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StevieLaner7777 · Moderator

Hi all

Recently I have been very interested in making my own suppressor for my 1077, But I'm not too sure on what dimensions I should use to make an effective suppressor, I have decided to make it out of Steel so I can hot blue it properly, Though it might be a bit heavier than Alu that I originally planned to make it out of.

As some of you might know that I already have a suppressor attached to my 1077, But this suppressor only consists of just one expansion chamber and nothing else, So I am interested in making a suppressor that consists of 4 to 6 horizontally positioned cylindrical expansion chambers within the vertical suppressor tube (I will post up an Image of what I mean ASAP).

After a few evenings of researching on various sites and forums, I have found out that most suppressors have a volume of 30 to 40 times more than the barrel, But these measurements are only relevant to powder burner suppressors as of the heat that is also produced as well as the gas, So I don't think that the inner volume will have to be as large for a CO2 Air Rifle, So I'm a bit unsure of the dimensions used to make an effective suppressor.

Any opinions, help or advise would be greatly appreciated.

Stevie Thumb Up!

AirGunEric · Site Admin

Alstone is likely the resident expert on suppressors.

That being said- if your research is correct and on most powderburners a suppressor's internal volume is 30 to 40 times that of the barrel- I might suggest a fair bit less would be required on a sub-sonic airgun. On a powderburner- heat is generated from the gunpowder itself as well as the air compressed in front of the projectile. So, an airgun going well under subsonic speeds (let's say 800fps just to be nice) compared to a powderburner likely going 2-3 times that fast, or two to three times the air expansion plus the heat expansion due to the gunpowder which won't be present in an airgun- we can estimate that for an airgun silencer that volume of barrel to volume of suppressor is probably more like 10-15:1.

Of course volume isn't the only issue, and while again, not as critical to an airgun- heat dissipation and the ability to "wipe" or "scrub" the gases away from the projectile as it travels through the suppressor and after it is out the muzzle. Heat dissipation is not very efficient with steel or iron- much better with aluminum. If you're using steel, I might suspect you would need slightly more volume than if using aluminum- assuming of course the heat produced by an 800fps gun is even worth talking about. As for the "wipe" effect- that is dependent on the chamber opening design and/or actual synthetic "wipes" that are replaceable that actually wipe the projectile as it passes through. On a lower-powered airgun, actual "wipes" are likely only going to reduce the pellet velocity a fair bit- so the chamber opening/shape design is probably alot more efficient from a performance of gun vs. performance of suppressor point of view.

I'm no expert on suppressors- so if something I've posted is inapplicable or a bit 'off'- let me know. Hopefully Al can add some useful stuff- he's built at least a couple airgun suppressors.

Alstone · Moderator & Site Supporter

Hi Stevie
I have built many silencers over the years and you can use most material's provided it is strong enough and rigid, It also depends on the output of the gun the higher the power the bigger the silencer, airgun silencers can be a lot simpler than one's for firearms. the volume of the silencer needs to be at least 20 times the volume of the barrel, make the first chamber take up half the volume of the tube then divide the rest up with baffles, not to many, depending on the power of the gun between 3 to 6, I would think 3 should be enough for your project, the length of the tube makes more difference than diameter, about 5" long and 1" dia should suffice, also make sure that the fixing to the end of the barrel is a good fit with no movement at all, for 177 cal the clearence hole can be up to 6mm and for 220 cal it can be 7mm don't make the clearence to tight or it will affect the flight of the pellet.

The use of wipers and replaceable baffles are not required under about 800 ftp if at all.

Make the silencer as an empty tube to start, you need a removeable end plug at the front, try it out empty to start with then add baffles as required,using discs and thin wall tube as a seperater, this can be plastic.

Don't believe all that you read about silencers for air guns, most of the people who post articles on airgun silencers are basing there knowledge on powder burners, and airguns are a diffrent kettle of fish completely, they are very simple to make and can be very efficent, there is no heat if you are using Co2, no residue and low pressure under about 10fpe, compared with powder burners.

AL

Alstone · Moderator & Site Supporter

By the way Stevie I look forward to seeing your "Blued" silencer, bluing is not easy especialy on large objects, if it was me I would send it to a good parkerizing company, but good luck anyway and and if you crack it let us all know the secret.

AL

leadman · Veteran Member

i have never built a suppressor as it would be illegal for me to do but IF i were to build one i would wrap hair currlers in brillo pads *forming another tube* and stick that in the suppressor to adsorb more sound. i may be wrong in that thinking but it makes sence to me

Eric

StevieLaner7777 · Moderator

Hi Al

I can assure you that I will be taking plenty of photos throughout the designing and constructing stages of the process and of course lots of pics of the finished result.

I'm not too sure yet on taking the suppressor to a "Parkerizing" company, Though this will be an option when I get to the Bluing stage.

And Lastly in response to Leadman's post:
I'm not sure about wrapping hair curlers in Brillo pads, But the other alternative to this would be to use steel wool in the main expansion chamber, This will muffle the sound a bit more and it might even help towards heat dissipation.

Stevie Thumb Up!

P.s. I will be posting up the dimensions that I will be deciding on by tomorrow (Sat).

Alstone · Moderator & Site Supporter

The whole idea of a suppressor is to catch as much of the hi-speed gas as possible and let it out slowly, if you fill the tube with sound deadening material it does work, but reduces the total area if you left the tube empty you would have more volume for the gases to expand, it's six of one and half a dozen of the other. The only time that it pays to fill a suppressor with sound absorbing material is on powder burners where there is very high pressure and the gas is forced into the material, with airguns the pressures are not really high enough to work properly.

AL

StevieLaner7777 · Moderator

Hi Al

OK then! I will keep that in mind, Thanks for the advise on that Al.

Also here is an image of what I was trying to explain in the first post on Suppressor design:

Sorry about the image, I couldn't find this suppressor on the net so I had to take a photo of my magazine!

I don't think I will be making my first Suppressor on this design, But maybe as a V2 or V3.

Stevie Thumb Up!

Alstone · Moderator & Site Supporter

Hi stevie suppressors are so simple for airguns that manufacturers have to think of new ways to make them look "Super Duper", the one in the photo is a very bad design, the idea is to get the gas away from the pellet and hold it back, the way the holes are cut across the tube the gas will expand behind the pellet as it passes through the cross cut hole pass the pellet and meet it as it reaches the next hole causing unwanted vortexs, also about 20% of the tube is taken up with the inner tube, which means less room for gas to expand.
Another thing to remember is that springers compress the air when you pull the trigger, compressing air makes it hot thats why you sometimes you get dieseling, Co2 is already compressed in a capsul and when you pull the trigger it expands, expanding gas freeze's so no heat to bother about.

Buy the way whats a V2 or V3.

AL

StevieLaner7777 · Moderator

Hi Al

OK, After some thinking and looking around the "work shop" for the materials to make it (30mm steel rod), I have decided to make quite a large suppressor to maximise the suppression, So here are the measurements that I have decided on so far, 30mm OD by 200mm in length, I have decided to make this Suppressor noticeably longer than most Airgun Suppressors as I feel that the 1077's barrel length is out of proportion with the rest of the rifle (short) and I quite like the look of a long suppressors. I do realise that this will throw the weight of the rifle forwards especially as I will be using steel and not alu for the construction, But I only shoot whilst laying on the ground or whilst shooting from a bench with a Bi-pod of course.

Q: Can you or anyone else give me any suggestions to how thick to make the tube of the silencer? I'm trying to keep the weight to a minimum, yet still strong enough so it won't dent.

Lastly, 'V2' or 'V3' usually means a second or third version of the original design.

Stevie Thumb Up!

AirGunEric · Site Admin

Back to the "V2" and "V3"- what was different in those versions as compared to the one you posted?

Alstone · Moderator & Site Supporter

Hi Stevie 1mm wall thickness tube will be alright, you could getaway with .5mm but depending on the quality it might dent easily.

I see what you mean with V2, V3

Working on the dimensions 30x200mm all you will need is one baffle in the middle and all you will hear is a click when you pull the trigger,

AL

StevieLaner7777 · Moderator

Hi AirGunEric

OK, I may have confused some people with this 'V2', 'V3' stuff, But what I mean is that I will probably be making more than just one suppressor after the first one has been made, The first design "V1" was to make the 'cross-cut' design that you can see in the image that I posted above, This design was later scrapped after Al's comment of the major flaws in the 'cross-cut' design causing uneven vortexes and leakage between the inner structure and the outer tube, So on came the 'V2' Design which is to make a simple tube with two evenly sized large expansion chambers, the primary expansion chamber will be left completely empty, But the secondary expansion chamber will be divided by ~ three evenly spaced baffles before the unscrewable end cap at the front of the suppressor.
As for 'V3', At the moment the designs for this is non existent, But after V2 has been made and tested I will start thinking about what I want to improve from V2 to make V3.

Stevie Thumb Up!

AirGunEric · Site Admin

Oh, I see- the "V2", "V3" are the designations of your own units. But, don't you actually have build each version to have a "V1", "V2", etc. ?

Otherwise all you have is "P1", "P2", "P3" etc. - 'P' as in "Plan". Razz

Alstone · Moderator & Site Supporter

Or you could finish up with Mk1, MK2, MK3 etc.

AL