Good afternoon everyone and welcome back to another Silencer Saturday brought to you by our friends at Yankee Hill Machine, manufacturers of the impressive little Turbo K 5.56mm suppressor. Last week we did a bit of POI shift testing with three of the most popular rimfire silencers on the market. We’ll get it to more suppressed precision rimfire rifle work with the Vudoo Gun Works V-22 in the weeks ahead. But this week I wanted to touch on the common suppressor under handguard question. Is it a good idea? Let’s take a look.
Function over form has been my motto for decades – one look at my “wardrobe” will prove my point. For the AR-15 platform and its derivatives, running a suppressed carbine is a balance between barrel length, gas system length, overall length and handguard real estate for hand placement and accessories. Let’s break down the issues one by one in order to make a better decision on if running a suppressor under a handguard will work for you and your setup.
Before we begin, there are certain platforms like integrally suppressed rifles and carbines will require tucking a suppressor under a handguard or rail system. Internal volume and barrel porting dictates a long suppressor tube that can reach as far back as the receiver.
SILENCER SATURDAY #143: Suppressor Under Handguard – Should You?
For a short barreled 5.56mm AR-15, the shortest functional/proven/reliable barrel length is 10.3 inches. My personal preference for a short barrel rifle is in 11.5 to 12.5 inches to take advantage of that extra powder burn to push the bullet rather than just creating noise and flash. A typical 5.56mm suppressor has an overall length of six inches, with another two inches added on for a mount and mounting system. The end result is an 18 inch barrel and suppressor combination in the most widely excepted short profile. So if you are looking to reduce barrel length to keep the overall length of your carbine to a minimum, you may want to look for another cartridge.
Enter 300BLK – a round purpose-built for short barrels and suppressors. The shortest accepted barrel length for 300 blackout is right around 5.5 inches. While I fully enjoy the compact PDW nature of the SIG Sauer MCX Rattler, my current preference is for the 6.75 inch barrel MCX Virtus which was built to be suppressed all the time.
With barrel lengths that can be half as short as their 5.56mm kin, 300BLK chambered guns can have overall lengths that are PDW in size. Compact guns that retain their muzzle velocity and energy are a blessing – consider the comparison between a six inch 5.56mm gun and a six in 300BLK gun. One is excels at making fireballs and not producing enough velocity for sufficient terminal performance, the other is 300BLK.
But I digress. My main point is that, because of realistic length limitations, running a suppressor under a handguard makes more sense on a 300BLK gun over a 5.56mm gun. A longer barrel means a longer rail without the need to go over the suppressor.
With all of those considerations in mind, what are the actual pros and cons of running a silencer under a rail system?
- Additional rail area for lights, lasers, BUIS, etc.
- Ergonomics and hand placement options.
- Cool factor level 10
- Can’t run unsuppressed without reconfiguration.
- Heat management – hands and accessories.
- Rails with inner diameters large enough for some suppressors can be hard to find
My use requirements for this particular setup puts handguard area for accessories at the top of the pro list and heat management on at the top of the con list.
Be sure to look for a rail system that has enough clearance between the suppressor, especially for M-LOK setups that may require additional space to attach mounts. You also want enough ventilation cuts to allow for the movement of air. Any rail/handguard that makes contact with the suppressor is probably not a good choice.
The MCX is also unique in that the handguard can be removed by pushing the front pivot pin. So if you need to access your mounting system or remove a direct thread suppressor, the process is quick and painless. I confirm my laser zero after reinstalling, however I’d do the same with a more traditional AR-15 rail mount setup.
Supersonic ammunition will heat up the silencer and rail faster than a running subsonic ammunition, so that may play into your considerations as well. However I have run this particular setup fairly hard with subsonics and the forward section over the silencer gets hot enough to to be uncomfortable.
Here’s my suggestion when it comes to installing a suppressor under a defensive AR-15 or equivalent; for a short barrel setup, if it serves a function or purpose – like added rail space – go for it. For barrels over eight inches long on a defensive carbine, there’s probably no real need fur the additional rail space and you’d be better served at being able to shoot either suppressed or unsuppressed without a dramatic reconfiguration.
For range guns that don’t serve a defensive purpose, a 16 inch barrel, an eight inch suppressor and a 20 inch rail will have all the ladies (or men) honking and waving. However we will still silently judge you.
Have a great week. Be safe and we’ll see you back here for another Silencer Saturday.
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