The Griffin Armament 762MMG suppressor was designed to offer an M240B optimized medium machine gun suppressor to the military market.  A special Dual-Lok mount was made for it, and it was a ground up design for this purpose.  

The Link below is a link to AHAAH / HBK Pulse sound testing information, and the video is the 600rd cyclic rate test the unit was designed to be compatible with.  The cyclic rate of fire for the test was 625RPM which is inside the FN specification ROF for the 240B, which is 550-650RPM.   The suppressor was not damaged in the test.  The AHAAH suggests the suppressor is hearing safe for about 7 rounds per day, and I fired about that without hearing protection without discomfort on two occasions using a select fire trigger group.  I actually like the tone of the can, and I think it is pretty quiet, but 10 rounds a second isn't a good way to "hear" that as well as semi-automatic is.

We lock cease 20/20'd just the taper on the mount, and the suppressor screwed right off after cooling from the test without resistance or issues.  

This is the most durable suppressor I have ever designed and manufactured.  


For AHAAH / Pulse sound testing data click HERE

Product web-page

It was the most abusive thing I've done, or been present to see done to a 240B.

I don't think the gun was damaged, but I'm sure we tempered the barrel back a little and lowered its threshold for future failure at least a little.  I think the barrels can take ~1100 rounds fired one time, without a suppressor without failure, but the doctrine recommends barrel changes every 2 minutes at 200 rounds a minute, or every 400rds at "RAPID".  

100rds per minute is a sustained ROF, so if we had fired the 600 rounds in 6 minutes without a suppressor, that would be the max threshold of specification rate of fire for 600 rounds.  The 100RPM requires a barrel change at 10 minutes of sustained- or 1000rds fired at the sustained rate of fire.

There is a competitive market here for 240 machine gun suppressors, I believe the Army told me 11 brands are pursuing these, and we've already published way more information than the other companies.

The better question is whether the Army will actually be buying 240 suppressors at all IMO.    I think we didn't do what everyone else is doing and I like the can, so maybe someone else will also like the can if we're lucky.

Recoil was pretty light, but I forgot to bring gloves and had to drop my firing grip to protect my hand from burns.  Freshly ejected 240 brass will cause blistering and the skin will fall off, so it a pretty serious hazard.  I have an m192 tripod and it has a brass deflector on it that kicks cases to the right making it possible to have more sustained fire without the gun creating a pile that forces it up in back.  I should’ve probably run that for this test.

With my only control being the stock and trigger, and just a general aiming point of “low in the berm”, the gun moves around more than it otherwise would with a better grip and a more defined aiming point.

We fired a couple cases of ammo though the 762MMG last week, and for a lot of the time I was standing within 6 feet of the gun without ear protection talking to people, and it was really interesting in that it has very low ear pressure even for the 136DB shooter ear SPL it is creating.  The can had a pretty much conversational level of sound. We shot it at night and it had nearly no light signature.  In desert sand the gun had no visible ground disturbance.  

It was our first foray into something for which there is little to no consumer market overlap.  The can would be impossible to damage with any shoulder fired magazine fed full auto platform.

The suppressor is capable of all the things the FN 240B is rated for by the military.

It can do the 600rds cyclic (which is not a specified rate in the manual), as well as the two minutes at rapid 200rds/minute, and the ten minutes at 100rds/minute sustained prior to barrel change (in the unlikely event a barrel change is necessary).

It would be very unusual for the gun to be pushed beyond the published fire schedules, and detrimental to the continued safety and service life of the barrel.

Typically there is a spare barrel or two for three total barrels per gun.  You will probably only see three barrels in a static position or vehicle.  Carried barrels would probably be a single spare.  Depending on the severity of the conflict, they may not be required at all.  It would probably make sense to have one can per barrel, but it is still nice for the gunner to be able to break the gun down for different purposes (mett-tc) without going into every contingency in detail.

In nine years in the Infantry, I never saw a 240 go through more than 400rds in an engagement and never saw a barrel changed outside of training.  Most of the time a large part of 400 rds was simply unnecessary fire by guys who wanted to throw more rounds downrange (like a show of force).  I believe a ukd pop up qual involves at least 12 exposures out to 800meters, and gets fired with ~182rounds of ammunition.  In other words the std is engagement of 12 target exposures with 182 rounds.  So theoretically it should require 26 targets to require ~400rds of ammunition in an engagement with 15.16 rounds allotted per textbook engaged target.

On the variable rof, I think some of the suppressors with coaxial chambers get overwhelmed with dwell pressure and start to increase backpressure and rof during an extended burst.