.com/28963/shop/signature-reduction/rifle-suppressors/5-56mm/5-56mm-qdc-mcq-prt
• MSRP: $1650
• Length – Addition to Bare Muzzle: 3.85″ (9.78cm)
• Length – Addition to QDC 3-prong FH: 2.33″ (5.92cm)
• Overall Length: 4.43″ (11.25cm)
• Weight: 13.9oz (395g)
• Sound Reduction: 12dB

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Barrel length is going to be the most important decision when running a suppressor as small as the MCQ. My advice is to stick to a minimum 14.5″ or 16″ to take advantage of the additional powder burn that will take place inside the barrel instead of inside the body of the suppressor. I did shoot the MCQ on the 11.5″ carbine and it was difficult to discern a difference between suppressed and unsuppressed fire. My favorite 14.5″ mid-hybrid gas KAC rifle paired well with the MCQ and had a nice balance.

Still, Knight’s Armament isn’t lying when they list a 12 dB sound reduction in the specifications – I could see the suppressed numbers ending up in the mid 140’s. Physics is uncompromising mistress; a small containment vessel does not leave much room to slow expanding gasses. But if there is need to take shots in confined spaces, 145 dB is a welcome choice to 160+ dB any day of the week. Especially when it means navigating tight corners and doorways easier than with a full size suppressor.

All of this is to say, the MCQ probably wasn’t designed for you. KAC manufacturers true military gear that answers a specific need or request. But that’s not to say people like us can’t find a good use for a tiny suppressor, especially when it is built for supersonic rounds. I will say it is noticeably louder than the QDC CQB I reviewed last year. But the CQB is also ore than an inch longer than the MCQ.

For KAC gear, the price is actually decent. But if you are considering purchasing something from Knight’s, you have already factored the cost into your overall budget. For planning purposes, it does not come with a QDC flash hider and they can sometimes be hard to source. Speaking of hard to source, there is a heat shroud for the MCQ that I have been looking out for – I’ve included the KAC informational video at the bottom of the review.

If you calibrate your expectations correctly, the MCQ can find a place in your armory. As long as you value length (maneuverability) and flash reduction over sound suppression, you won’t be disappointed.

Thanks for reading. Be safe, have fun, and we’ll see you back here next weekend for another Silencer Saturday.

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