YHM ULTimate AR15 Upper Review – Subsonic 300BLK Metering

    YHM ULTimate

    Hot off the heels of double Yankee Hill Machine silencer reviews this past Saturday, we are right back at you today with some 300BLK subsonic goodness. The YHM ULTimate upper receiver (“top end”) was announced in mid-October 2018, and since the government “processing” of NFA items like suppressors is painfully slow, even if you bought one right away it would still be sitting in your dealer’s safe. However, thanks to Yankee Hill and Silencer Shop, we are lucky enough to be able to give you a preview of sorts into this suppressed upper receiver for your AR15.


    YHM ULTimate Review – Table Of Contents:

    1. Overview

    2. Specifications (ULTimate And Phantom)

    3. Decibel Metering

    4. Observations

    5. Conclusions

    6. Silencer Shop Purchasing Process

    Previous TFB Coverage of the YHM ULTimate:

    YHM ULTimate

    YHM ULTimate

    YHM ULTimate Review – Subsonic 300BLK Metering


    1. Overview

    At first glance, you might be tempted to call the YHM ULTimate an integrally suppressed upper receiver. Technically, anything that is “integrally suppressed” needs to have the silencer integrated into the barrel with porting or venting to bleed off excess gas, dropping supersonic cartridges to subsonic velocities. Instead, the YHM ULTimate is a barreled upper receiver with a YHM Phantom titanium silencer permanently pinned and welded to the muzzle. The barrel/suppressor combo leaves you with a legal barrel length of just over 16 inches, acting a short barreled rifle situation. Overtop is Yankee Hill’s black Diamond MLOK equipped handguard.

    Why pinned and welded and not left in a standard thread-on configuration? My thoughts are that some shooters are not exactly excited about using pistol stabilizing braces to avoid NFA restrictions. In addition, running a suppressor under a handguard can be tricky – a standard direct thread setup has the potential to loosen with each shot. My last theory is that if YHM sold the ULTimate without the Phantom pinned and welded to a 16”+ length, less “fastidious” shooters may end up with an unregistered SBR in short order. Either way, the YHM ULTimate is set up to be a solid, no-nonsense setup.

    2. YHM ULTimate – Specifications



    Let’s take a look at the numbers.

    • .30 cal. Phantom® ULT Titanium Suppressor (YHM-4300-Ti-24) – See Below For Details
    • 9.1″ Threaded Melonite QPQ .300 BLK 1:7″ Barrel (YHM-71-T)
    • Rifle-length (12.6″) Black Diamond® M-LOK® Handguard (YHM-5343-DX)
    • Flat Top A3 Upper Receiver Assembly (YHM-100)
    • Clamp Screw Low Profile Gas Block (YHM-9384)
    • Black Plated Gas Tube (YHM-BL-04)
    • MSRP: $1,275
    • As low as $999 At Silencer Shop – https://www.silencershop.com/catalog/product/view/id/4722/s/yhm-phantom-integral-upper/

    This is one not to miss! Check out the new ULTimate™ 300 Blackout Top End! The ULTimate™ comes with a .30 cal. Phantom® ULT titanium suppressor which is pinned and welded to a 9.1″ .300 BLK barrel. With the Phantom’s length of 7.625″ and the barrel length of 9.1″, this gives the ULTimate™ a legal barrel length of over 16″. Also included is our brand new, lightweight Black Diamond® M-LOK® rifle-length handguard for a bold, sleek look. Built with the flat top A3 upper receiver assembly, it already includes the forward assist and dust cover assembly for your convenience.

    The 9.1” barrel length is about the perfect sweet spot for 300BLK performance. Short enough to be light, compact and maneuverable, but long enough for more complete powder burn, the end result is a quiet setup in the smallest unregulated package possible.

    YHM Phantom- Specifications


    Underneath The ULTimate’s rail is a titanium Phantom – historically one of Yankee Hill’s Best performing (and lightest) rifle suppressors. While it appears the Phantom may be out of production as a standalone option, it has found renewed life inside the ULTimate AR15 upper receiver

    • Sound reduction: 32 dB
    • Weight: 15 ounces
    • Length: 8.5”
    • Build materials: titanium; Inconel
    • Finish: matte black

    Published on Sep 28, 2015 – Silencer Shop

    00:44 Meter Numbers

    The YHM Phantom TI is the titanium version of the Phantom M2. It is a quick attach silencer and rated for 300 RUM down.

    3. YHM ULTimate – Decibel Metering


    I don’t live life by the numbers, especially when it comes to evaluating silencers. There are so many factors that go into suppressor buying that leaning on a machine to push out data seems shortsighted. However, as flawed as it is, decibel metering is one of the only tangible ways we have of testing silencer performance. I am lucky enough to have the opportunity to borrow a sound meter from Allen Engineering. Let’s see how the ULTimate performs with subsonic 300 Blackout.

    Environmental Variables

    My personal disclaimer: I am not a scientist, but I do play one on the internet. Decibel meter data alone, even if done correctly, is a poor way to evaluate silencers. Your personal use case, requirements and applications are more important than any list of numbers. Decide how you are going to use your suppressor and what is important to you, then use all the factors combined to make a purchase decision. When in doubt, ask. My email can be found below.

    MILSTD Muzzle (dB) – One (1) meter right; 1.6 meters off the ground.

    • 120+
    • 129
    • 130+
    • 130+
    • 133.5
    • 128.4
    • 128
    • 132.1
    • 130
    • 133.6
    • bolt drop 116.4

    At The Ear (dB) Six inches from right ear; 1.6 meters off the ground.

    • 127.1
    • 130+
    • 129.2
    • 130.6
    • 130.7
    • 130
    • 129.1
    • 128.3
    • 128.1
    • 129
    • bolt drop 118.1

    4. YHM ULTimate – Observations

    For a short barrel, the YHM ULTimate produces some decent numbers, averaging right around 130dB at both the muzzle and the ear. Honestly, to my ear, I expected the numbers to be lower; each shot was soft enough to be considered quiet, even without the use of hearing protection. As a reminder, the ground was snow covered, meaning that the meter numbers could be reading higher as opposed to shooting over standard ground cover.

    The balance between muzzle decibel numbers and ear decibel numbers could be a good sign that the YHM engineers are doing their homework. The Phantom is doing a great job of suppressing the 300BLK rounds without creating excessive back pressure that would push additional gas back down the barrel and gas tube. In addition, I didn’t notice any first round pop (FRP)* issues, even when pausing between strings of fire.

    * As a quick refresher, FRP is a phenomenon where unburned powder and oxygen are compressed under high heat within some suppressors on the first shot.

    One side effect of burying a metal tube under a handguard is heat transfer to the support hand. Luckily, the Black Diamond handguard is well vented and gives adequate space around the Phantom. However, thermodynamics being thermodynamics, if you plan on multiple mag dumps with your ULTimate, you are going to want to wear gloves and/or add a vertical foregrip of your choice.

    5. YHM ULTimate – Conclusions

    Yankee Hill Machine has always been a manufacturer that focuses on building quality products at affordable prices, and the YHM ULTimate is no different. For around $1K (depending on your dealer’s prices) you get a high-quality titanium suppressor along with a barreled upper receiver. Part of me wishes that YHM would include a bolt carrier group and charging handle as part of the package. But Silencer Shop gives you the choice to add an adjustable bolt carrier and charging handle at the same time you buy the upper.

    If you consider the fact that the Phantom usually costs $700-$750 by itself, the YHM ULTimate is a good deal without the need for an SBR lower receiver.

    Check the pricing and purchase the YHM ULTimate at Silencer Shop here.

    6. Silencer Shop Purchasing Process:

    Silencer Shop makes buying NFA items like suppressors very easy. It’s a step by step process that requires only a few clicks.

    Special Thanks: MAC Tactical (A Silencer Shop Powered-By Dealer)


    Editor In Chief- TFB
    LE – Silencers – Science
    [email protected]