SILENCER SATURDAY #171: Full Auto Rated Suppressors – Fun And Science!

    SILENCER SATURDAY #171: Full Auto Rated Suppressors - Fun And Science!

    SILENCER SATURDAY #171: Full Auto Rated Suppressors - Fun And Science!

    Good afternoon and welcome back to TFB’s Silencer Saturday brought to you by our friends at Yankee Hill Machine. Full auto rated suppressors have been an industry selling point for years, but those ratings come with their own caveats. The overwhelming majority of suppressors sold to consumers in the U.S. will never see any fully automatic rates of fire, let alone at the brutal SOCOM/MILSTD testing protocols. But, if you own a transferable machine gun, that full auto rated stamp of approval is pretty important. Silencer Saturday is finally ready to offer you a limited amount of select fire observations along with our suppressor reviews. Don’t expect full load out and burn down type displays – my ammo budget is about as long as James’ inseam.

    More Silencer Saturday @ TFB:

    IMPORTANT DISCLAIMER: There are only a few ways to own or use select fire or fully automatic firearms in the United States. First, is to buy and legally transfer machine guns that were manufactured and registered prior to the infamous 1986 cut off date. A second way is to be a licensed manufacturer with a Special Occupational Tax stamp payment – Type 07/02 FFL/SOT. While I believe that we all should have the freedom to own and manufacture whatever we wish, the law is the law. DO NOT ATTEMPT TO MAKE A SELECT FIRE WEAPON WITHOUT THE PROPER ATF APPROVALS.

    I hate that I have to write that, but I don’t want anyone walking themselves into a felony.

    In this episode of TFBTV, James Reeves discusses some tips for suppressing your MP5, more specifically for suppressing the MP5-K PDW (or SP5-K PDW). James reviewed the Heckler & Koch Operator’s Manual, H&K’s MP5 Armorer’s Manual, spoke with H&K engineers and customer service, and even interviewed Federal Law Enforcement who have used a suppressed MP5-K PDW to get a few pointers for TFBTV viewers. At the same time, James used the opportunity to review the brand new OSS RAD-9 suppressor to see how it worked with the SP5-K PDW.


    • 0:00 Intro
    • 2:21 OSS RAD-9 Features
    • 6:10 Is the MP5 Good as a Host Gun?
    • 10:42 Tuning the MP5 for Silencer Use
    • 13:20 Should You Change Your Extractor?
    • 15:53 Impact of Size/Barrel Length
    • 17:05 MP5 vs. MP5-K PDW
    • 17:48​ Sound Test with OSS RAD-9

    ««« GIVEAWAYS »»» PLEASE check out our Patreon and Subscribe Star pages if you enjoy our program, and consider helping us at TFBTV out! We give away hundreds of dollars of gear a month to our supporters!​ or​

    SILENCER SATURDAY #171: Full Auto Rated Suppressors – Fun And Science!

    Before you start looking at silencers for your machine gun (one of the most American statements ever uttered) you are going to want to evaluate your intended hosts. Submachine guns, carbines, and rifles will all behave differently when a suppressor is added to the system. Direct impingement, short stroke piston, long stroke piston, roller delayed, and other actions will add additional complexities. In today’s TFBTV video, James breaks down suppressing the iconic MP5K-PDW. While it’s suppressor-ready right from Germany, the SP5K-PDW and its select fire big brother the MP5K-PDW may benefit from some small upgrades. It’s worth the watch.

    • Direct Impingement AR-15’s:
      • Adjustable gas blocks, gas system lengths, buffer weights, buffer springs, barrel lengths
    • Piston Rifles:
      • Gas adjustment, barrel lengths
    • Roller Delayed Guns:
      • Locking pieces, extractors, barrel lengths

    Considerations For Full Auto Rated Suppressors:

    From the outside, a full auto-rated silencer may not look much different from any other suppressor. But if you truly intend to push as much hot lead through your can (wait, what?), you are going to want to pay close attention to the specifications. Some manufacturers build real-deal full auto ready silencers that can withstand SOCOM/NSWG/MILSTD testing protocols. Other manufacturers build suppressors that can withstand heavy use, but intend on replacing damaged units in the unlikely event they see sustained high rates of fire.

    Internal Volume:

    When sound performance for subsonic rounds is a priority, internal volume of the suppressor is one of the most important factors to consider. With slower rates of fire, the host/silencer system can handle the pressure changes between shots. Under high rates of fire, the host/silencer system can get overwhelmed and performance can suffer. Large diameter and longer suppressors increases the internal volume, allowing for more room to handle lots of gas. An alternative can be flow-through type suppressor systems that can vent pressure out the front instead of back into the action.

    SURG Testing – Crane 2017

    Cyclic Rates/Blowback:

    Directly related to internal geometries and volume, good full auto rated suppressors should be able to keep blowback to a minimum. Increasing cyclic rates can effect overall reliability and the lifespan of certain  wear parts.

    SURG Testing – Crane 2017

    Durability/Heat Mitigation:

    Suppressors get very hot, very fast. Under full auto fire, everything gets even hotter, even faster. A proper full auto rated suppressor will be constructed with high strength steel alloys.

    SURG Testing – Crane 2017

    Full Auto Rated Suppressors – MP5K-PDW

    I’m not a video guy – I leave this stuff to the experts like James. But this is hopefully the first of many short comparison clips that will find their way into Silencer Saturday reviews.

    Finally, let’s shoot some select fire guns. First up, let’s compare the big GSL Phoenix to the compact YHM R9. Surprisingly, the tiny R9 was just slightly louder than the Phoenix with all its internal volume. For a K-Sized subgun can with a street price below $500, the YHM R9 really holds its own. And yes, I’d say that even if YHM didn’t sponsor our weekly gatherings.

    SILENCER SATURDAY #171: Full Auto Rated Suppressors - Fun And Science!

    SILENCER SATURDAY #171: Full Auto Rated Suppressors – Fun And Science!

    Full Auto Rated Suppressors – AR-15/M-16

    I had hopes of comparing a few 5.56mm suppressors today, but I quickly realized that I don’t have a suitable upper platform for suppressed full auto fire. I adjusted my gas block (only three positions) and swapped out buffer weights but found out that I need a different configuration that will work reliably across a host of different cans.

    It did demonstrate how different silencer designs effect host weapons in different ways. The YHM Turbo K ran with only one gas adjustment, whereas the CGS Helios QD with the flow through end cap basically had zero back pressure and I didn’t have a stock AR-15 setup available that would properly cycle. This isn’t a knock on either YHM or CGS, they just have different designs.

    SILENCER SATURDAY #171: Full Auto Rated Suppressors - Fun And Science!

    SILENCER SATURDAY #171: Full Auto Rated Suppressors – Fun And Science!

    I’ll refine my AR-15 testing platform and bring you more videos in the weeks ahead.

    Have a great week, be safe and we’ll see you back here next weekend for another Silencer Saturday.

    Silencer Saturday is Sponsored by Yankee Hill Machine

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    DEALERS: If you want your link to buy YHM suppressors included in future Silencer Saturday posts, email: [email protected]


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