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Old December 16, 2007, 10:47 AM   #1
Bartholomew Roberts
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Join Date: June 12, 2000
Location: Texas and Oklahoma area
Posts: 6,784
Range Report: Ops Inc. 16th Model 5.56mm Suppressor

Last Spring I acquired an Ops 16th Model 5.56mm suppressor. I thought I would give an updated range report on its use the past couple of months. I’d also like to thank Snarlingiron, who was kind enough to be the photographer and make this a multimedia range report.

Ops Inc. is a company that has been making suppressors for the military for almost twenty years now. Previously, the company has served only the military market and not been interested in the civilian market. The company is known for its “back over the barrel” suppressors that use a two point mount. This design allows the suppressor to be more compact by placing the expansion chamber behind the muzzle. The two point mount also makes for a more consistent shift in point of impact.

Here is a picture of the Ops Inc. two-point mount consisting of a two-port muzzle brake and a barrel collar. I have removed the protective collar around the two-port brake so you can see the external threads that the suppressor mounts on.

Ops Inc. makes two types of muzzle devices, the two-port brake and a version with either an A1 or A2 flashhider. The two-port brake is a decent muzzle brake; and offers some recoil-reducing benefits (as well as the normal blast and noise associated with a muzzle brake). It extends past the bare muzzle about one inch. Flash is also quite noticeable as two balls of flame shoot out either port. The main advantage the two-port brake offers is that it also acts as the primary blast baffle and extends the life of the suppressor. The logic is that it is easier to replace the $80 muzzle brake instead of the baffle stack of a much more expensive suppressor.

The flash hider mount doesn’t offer the same advantage of taking the brunt of the blast; but it does help make the rifle blend in with other military equipment and give the same type of flash suppression as the A1 or A2 models. If you are concerned about this, ADCO offers a 3oz flash hider cover that mounts over the two-port brake using the same external threads as the suppressor. It adds two inches past the bare muzzle and is an open, prong-type flash hider. It is about as effective as the A2 flashhider; but changes the flash to a tiny pencil of flame instead of a starburst. The two advantages of the cover are that it keeps the blast from annoying your neighbors on the firing line and you still seem to get some advantages from the brake, overall though I probably wouldn’t purchase it unless I really needed to do one of those two things and was shooting a course of fire that generated enough heat that the suppressor was impractical. There was no shift in zero using the flash hider cover. Here is a picture of the two-port brake with the flash hider cover installed:

I recently took a class where we had an aggressive round count (about 720 rounds in one day) and the ADCO Flash Hider cover got stuck on the barrel. Apparently, just a few external threads were exposed enough that carbon build up locked the flash hider cover on. We ran a knife through the flash hider slots and levered the cover off. This does not happen using the Ops thread protector or the Ops Inc. 16th though. Oddly enough carbon build up doesn't happen when you use no thread protector at all either - the muzzle blast blows the carbon off the threads.

Currently, Ops Inc makes the 12th Model suppressor that is used on the military Mk12 mod 0 and mod 1 Special Purpose Rifles (SPR). These are basically AR15s set up for mid-range precision shooting. They also sell the 12th model now to civilians. One problem with the 12th model though is it requires specific machining of the barrel in order to mount the collar. Ops Inc. makes a smaller 14th and 15th model suppressor that mounts the collar on the standard military barrel step; but these suppressors are designed to be more compact and are not as quiet. The 16th model combines the mounting system of the 14th and 15th models with the baffle stack of the 12th model. The result is a can that is 0.5” shorter than the 12th model and 1oz lighter; but comparable in sound reduction.

Sound reduction is a major factor for many civilian shooters; but there are other factors to consider as well. These include shift in point of impact from the unsuppressed point of impact and durability. So far, I’ve shot 7 sets of groups (five rounds unsuppressed, five rounds suppressed) at 100yds using the rifle shown. The shift in zero appears to be a fairly consistent 1.5” low with the suppressor attached. There have been a two sets that didn’t show this; but one thing all of those sets had in common was poor shooting by the shooter (2” group sizes). Here is an example of a typical set of groups. The one stray round is where I mistakenly started a new group on the wrong diamond:

As to durability, the Ops Inc. 16th model is warrantied for 30,000 rounds provided you do not use military surplus or Wolf ammo through the suppressor. This means that the suppressor will probably outlast the barrel in most cases. No cleaning or maintenance is necessary either.

However, let’s get to sound reduction because I am sure that is what most people are interested in. Since I don’t have extensive sound testing gear, I am just going to give my subjective impressions. First, there are two elements in determining how quiet a shot is – one is the sound at the muzzle and the second is bullet flight noise. Because the .223 is supersonic, the bullet has its own accompanying sonic boom. This is more noticeable when shooting in an enclosed area than in the open.

Shooting on an open firing line with a single berm downrange, the 16th Model sounded much like an unsuppressed .22LR rifle. It was quiet enough that you could hear the bullet impact the berm (this may have also been bullet flight noise reflecting off the berm) from the 100yd targets. Shooting on an enclosed tactical range with a U-shaped berm, the experience was a little different. You could hear the bullet flight noise reflected off the berms as the round traveled downrange giving it a kind of zip/whoosh sound that reminded me of air tools in a garage. The sound there was noticeably louder; but sounded less like a gunshot. We were sharing the range with a great group of people with an Anschutz .22LR target rifle. Here the unsuppressed .22LR was definitely quieter.

The final issue I’ll discuss is gas blowback and heat. For those who haven’t shot suppressed weapons before, the way they work is by delaying the escape of hot, supersonic gases until they can cool. The cooler gases do not create the supersonic crack at the muzzle. One side effect of this is increased backpressure in the system that causes gas to escape from the ejection port, charging handle and almost any other place it can get out. Another side effect on direct-gas impingement rifles like AR15s is that the bolt cycles much faster than it normally does due to the increased pressure and dwell times.

Here I used a Gasbuster charging handle to reduce the amount of gas in the face. For the first 10 rounds from the nice clean suppressor, I didn’t notice any gas at all. After we got it nice and carboned up though, you would occasionally get the shot of gas in the eyes despite the Gasbuster. We were outdoors so the eyes didn’t tear up too much; but most people would probably find it unpleasant. It was kicking quite a bit of gas out of the ejection port as well, so I can’t say that the charging handle was the only source. How much gas blowback you get seems to depend on rate of fire, heat, and whether you use lubricant in the suppressor to further dampen the sound of the first 1-5 rounds. Just target shooting with it, I rarely have an issue with gas blowback. When I am dumping 10-15 rounds into a target as fast as I can pull the trigger, more noticeable. Also adding lubricant (2-3 drops) into the suppressor appears to increase blowback.

One more aspect of the backpressure, the increased backpressure also means a much dirtier weapon. The lube dries off the internal parts quicker since it is essentially getting the "blow dry" treatment from increased heat and backpressure and more carbon is blown into the chamber as well.

On bolt velocity, I will probably need to run a heavier buffer. Right now I have only a standard carbine buffer and a very heavy MGI buffer (7oz). The rifle will not run reliably unsuppressed with .223 loads with the MGI Buffer due to the midlength gas system that reduces gas pressure. Suppressed it runs reliably with both the standard carbine buffer and the MGI buffer; but it is really slamming that bolt carrier group with the standard carbine buffer. Normal ejection for this rifle is about 3:30-4 o’clock. With the suppressor installed, it is ejecting at 12:30-1 o’clock and some of my older mags no longer work because they can’t push rounds into place fast enough.

Picture of 16” midlength with suppressor to give an idea of size:

All in all, I really enjoyed the experience and hope this post helps anyone in the market for the world’s most effective muzzle brake/flash hider/OSHA approved hearing protection.
Bartholomew Roberts is offline  
Old December 16, 2007, 12:22 PM   #2
Senior Member
Join Date: June 17, 2006
Location: Seattle, WA
Posts: 179
well written range report, sir. good photos.
47.5N 122.2W
raymond- is offline  

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