SILENCER SATURDAY #248: SIG Sauer MCX Virtus, MCX-Spear LT, and SLX762C-QD Rifle Suppressor

Pete
by Pete
SILENCER SATURDAY #248: SIG Sauer MCX Virtus, MCX-Spear LT, and SLX762QD-C Rifle Suppressor

Good evening everyone and welcome back to TFB’s Silencer Saturday brought to you by Yankee Hill Machine, manufacturer’s of the YHM R9 multi-host suppressor. My apologies for missing last week’s edition; I was traveling on Saturday and was planning on shooting and publishing a review on a new suppressor. Fear not, we’ll get to it next week. I had the pleasure of bringing the SIG MCX-Spear LT, a few SIG suppressors and host of other guns and gear on my travels. This week we get a look at the SIG Sauer SLX762C-QD – a compact rifle suppressor that sits nicely on carbines with long or short barrels. Let’s take a look.

SIG Sauer @ TFB:

SILENCER SATURDAY #248: SIG Sauer MCX Virtus, MCX-Spear LT, and SLX762C-QD Rifle Suppressor

A few years ago I probably would not have suggested a compact or ‘K’ sized rifle suppressor as a first, second, or even third purchase. The thought was that, because short cans are relatively loud, new owners could have their decibel reduction expectations destroyed. There’s just no getting around physics. The ‘K’ referenced above used in some model designations (like MP5K) is an abbreviation of ‘Kurz’ the German word for short. Most of you know that already, but I hate it when people drop a term into a sentence as if I should already understand exactly what it means.

Anyway, back to my point. Today, with technological advancements in materials and suppressor designs, I could easily see suggesting a compact suppressor as an early purchase for a newer shooter. After all, the use case for the host/silencer combination is really the biggest factor in this NFA equation. Whether you looking for maximum suppression for a bench rifle or the smallest form factor for a personal defense weapon (PDW), your suppressor should pair with your host weapon like a fine wine with either chicken or beef. (I have no idea, I’m not a wine guy.)

SILENCER SATURDAY #248: SIG Sauer MCX Virtus, MCX-Spear LT, and SLX762c-QD Rifle Suppressor

Above: The SIG Sauer MCX Virtus in 300BLK with a 6.75″ barrel with the SIG SLX762QD-C suppressor.

I am a huge fan of the SIG MCX family of carbines and their advancements over the standard AR-15 carbines most of us know and love. Not the least of which is that these guns were built to run suppressed. The short stroke piston action, the two-position gas regulator, and hand guards that are mean to be removed easily to provide access to muzzle devices and quick detach systems make the now three generations of MCXs great silencer hosts.

Within the last few years, SIG has discontinued their SRD of tubeless rifle suppressors and replaced them with the SLX and SLH models that are built with additive manufacturing processes. Both models focus on low toxicity for the operator by allowing gas to move forward instead of back out the action, but they each have their own strong points. As a reminder from our previous SIG Sauer suppressor review:

  • SIG SLX Suppressors: Supersonic performance focus, low toxicity, flash reduction.
  • SIG SLH Suppressors: Subsonic performance focus, low toxicity, superior noise reduction.
SILENCER SATURDAY #248: SIG Sauer MCX Virtus, MCX-Spear LT, and SLX762C-QD Rifle Suppressor

Above: The SIG Sauer MCX Virtus in 300BLK with a 6.75″ barrel with the SIG SLX762QD suppressor.

The SLX762 and SLX556 line of suppressors are all made from Inconel which is extremely strong and can withstand extremely high temperatures. The titanium alloys are reserved for some of the SLH762 and SLH300 models. Remember, the SLX family is made for supersonic ammunition and heavier firing schedules. The tradeoff for sustained strength under extreme temperatures is a bit of extra weight. Like most of us after a successful holiday season.

Let’s compare today’s two models.

SIG Sauer SLX762QD-C

SIG Sauer SLX762QD

SILENCER SATURDAY #248: SIG Sauer MCX Virtus, MCX-Spear LT, and SLX762C-QD Rifle Suppressor
SILENCER SATURDAY #248: SIG Sauer MCX Virtus, MCX-Spear LT, and SLX762C-QD Rifle Suppressor

As you can see, the SLX762QD-C saves you 2.2 inches and almost seven ounces over the full sized version, which is fairly considerable. But how does it sound?

SILENCER SATURDAY #248: SIG Sauer MCX Virtus, MCX-Spear LT, and SLX762C-QD Rifle Suppressor

The impetus for this review was the release of the latest generation of MCX rifles – the MCX-Spear LT. The first models to roll off the line had 16″ barrels and the SLX556-QD I had in inventory is also 7.4 inches, making the MCX-Spear LT barrel effectively 23+ inches long and the overall length of the entire platform almost 42 inches long. This new MCX needed a K sized suppressor.

SILENCER SATURDAY #248: SIG Sauer MCX Virtus, MCX-Spear LT, and SLX762C-QD Rifle Suppressor

SIG Sauer MCX-Spear LT – 5.56mm, 16″ barrel

Manufacturer’s Page: https://www.sigsauer.com/mcx-spear-lt.html

  • SKU: RMCX-556N-16B-LT
  • CALIBER: 5.56 NATO
  • BARREL LENGTH: 16 in (406.4 mm)
  • MAGS: (1) 30rd Polymer Mag
  • INCLUDED MAG TYPE: AR-15
  • ACTION TYPE: Semi-Auto
  • STOCK TYPE: Folding
  • BARREL MATERIAL: Carbon Steel
  • TRIGGER TYPE: Flat Blade Match
  • TWIST RATE: 1:7
  • FOREND TYPE: Alloy
  • GRIP TYPE: Polymer
  • RECEIVER FINISH: Coyote
  • OVERALL LENGTH: 34.3 in (870 mm)
  • OVERALL WIDTH: 2.9 in (73.7 mm)
  • HEIGHT: 7.5 in (190.5 mm) without magazine
  • THREADS: 1/2 in – 28 tpi
  • ACCESSORY RAIL: M-LOK
  • OPERATING SYSTEM: Gas Piston
  • WEIGHT: 7.5 lb (3.4 kg)

Even SIG recommends the compact SLX.

SILENCER SATURDAY #248: SIG Sauer MCX Virtus, MCX-Spear LT, and SLX762C-QD Rifle Suppressor
A compact suppressor on barrels 14.5″ and longer are sometimes a better choice than a full size suppressor. Obviously there is a weight and length benefit, but longer barrels allow for a more efficient burn of powder inside the barrel itself, rather than in the suppressor or outside of the muzzle. This means that some hosts may not see a direct correlation in suppressor length and noise reduction when longer barrels are used.
SILENCER SATURDAY #248: SIG Sauer MCX Virtus, MCX-Spear LT, and SLX762C-QD Rifle Suppressor

On the other hand, if you aren’t chasing that mythical decibel dragon and are more concerned with overall weight and length, a shorter rifle suppressor can mean a very compact host. Above, the MCX Virtus in 300BLK with a 6.75″ barrel is a fantastic PDW. Up until recently I had been running the older, but very capable SRD762TI-QD suppressor for both subsonic and supersonic rounds. However, the compact SLX performed very nicely with both types of ammunition. Louder? Sure, but this combination still sounded good and saved about three inches off the front of the gun.

SILENCER SATURDAY #248: SIG Sauer MCX Virtus, MCX-Spear LT, and SLX762C-QD Rifle Suppressor

Like all compact or ‘K’ sized suppressors, the SLX762C-QD won’t take home any whisper-quiet trophies. The tradeoff putting up with a little extra noise is several ounces less hanging off the end of a barrel and a dramatically reduced overall length.

I can’t in good conscience ever recommend shooting any centerfire supersonic rifle round without wearing hearing protection, no matter which suppressor you are using. But, in the name of science, I can tell you that the 16″ MCX-Spear LT is almost pleasant to shoot outdoors with the SLX762C-QD. And I bet you could get the sound down a little more with the SLX556C-QD, the 5.56mm version.

This compact model on the 6.75″ MCX Virtus was fine with subsonic ammo (I’m a snob for quiet 300BLK shooting) and just ok with supersonic ammo. But it is a probably the most compact (and fun) suppressed PDW I own. Highly recommended.

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


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Pete
Pete

Silencers - Science Pete@thefirearmblog.com

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2 of 7 comments
  • Airwolf Airwolf on Oct 16, 2022

    Additive suppressors are a hard sell for me as somebody who is not an FFL. They can't be repaired like a traditional stacked baffle suppressor and if you have a baffle strike, you're up shit creek without a paddle.

  • Garrett sexy slut Garrett sexy slut on Oct 23, 2022

    Looks great

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