Yankee Hill Machine's Phantom Suppressor
By Todd Burgreen

Everyone is dubious of something that promises to do several tasks well versus a specifically designed product. The underlying concern is that compromises involved with making something adaptable invariably leads to compromises in performance. The Yankee Hill Machine (YHM) Phantom 7.62 Sound Suppressor refutes this assumption. Many civilians agonize over what suppressor to buy due to the cost and time invested in pursuing a BATF tax stamp. At a minimum, upwards of $750 is spent on a quality suppressor along with the $200 for the tax stamp not to mention the bureaucratic paperwork and waiting involved. Yankee Hill’s Phantom 7.62 Sound Suppressor offers the ability to easily function on several different weapons and calibers, thus a flexible alternative to purchasing a suppressor that is relegated to one rifle or caliber.

YHM’s Phantom 7.62 Sound Suppressor is a .30caliber suppressor utilizing Mark White’s Sound Technology, Inc.’s patented (US Patent #7,073,426) baffle design. In fact, the YHM website calls the Phantom 7.62 suppressor a collaborative effort between the two companies. Make no mistake; YHM is the manufacturer, quality control agent, and distributor of the Phantom suppressor. The Phantom 7.62 Sound Suppressor is manufactured from Chrome-Moly steel and features a matte black Parkerized finish. Its overall length is 8.5 inches with a diameter of 1.6 inches and weighs 25ounces.

Besides manufacturing and proofing the Phantom suppressor with Sound Technology’s patented baffle design, YHM created the Phantom Flash Hider (patent pending) muzzle device that enables the quick mounting/dismounting (QD) of the suppressor. Hand tightening is all that is needed with the Phantom Flash Hider to hold the suppressor firmly in place. Conversely the suppressor can easily be removed via hand pressure when no longer needed. The Phantom Flash Hider supports the suppressor in two places helping to ensure bore alignment. A patented gas seal keeps the Phantom Flash Hider threads clean so the suppressor will not bind when removed from a weapon no matter how many rounds are fired. The QD Phantom Flash Hider contributes to the adaptability of the Phantom suppressor. The Phantom Flash Hider is available in 5/8”-24RH, 9/16”-24LH, 9/16”-24RH, and M14mm-1LH thread patterns. By installing multiple Phantom Flash Hiders on different weapons one Phantom suppressor can be utilized on multiple weapons of different calibers. This is what makes the YHM Phantom Sound Suppressor so utilitarian by enabling the 7.62 Phantom Sound Suppressor to work with not only with 7.62x51 (.308 Win) but also .300WinMag (yes, the Phantom is guaranteed for use on the 300 WinMag), 7.62x39, and 5.56/.223 to name a few calibers. Basically, if the bullet diameter is .30caliber or less the 7.62 Phantom can be used. Of course verify with YHM if any “exotic” calibers or applications are being contemplated. The limiting factor is getting the Phantom Flash Hider adapted to your barrel. The Phantom suppressor is even usable on AK Krinkov style weapons, chambered in 7.62x39 or 5.45x39, once a custom machined adaptor fitting the Krink’s 24mm threads is fashioned. The 7.62 Phantom is designed to reduce muzzle noise up to -32db. The Phantom 7.62 does sacrifice -3db rating compared to YHM own suppressor specifically designed for .22 calibers. This is a result of the increased diameter of the .30 caliber hole versus a .22 caliber hole losing some sound suppression efficiency.

The Phantom 7.62 suppressor was mounted and tested on a variety of weapon platforms consisting of a Rock River AR-15 chambered in 5.56, Century Arms M72 AK chambered in 7.62x39, Armalite AR-10A4 chambered in 7.62x51(.308 Win), and finally a Weatherby Custom TRR rifle chambered in .300 WinMag. It was as simple as installing a Phantom flash hider on each weapon. Conveniently, each rifle had a barrel with a pre-existing thread pitch that accommodated the Phantom flash hider. The ARs and AK have the Phantom flash hider left on permanently. The Phantom flash hider is not only an ingenious mounting system for the suppressor body, but also an effective flash hider in it own right. The Phantom flash hider is added to the .300 WinMag rifle in lieu of the attached muzzle brake when the suppressor is to be used. The brake is missed too much in terms of recoil management to leave the Phantom flash hider on full time.

Conversations with YHM’s Steve Dwight indicated that most users of their sound suppressors do not use subsonic ammunition in conjunction with the Phantom Sound Suppressor. The loss in terms of ballistic capability combined with the cost of specialized sub-sonic rifle ammunition and difficulty of finding quality subsonic ammunition being the root reasons. Many users feel the Phantom’s ability to minimize muzzle blast is well worth using it even though the prominent sonic crack is still present when using standard supersonic ammunition.

The Yankee Hill Phantom 7.62 suppressor was tested over an extended period of time consisting of numerous range visits. The advantage of the YHM QD method became quickly apparent and appreciated as the Phantom suppressor was shifted between the different rifles. Individual weapon’s point of impact (POI) did shift when the suppressor was installed. This is to be expected whenever hanging something off the end of a rifle barrel. It changes the barrels harmonics. What was closely monitored was if the point of impact stayed consistent once logged in for when the suppressor was installed on a specific rifle. Another important consideration for a suppressor is if the accuracy of a rifle is impacted negatively. This is important if long range work is considered with standard supersonic ammunition. Standard loads used were Federal Match 168gr for the AR-10A4 7.62x51/.308 Win, Black Hills Ammunition 55gr FMJ and 69gr Match for the 5.56 Rock River AR-15, 190gr Match for the Weatherby .300 WinMag, and Wolf Military Classic 124gr FMJ for the Century Arms M72 AK. Every rifle’s point of impact behaved directionally different when the Phantom suppressor was installed, but stayed consistent between the removing and re-installing the Phantom suppressor. POI shifted no more than a couple of inches left/right and up/down. Group sizes generally stayed equal or increased only slightly when compared to groups fired without the suppressor installed.

Engel Ballistic Research (EBR) is a primary source of quality subsonic ammunition due to the variety of calibers and loadings offered. Another reliable source for .308 Win subsonic loads is Corbon. Engel Ballistic Research’s (EBR) 5.56 NATO/.223 Ultra Stealth Match Subsonic (63gr Sierra Match bullet), 7.62NATO/.308 Thumper Subsonic (180gr bullet), .300 WinMag Subsonic (220gr bullet), and 7.62x39 Jackhammer Subsonic (220gr bullet) loads were tested. None of the EBR loads use fillers and all are loaded with accuracy in mind. The 5.56/.223 Ultra Stealth is designed intentionally not to cycle the rifle’s action for the maximum efficiency in terms of sound reduction and performs well in ballistic gelatin tests tumbling within 2-3 inches of penetration. Readers will find that subsonic loads do not typically cycle in an automatic rifle. This is not a great hindrance as an AR rifle with a tactical latch is almost as quick to cycle manually as a bolt action. The 7.62NATO/.308 and .300 WinMag loads are created from match grade components for ultimate accuracy. The 7.62x39 Jackhammer load is unique in the industry in that it is designed to cycle in M16 platforms with or without a suppressor mounted in both semi-and full automatic modes. EBR reports AK weapon platforms can be made to work with the Jackhammer after slight re-working of the feed ramp. The light recoil of the subsonic Jackhammer load makes it extremely controllable in full automatic mode.

Subsonic rifle ammunition is a different creature ballistically compared to standard loads confined to not much more than 150 yards distance for accurate shooting due to external and terminal ballistic reasons. It was determined that either a detailed log had to be kept for scope adjustment or scope reticle hold-over point written down when going from supersonic ammunition to the more specialized subsonic rounds. The subsonic loads dropped approximately 16-20 inches when fired at 100 yard targets compared to 100 yard zeros with the standard velocity loads. Windage adjustments were also necessary measuring anywhere from 4 to 8 inches left or right depending on the rifle. A user will definitely have to familiarize oneself with these range behaviors with different weapons and keep detailed records if contemplating switching back and forth between standard loads and subsonic loads. Several range visits would be prudent in confirming these findings.

The range experience was rather subjective in evaluating the YHM Phantom suppressor’s raison d’être - ability to lessen or dampen noise. No high tech auditory monitoring gear was used testing the Yankee Hill Machine Phantom 7.62 suppressor; just expectations based on previous experiences along with suppressors from other manufacturers on hand for direct comparison with ammunition from the same lot umber being fired out of multiple suppressors. The more one studies suppressors as a subject matter the more one realizes even with the audio equipment there are many variables in getting an accurate db reduction reading: i.e. atmospheric conditions, installation method of the suppressor, type of weapon used, first round pop phenomenon (FRP), etc. EBR’s website is an informative place to start searching into the facts of sound suppressors’ capabilities in combination with subsonic ammunition.

It is quite interesting to be sitting or lying behind a berm as rounds pass overhead. This was done to both get an idea of how effective the YHM Phantom was in reducing the sound of a round fired and masking the location of the shot. While this may strike many as unsafe or irresponsible, it was managed as closely as possible to ensure safety. It was no different than working the target pits at a rifle competition. The supersonic rounds were clearly audible, but the Phantom’s ability to mask the normal muzzle blast signature made identifying where the shot came from more problematic. This is further enhanced the farther away the shooter is from the target. The EBR subsonic rounds were very impressive in this range test format. The sound of a round striking a steel target near your position with no prior warning is eerily impressive. This was the case when the shooter is 100 yards away firing over your head at a target beyond you. This minimal firing signature resulted from combining the YHM Phantom suppressor and EBR ammunition. The Phantom suppressor was also analyzed when standing next to a weapon firing. The use of hearing protection was not needed, especially with subsonic ammunition. The Yankee Hill 7.62 Phantom held its own in direct comparison with other sound suppressors during the entire evaluation; many of which cost significantly more than the Phantom. The YHM Phantom 7.62 Sound Suppressor succeeds in achieving adaptability while remaining effective as a suppressor.

Yankee Hill Machine Company, Inc
20 Ladd Ave, Suite 1
Florence, MA 01062
(413) 586-1326

Engel Ballistic Research, Inc
(512) 360-5327

Sound Technology
PO Box 39
Pelham, AL 35124
(205) 664-5860

This article first appeared in Small Arms Review V12N10 (July 2009)
and was posted online on June 15, 2012


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