When I first saw the new crop of Sig Sauer rifle suppressors with 
their iconic shape, I knew that look was familiar. Then it hit me. It’s 
almost a dead ringer for the US Navy’s Mk-54 Antisubmarine Torpedo. 
Coincidence? I think not…

Coincidence? Hmmmm…….
 
There
 are a couple of differences. Don’t run this suppressor “wet” like the 
Mk-54. Rifle-sized pressures and operating “wet” don’t usually go 
together, at least not safely. Another difference is that the 
Sig Sauer SRD762Ti-QD
 is noticeably lighter than the Mk-54, probably because of the use of 
Titanium. That and the much smaller size. Last, but not least, the Sig 
SRD762 is way quieter when it goes off. Oh, and as far as I know, the 
Sig SRD762Ti-QD doesn’t have a magnetic detonator either.
Thanks 
to some help from our friends at Silencer Shop, I got my hands on a 
brand-spankin’ new SIG Sauer SRD762Ti-QD suppressor for some serious fun
 (work and highly scientific testing.) As the name implies, this is a 
.308 / 7.62mm suppressor, but it’s rated for up to 300 Win Mag and any 
other cartridge that has same or smaller diameter and pressure.
Sig
 offers two different designs of the SRD762 suppressor and two different
 mounting systems, so in total there are four different models in the 
SRD762 family.
There is a standard SRD762 and an SRD762Ti. The 
standard model is made from Inconel 718, a Nickel Alloy Stainless Steel.
 The “Ti” model uses Titanium as the name implies. Basically, you’ll 
want to choose the Iconel version for heavy and abusive use. The 
Titanium model uses lighter material so it can be a bit bigger without 
making the suppressor heavier. Bigger means more air inside, which means
 less pressure and less noise. Make no mistake, the Titanium version is 
plenty durable, but if you’re going to use it in a sandbox, maybe choose
 the Iconel model.
Both models are available in fixed thread mount
 or QD (quick detach) mount configurations. The new QD system is pretty 
darn clever, and we’ll get into that more in a minute. The fixed thread 
models of the SRD762 models use ⅝-inch x 24tpi threading.
Due to 
the different combinations of materials and mounting systems, the four 
models have different dimensions and sound suppression performance. 
Here’s a quick summary.
 
Tubeless
Most
 suppressors have a series of baffles that are assembled and then placed
 inside of an exterior sleeve or tube that contains everything and holds
 the system together. Many rifle suppressors are permanently constructed
 this way to handle the crazy high pressures of rifle cartridges. The 
result is that part of the assembly, and associated weight, serves no 
real purpose other than structural support. Additionally, the space used
 by the support tube means less sound-suppressing interior volume inside
 for any given exterior size. From a pure noise-reduction perspective, 
the bigger you can make the interior volume, the better.

The QD package mount system is actually two pieces – the suppressor mount itself and a muzzle brake insert.
 
The
 idea is that by constructing the entire silencer completely from the 
baffles, there is more space for air inside and less weight allocated to
 structural support only. This is why you’ll see a series of ridges all 
along the suppressor exterior. Those are the weld joints where the 
baffle rings are attached to each other. It’s a clever idea. Plus, it 
looks kind of cool. The weld joints are perfectly uniform, so they don’t
 look like weld joints. They look more like some form of decorative 
texturing pattern.

The suppressor body is made of a stack of baffle rings welded together.
 
The blast chamber at the base is made from one solid hunk of metal and the baffle rings extend from there forward.
Mounting System
The mounting system on this suppressor is, well, brilliant. Here’s why.
Direct-thread
 mount systems are easy and stable. You just screw it onto a threaded 
barrel and start shooting. The downsides are that it doesn’t come on and
 off easily and your point of impact may vary between on and off 
episodes as the silencer mounts a little differently each time. Of 
course, if you leave a suppressor on one rifle forever, this is a moot 
point, assuming you don’t remove it for cleaning or maintenance.
Direct-thread
 mounts also do a good job of keeping the suppressor perfectly aligned 
with the bore, so you don’t run the risk of a baffle strike. That’s when
 a very, very slight misalignment of suppressor and bore cause your 
bullet to whack the inside of the silencer on the way out. That’s bad, 
especially since you forked over a hefty price to the company, paid $200
 in tax, and waited months to get it. Trust me, it a baffle strike 
totally ruins your day. Don’t ask me how I know.
When using a 
direct-thread mount, make sure that your don’t use the crush washer 
that’s already likely between your barrel and existing muzzle device. 
Normally, crush washers are used to “time” muzzle devices like those A2 
flash hiders that come on most AR-type rifles. By “timing” I simply mean
 alignment. The flat part of the muzzle brake needs to be facing the 
ground while the open slots face outward and/or up. The crush washer 
does just what is says, and compresses as you tighten the muzzle brake. 
It will let you keep turning, up to an additional full turn or more, 
once it’s tight so you can get perfect alignment of the muzzle device. 
Crush washers flex and give, and, therefore, open up the possibility of a
 baffle strike as they don’t provide for an absolutely square mount to 
the bore line. Make sense?
When you use a suppressor that mounts 
on a special muzzle device like a flash hider or brake, you get a couple
 of benefits. First, it pops on and off easily so you can pack it in 
your bag or switch it between guns. You can shoot unsuppressed or 
suppressed at will. Second, When you remove the silencer, there is still
 a muzzle device there to protect the threads and do the things muzzle 
devices do like brake recoil and hide flashes. Third, a compatible mount
 and muzzle device keeps your suppressor aligned perfectly with the bore
 every time you install it, thereby preventing baffle strikes and 
keeping your point of impact consistent from session to session.
Here’s
 the trouble with most suppressor mount systems. Unless you’re using a 
muzzle flash hider mount where orientation doesn’t really matter, you 
still have to time the suppressor mount and muzzle device so it’s 
aligned correctly. You can’t use the normal system, a crush washer, for 
the reasons we just described. Instead, you use one or more flat washers
 of different thickness so that when you tighten the muzzle device down,
 it’s in the correct orientation. This is kind of kludgy.
Here’s 
what Sig did to make a better mousetrap. The suppressor mount and muzzle
 device are separate, so there are three pieces at play: the mount, the 
muzzle device, and the suppressor itself. The mount has no specific 
orientation. Just remove all washers from your threaded barrel, degrease
 everything, add a little Rocksett, and screw it on tight. It’s 
symmetrical all around, so, however, it lands on the threads is fine. 
The muzzle device screws into the interior of the suppressor mount. You 
can change muzzle devices without moving the suppressor mount at all. 
Sig offers a variety of muzzle devices that fit into the suppressor 
mount so you can decide if you want a muzzle brake or flash hider. Since
 some of those devices need to be timed (oriented properly), you insert a
 large crush washer between the suppressor mount and muzzle device. That
 works because when you mount the suppressor, it only contacts the 
suppressor mount and not the muzzle device. The muzzle device just slips
 inside of the suppressor body. There is no risk of the crush washer 
causing misalignment baffle strikes because it plays no direct role with
 how the suppressor is mounted.

The mount itself is already installed on the rifle barrel. Muzzle devices are just inserts that fit into the mount.
 
The
 bottom line is that you get a quick attach and detach mount. The 
suppressor goes on the same way every time and in perfect alignment. You
 can do whatever you want with Sig Sauer compatible muzzle devices 
without worry of impacting suppressor alignment. It’s simple but 
brilliant.
Large threads allow the suppressor to screw on to the 
QD mount with two turns. A locking tab makes sure it won’t come off 
during use. Just press the locking tab before removing the suppressor 
from the mount.

The Micro-Brake installed into the suppressor mount.
 
While
 we’re on a suppressor mount epistle, I should mention one more thing 
about the suppressor mount system. It uses the new Taper-Lok system. The
 complete system includes a threaded barrel with a tapered section 
behind the threads. The mount has a mirror image taper and thread 
pattern. The barrel and mount pressure fit together via the tapered 
sections and lock with the threading. If your barrel has no tapered 
section, that’s fine too, the tapered section within the mount just 
presses over the ridge at the base of the threaded section. The idea is a
 more solid and perfectly straight mount that won’t easily loosen. Sig 
says that it takes 20% more force to remove the mount than to apply it 
due to the effect of the taper, so the devices are more likely to stay 
in place through heavy shooting.
OK, so that was a lot of 
explanation, but the whole approach to the mount system is one of the 
biggest areas of different with the Sig suppressor line.
Testing
I
 tested this model on a Daniel Defense DDM4V5 300 Blackout rifle, mainly
 because I wanted to hear the sound of the bolt operating. Just kidding,
 but when I did start shooting Sig Sauer 220 grain subsonic 300 Blackout
 ammo, that was the loudest noise – the bolt moving back and forth. 
Whoa! That was cool and got major attention at my outdoor range. The 
even better part was the relative instability of those big, lumbering 
220 grain subsonic bullets. As soon as they struck a target, they would 
tumble and go whizzing off into the backstop making all sorts of awesome
 sound effects.
I also shot a variety of 300 Blackout supersonic 
ammo. Of course, the sonic crack is still there, but that’s moving away 
from you. The suppressor did a fine job of negating the muzzle blast, so
 the shots sounded more like compressed air being released from a tank 
from the shooters position.

The suppressor body locks onto the mount with a locking tab. Just press and you can then unscrew the silencer from the mount.
 
One
 thing I did notice was a significant tightening of groups when I 
mounted the suppressor. I set up a target 100 yards down range and fired
 groups with both supersonic and subsonic ammunition with only the 
Micro-Brake muzzle device in place. I then screwed on the suppressor and
 reshot groups. Both super and subsonic groups were noticeably tighter 
when shooting suppressed.
I also took this opportunity to check 
for point of impact shift between suppressed and unsuppressed shooting. 
For the supersonic ammo I was using, there was about a one-inch vertical
 shift in point of impact downward when I added the suppressor. For the 
subsonic ammo Sig Sauer ammo, there was about a ½-inch shift to the 
right at 100 yards when I added the silencer.
Price
I like
 this silencer, especially the mounting system. The QD mount is 
forgiving when crud starts to accumulate, so you’ll still be about to 
mount and un-mount it without undue effort. The separate muzzle device 
and suppressor mount design is a great idea and works really well.
The manufacturer suggested retail prices of the four different models are:
SRD762 Direct Mount: $595 
SRD762Ti Direct Mount: $795 
SRD762-QD: $695 
SRD762Ti-QD: $895
Check Silencer Shop for street prices and availability.