Good afternoon everyone and thank you for joining us for another edition of TFB’s Silencer Saturday brought to you by Yankee Hill Machine, manufacturers of the YHM R9 suppressor. Last week we discussed the Silencer Central Banish 30, a modular titanium rifle suppressor. This week I’d like to take a closer look at those all important three lugs that attach some suppressors to submachine guns and pistol caliber carbines. Probably the most well known of the quick detach mounting solutions in the silencer world, the three lug system has been incorporated into pistol caliber cans by almost every manufacturer. We’ll take a look at the new YHM 3-lug mount for the R9 as well as the options available from Dead Air and SilencerCo.
In today’s article:
- I just joined to PEW Science. Jay is certainly an expert in his field and I look forward to digging through the data and sharing a bit of his observations. If you aren’t familiar with PEW Science, they offer various levels of memberships to access silencer test data and analysis – including reports that are free for anyone. Check them out for yourself.
- The ASA is holding a Thanksgiving membership drive and giveaway contest. See all the details here.
SILENCER SATURDAY: One Host, Three Lugs, Three Cans
The history of the three lug mount is fairly vague, with the original patents/designs likely buried deep in a well organized filling cabinet in Germany. Rumor has it that the original purpose of the three lug mount was for using blank firing adapters. Barrels with three lugs made their first appearance in 1966. References to the initial 3-Lug use can be found in the out of print book called Project 64: The MP5 Submachine Gun Story.
In 1988, Tim Bixler was the inventor of a U.S. patent for a “Lugged Coupling Apparatus”. The summary mentions that the design can be used to mount suppressors:
Coupling apparatus for securing a shaft to an externally threaded member comprising:
- a cylindrical collar member having internal threads at one end to be threadedly received on the threaded member and at its other end a series of circumferentially spaced internal lugs extending radially inward to define a central opening and a series of circumferential apertures between the internal lugs,
- each said collar internal lug having a long longitudinal raised side and a short longitudinal raised side which define inwardly facing recesses there between, and
- a cylindrical shaft member having a plurality of circumferentially spaced external lugs at one end extending radially outward from the shaft,
- said shaft member having a diameter sufficient to be slidably received through the central opening of said collar member and said external lugs configured to be slidably received through the apertures of said collar member and pass over the short side and engage the long side of said collar internal lugs upon relative rotation between said collar and said shaft members, whereby
- when said collar member is threaded onto said threaded member in one direction said shaft external lugs will become seated in the recesses of said collar internal lugs and said shaft will be drawn into firm engagement on the threaded member to securely connect said shaft member to the threaded member, and
- when said collar member is rotated in the opposite direction relative to the threaded member said shaft external lugs will become unseated from said recesses and pass over the short sides of said collar internal lugs allowing said shaft to be removed from said threaded member and said collar.
2. Summary of the Invention
It is therefore an object of the present invention to provide a coupling apparatus which is particularly suited for use on firearm barrels to quickly and easily attach flash hiders, silencers, grenade launchers, blank adapters and the like.
While the majority of today’s 3-lug mounts use a spring-loaded mechanism for a push-on, twist-lock attachment, some versions like the B&T TP9 3-Lug adapter use a slip on and tighten mechanism that is more secure, but slower to attach and detach.
Shooting three suppressors
Before you ask, after today’s range session I still believe that the YHM R9 beats out the SilencerCo Omega 9K and basically ties the Dead Air Wolfman in suppressing short barreled pistol caliber carbines. Whereas the Wolfman is a modular suppressor with wipe capability, it is also heavier and costs twice as much. It really comes down to personal requirements.
I still owe you all a direct comparison for these three models.
Unfortunately, none of these three cans share the same thread pitch for the mounting systems, so you can’t mix and match three lug devices.
I have had some issues connecting the SilencerCo old style three lug device to some three lugs barrels – the device “bottoms out” before being able to make the turn to lock the spring mechanism in place.
The quietest 9mm PCC/SMG suppressor I have tested is the GSL Phoenix: an endless amount of internal volume makes hosts like the SP5K nearly silent. One requirement for the Phoenix’s three lug mount is that it suggests using a smooth thread protector rather than the standard knurled version. I’ve used both without issue, but always follow manufacturers recommendations.
Even though the 3-Lug suppressor attachment system has its downsides, it is a near perfect match for pistol caliber carbines and submachine guns. What are your experiences?
Thanks for reading. Be safe, have fun and we’ll see you here next weekend for another Silencer Saturday.
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