Sound moderators, supressors or “silencers” as non shooters like to call them have been a controversial subject over the years. First off the bat I would like to debunk the “silencer” myth and give a brief outline of what moderators are actually for…

Many people believe they know something because they have seen it multiple times on the Television. Most people have watched a spy thriller or a war film and seen a person shooting a gun with a black cannister like device screwed on it. In the film the shot is depicted as totally silent. The unsuspecting victim turns clutching himself in horror..
Now to reality. A moderator or supressor do exactly as the names suggest – they reduce noise. They do not make it disappear completely. Standing near to a supressed rifle using standard ammunition would leave you in no doubt that the gun was firing.
Bullets from most rifles are travelling at supersonic speed. Breaking the sound barrier creates a very loud crack which the moderator cannot lessen. The moderator reduces noise at the muzzle which is caused by the rapid exansion of hot gases when a shot is fired. The gases are slowed as they travel through the moderators baffles creating a smaller noise. In essence it simply controls the expansion of gasses.

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Cutaway of the Jet-Z thanks to Hamond rifle.

You may want to take a look at this site www.hamondrifle.com which has some excellent information and CAD images showing gas flow in moderators. Hamond also provided us with the cutaway image of the Jet-Z above which we are very greatful for (I didn’t fancy cutting this one in half!).
Controlling gas expansion reduces noise by around 20-30db at the muzzle which gives significant relief to the shooter in terms of hearing damage. I still wear hearing protection when using a moderator – it is still quite loud!

The other useful things that moderators do is minimize recoil and muzzle flash. The muzzle flash reduction has little value for sporting shooters but is certainly an important factor for military and LE. The recoil reduction is a huge bonus. Not because recoil is unbearable but due to the loss of sight picture it causes. If you want to spot your own shots through the scope and make accurate follow up shots then minimal recoil is a huge advantage.

Choosing a moderator.

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Selecting a moderator can seem pretty daunting. There are many options and sizes available. Of course it depends on your requirements which options you select. You should firstly check which thread you have on the end of your barrel. If you don’t have a thread then have a gunsmith put one on there. I asked Mik at Dolphin Gun to thread the end of the Trueflite barrel on the Precision rifle build. He suggested an M18x1 thread. I would therefore require a moderator with the same thread (there are many thread options which suit different barrel types).

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Mik had cut a perfect M18x1 thread already..

I would be using the rifle with a scope mounted very low therefore a slimmer moderator would be a sensible choice. Weight is another factor you must consider. Added weight right at the end of the barrel can get tiresome if you are shooting in practical type scenarios (standing/kneeling/running). If most of the shooting is off a support/bag/bipod then weight may not be such an issue. Finally I would say you get what you pay for. Accuracy boils down to precision of engineering if the shooter does his job well. Presicion costs more. The tooling needs to be high quality and relatively new. The engineer making the item needs to know what he is doing and the QC team need to be on point. All that adds up.
Last of all make sure you are legally allowed a moderator. In the UK we must apply for a slot on our firearms licence named for the moderator before we can purchase one. All countries will be different so check the law before trying to buy anything.

I ended up getting hold of the Ase Utra Jet-Z compact with an M18x1 thread. Ase Utra have an excellent record among European shooters and their Jet-Z compact ticked all the boxes – slim, light, efficient.
I picked up the .30cal rated version as it is listed as satisfactory for the .260rem and ideal for .308. I have rifles in both calibers which require moderators so I am hoping they can happily share one.

Jet-Z Compact features.

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The box contains moderator, thread protector and instructions.

Ase Utra have been making sound moderators since 1994. They currently manufacture over 10,000 units per year for use by civillians, military and LE. They are a widely respected company due to their innovative designs and great quality/durability.
The Jet-Z series is named after the patented baffle system. Baffles are pieces of metal which create a path for gasses to expand into. Certain layouts (way beyond my knowledge) slow gasses significantly thus reducing the noise at the muzzle.
I opted for the compact model due to its slim profile. Ase have numerous other options within the Jet-Z range which all look fantastic. Something I may consider for the AR in future..

The Jet-Z is made of steel so it is incredibly durable. Ase have built it to withstand military grade abuse. The only thing you need to watch out for is rust. When you finish using the moderator, let it cool and remove it from the rifle. When you get it home give it a good spray of penetrating oil inside and out (Ase recommend WD40 in the literature).

The Jet-Z comes with a barrel thread protector which you would be wise to use as it helps protect the thread and the barrel crown (important for accuracy). Luckily Mik from Dolphin had already made me a thread protector which is indistinguishable from the barrel when done up. It is quite amazing!

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Miks engineering is so good the thread protector does not even notice when screwed down.

The Jet-Z will add around around 15cm to the barrel and around 560g dependant on your calibre. Certainly not a heavyweight among moderators but not the lightest either. It is definitely one of the smallest rifle moderators in its class (compared against models offering similar noise reduction). This is largely thanks to the patented Jet-Z baffle system being so efficient.

In Use.

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I took the GnZ precision rifle down to a local 100yd range to test performance with the moderator. The rifle is chambered in .260rem which is generally considered to be a little quieter than a .308 but not by much. At around 150db It definitely requires good ear protection. I wear inner foam buds and outer muffs for unmoderated centre fire rifles of any calibre. I used to wear muffs only until I ended up with them riding up a few times leaving me with mild tinnitus (constant buzzing in the ear – not nice).

My main aims would be to assess noise levels, accuracy, ease of use, velocity and point of impact.

The Jet-Z was an absolute breeze to install. Simply unscrew the thread protector on the barrel and screw on the moderator to hand tight.
There are a couple of down sides to all moderators. They get very hot. Like hot enough to fry bacon on. Don’t be that guy who grabs it with your bare hand after your done shooting. Let it cool first.
The heat from a moderator causes mirage in the scope picture. This can be severe in still weather. A little sidewind help as it tends to blow it away from the sight picture. One way around both the burnt hands and mirage is to buy a mirage cover. These are a sheet of heat resistant material which fits around the moderator. Ase produce covers for the Jet-Z range. I did not use a cover. It was a still, cold day so mirage was intense at points but died down quickly if I waited 20-30 seconds. This phenomenon occurs with all moderators and supressors. If you control those hot gasses then you will pick a little heat up along the way.
After shooting had finished I left the Jet-z in place for around 2 minutes before removing it with a gloved hand. It was warm and on such a cold day proved a welcome edition to my frozen fingers.
One of the most welcome side effects of sound moderation is recoil reduction. Although the .260rem recoil is manageable unmoderated, the Jet-Z makes a noticeable difference. Recoil is down to .223 type levels which allows the shooter to stay on target for follow up shots and spot shots landing wide of the mark. I was very impressed as this is the kind of reduction one expects from a muzzle brake without the muzzle brake problems (venting hot gasses at your neighbouring shooters!).

Sound levels.

A video posted by GunsandZen (@gunsandzen) on

The first shot you here is the 6.5×55 next to me. The second is the moderated .260rem.

I set up an app on a tablet to measure decibel readings which unfortunately gave erroneous data. The reading suggested a difference of around 30db which I would think is about right. The readings themselves were both lower than I would expect which caused me to abandon the app completely.
I can only give personal opinion here but I will say I was massively impressed. I had heard people suggest that the .260rem is a “hard gun” to suppress. I found the Jet-Z compact turned a deafening bang into a clap. I wore the muffs only and it quickly became apparent the moderated rifle was well below the pain/danger threshold. It would have been comfortable to shoot with no hearing protection although I would never recommend that.
In short the addition of the Jet-Z compact made a huge difference in noise reduction – excellent. Bear in mind this was the .30cal version which is not perfectly suited to the .260rem but is rated by Ase as being acceptable regards noise reduction.

Velocity/Accuracy/POI shift.

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I ran the rifle over a Chronograph. This is a relatively new barrel with only 70rds through it (Trueflite fitted by Mik at Dolphin Gun Company). I am reserving any firm judgements on velocity as it is likely to change over the next couple of hundred rounds. I was averaging 2950 with 139gr Lapua Scenars. I had an ES of 49 which is not great but is no doubt due to the new barrel. I shot a string of 10. 5 with the Jet-Z on and 5 with it off. Velocity did not differ any more than previous strings with no moderator attached.
Accuracy was not effected negatively. Every string this Trueflite barrel has shot has been phenomenal. The 100yd groups tend to be ragged holes.. No different with the Jet-Z..

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Point of impact was hard to judge at short range. The group posted above was 2 shots with no moderator and 3 with it screwed on. The group is way to tight to call any major change in POI. It will be interesting to repeat the test at 300yds which will open the group up enough to give a better indication. I will sort some longer range testing next time.

The conclusion so far.

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I am extremely impressed with the Jet-Z so far. The size, weight and noise reduction are fantastic with no apparent effect on accuracy. In the follow up I will take the GnZ Rifle out to greater distances so we can look at POI shift properly and continue to Chrono rounds as the barrel settles in. I will also ask Mik at Dolphin to screw cut the barrel on the .308 and then test the moderator on the calibre it is built for! One thing this article demonstrates is that you certainly can save yourself some money and swap the mod between the 6.5mm and 7.62mm barrels just fine.
The Jet-Z compact was sourced from Ase Utra via their English main dealer Jackson rifles. Jackson Specialize in sound moderators (among many other shooting related things) and are well worth a call if you are U.K. based. They sell the Jet-Z compact for £310 which is very reasonable as moderators go. The popular price band seems to be around the £300 mark although there are models which cost a lot more.
Ase give a 2 year warranty with all of their products. I think the Jet-Z will last for many years if it is properly looked after (oiled as per instructions provided).

Links.

Ase Utra – www.aseutra.fi

Jackson Rifles – www.jacksonrifles.com

Dolphin Gun Company –www.dolphinguncompany.co.uk

Hamond rifle – www.hamondrifle.com

Trueflite barrels – www.truefliteriflebarrels.co.nz

MDT (chassis) – http://mdttac.eu

Vortex Optics – www.vortexoptics.com

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