Best Books on Suppressors?
I have been looking for books and drawings, on suppressors. So much of what I have seen is not much more than taping a pop bottle to the end of a barrel.
I am interested in anything good, whether it be history, theory, or design.
Thanks for your help.
I asked this question to a professional gunsmith friend of mine a few years back, and I'll try to remember what I can of the conversation.
Some of the silencers out there primarily scrub enough speed from bullet to make it subsonic, which in turn releases less boom, but also significantly reduces the range of your projectile.
- A baffle type silencer is one easy way to do this. Take a piece of tubing, some metal washers, and a rubber mat. The washers need to be have the same OD as the tubes ID, and the washers ID needs to be much larger than your projectile. Punch the mat into similar washers with the same OD as the tubes ID, but the washers ID to be closer to the OD of your projectile. Stack the washers in your tube, using the steel washers to seperate the rubber. The space between the rubber washers will trap some of the expelled gases and the rubber washers will scrub speed from the bullet to bring it to the subsonic level.
There are other types and materials. This just seems to be the poor mans method.
I don't shoot, never have, probably never will, but if this is of any use to you:
They make it sound like a simple one (for something other than a pistol) isn't that hard to make. Also, not to shoot you down petriej (no pun intended), but that article certainly makes it sound like the subsonic rounds are due to the loading of the cartridge, not the effect of the silencer. Again, I've never shot before, but I certainly think a silencer wouldn't last for too many cycles if it were actually slowing the bullets down from supersonic to subsonic.
I think the idea behind the rubber washers is to trap the expelled gasses (ironic name, no?) behind the bullet, so that there is minimal leakage of high-pressure gas from chamber to chamber, as the bullet passes.
I hope you aren't planning on making one, as this stuff pretty regulated by the ATF, no? As in I certainly wouldn't want to have someone in my shop making unlicensed suppressors (or receivers, for that matter). Then again, i'm a lib, so don't mind me.
A bullet is not actually slowed down. It is kept from reaching supersonic velocity by bleeding off gas, from the barrel, close to the chamber. When we say "slow down", we mean not allowing the bullet to reach supersonic velocity. In other words, a high velocity 22 long rifle round is a supersonic round shot under normal conditions.
Someone correct me if I am wrong. Suppressors that "slow down" a bullet are called integral suppressors and are part of the barrel assemble. It would go around a barrel almost to the chamber. The barrel would have holes, perpendicular to the bore, drilled in it. The holes would start close to the chamber.
A suppressor that is attached to the end of a barrel does not effect velocity. One would have to start with a subsonic round to prevent the sonic boom from the bullet.
A suppressor captures and cools expanding gas generated from the cartridge firing. The cooling of the gas, reduces the "boom", normally generated when the hot gas exits the muzzle of the firearm. There are also acoustic effects of the silencer that have to do with dampening the sound waves, generated by the explosion, of the propellant. Think of it as comparing a room with concrete block walls and concrete floor with a room with carpet, drapes, and sheet rock walls. Or even better, a mud hut. There are more complex acoustic effects but I do not know enough about acoustics to understand it, much less explain it, other than sound waves canceling each other out.
This is my opinion. There are others here that have forgotten more about this subject than I know. Yall please correct me if I am wrong.
Have a great Saturday.
My apologies. I understand how a suppressor integral to a barrel works (at least in theory, by bleeding off gas to reduce chamber and barrel pressure). I assumed you were referring to a screw-on attachment for a standard rifle designed to fire supersonic rounds. In which case we agreed, in that one must start with a subsonic round to avoid the sonic boom.
Now maybe this is silly, but I've always been bothered by the concept of drilling holes in the barrel of a gun. Isn't a bullet in the barrel an mild interference fit, of sorts, with the rifling being negative lands in the otherwise round barrel? The bullet deforms to fit into the barrel, somewhat filling the rifling, which then imparts the spin. If this is in fact the case, then wouldn't drilling holes in the barrel rip pieces of the bullet off, fouling the barrel and damaging the bullet before it even clears the muzzle? Sorry if this is too OT. For someone with no interest in shooting, I'm very intrigued by how it works.
I have the same concerns. The 541T, I mentioned above is built like that. I have concerns about just that. In a handgun or sub-machine gun it probably does not make much difference.
To my understanding, there is a cutter that allows you to but a chamfer on the hole after drilling it. Personally, I do not see how you cannot adversely effect accuracy by drilling holes in the barrel.
I have seen many sub machine guns, 22RFs and handguns built with the integral suppressor.
I would love to hear comments on the effects of drilling holes in the barrel.
There are tons of crap DIY silencer books out there that can get you killed if you follow their directions. Here are the top three books I recommend:
Silencer History & Performance Vol. 1 By Alan Paulson ISBN 0-87364-909-5
Silencer History & Performance Vol. 2 By Alan Paulsen ISBN 978-1-58160-323-1
Firearm Suppressor Patents Vol. 1 by N.R. Parker ISBN 1-58160-460-2
Well the "Magnaport" system cuts ports directly into the barrel and it seems to work ok, has for many years. If I were to port a barrel I would pour it full of molten woods metal first so that my drilled holes left no burr, then I would make my drilled holes hit the grooves not the lands, and finally I would drill a small hole, then "bore" it to size with a very sharp endmill to further reduce any burring. Finally after I had melted the woods metal out I would lap the barrel.
Also every M1 Garand has a hole drilled into the bore, as does every M14 or M14, and every M16/AR-15 as well (unless they are 9mm blowbacks). Some pistols use a gas retarded blowback too. The MP5-SD with built in supressor uses a ported barrel too. Drilling holes into gun barrels is a common thing, done for a variety of reasons.
For plain old 22lr you can just go with a barrel length that ends up providing a subsonic velocity, 3.75" is probably about right, I have one that I made 4" for a threaded on muzzle can (ruger mark III) and it is subsonic with remington bulk golden bullets but not with federal bulk pack ammo, the federal is nicer ammo.
It is probably better to pick a cartridge that is naturally usually subsonic with heavier bullets in a 5" to 6" barrel, one example of that is 45 acp, in that case you do not sacrifice any energy to reduce the bullet velocity to subsonic. 9x19 is also "naturally" subsonic in a pistol length barrel with 147 grain bullets.
There are 'generally' no accuracy issues that directly result from drilling holes in a barrel. Gas operated weapons have had holes dilled for years, integrally suppressed weapons for example the HK MP5-SD have 32 holes drilled forward of the chamber, if you saw one, you'd think the barrel would break off as it looks like seive. Another example is an integral suppressed 10/22 made by Doc Dater of Gemtech, it was the model R10. It had holes drilled ~ 2/3 the length of the barrel and was constructed like a glass pack muffler.
Originally Posted by Grits
All that being said, the cavet is this: The holes have to be properly deburred, if not, they can shave the jacket off the bullet, shave lead in the case of the .22LR. This will affect accuracy and potentially cause other problems.
Some mfrs. take the time to index & rotate the barrel so that the ports are bored between the lands.
Back in the 60's it was legal to fabricate suppressors provided you paid the government their tax. I made several legal suppressors. My "cans" attached to the muzzle.
The body was made from seamless aluminum tubing 1.5" OD X 10" length. In the main, the internal components were fabricated from 80 mesh brass wire washers that were compressed against each other (which I fabricated) and rubber gasket material (actually rubber conveyor belt). End caps were fabricated to a tight slip fit (with a little force). Set screws held the end caps in place. One end was threaded and the other had a hole slightly larger than the projectile. The "can" was rather heavy.
An expansion chamber (approx 2" in length) served to cool gases. This expansion chamber was separated from yet a second but shorter expansion chamber (1.5" in length) by thick gasket material the hole in the gasket material being slightly larger than the projectile. I had a total of 3 expansion chambers each separated from the other by gasket material. Past the expansion chambers were a series of compressed brass screen chambers and four or more rubber baffles (can't remember it's been so long) made of the same gasket material.
Prior to securing the end-cap, a rubber end-wipe (having a hole *smaller* than the projectile) topped off the column and the end-cap fitted and secured by set screws.
My "can" worked quite well and required little maintenance. For maximum suppression, end-wipe replacement was necessary after 8 to 10 rounds.
I loaded slightly below the speed of sound (1080 FPS @ STP).
Sound is a peculiar thing. Sound is heard easier at night and harder to hear during the day. A well fabricated suppressor can significantly reduce sound energy provided the projectile is flying less than the speed of sound. When a round is discharged, they majority of "noise" is from rapid expansion of hot gases. Additional noise can be attributed as mechanical noise when the action cycles. Beyond 1080 @ STP a ballistic crack is easily heard as the projectile breaks the sound barrier however if you are on the receiving end, and though you hear the ballistic crack, it near impossible to determine from where the shot was fired. The more lateral to the discharge you stand the more able you will be to tell direction of the shot. If standing somewhere behind the firing position, you can localize direction with little effort.
Suppressors will also masquerade the sound of a shot. Stated differently, you may in fact hear "a noise" but it won't sound like a gun shot. Differentiation is significantly altered and it may sound like someone dropping a 2X4 plank on a stack of lumber. Even at night, the average person would never realize the noise as a firearm being discharged. Supressors create confusion in several ways.
Choice of caliber is also important. If a .22 were fired through a suppressor and decibels electronically measured, and this measurement was compared with the discharge of a 45 ACP through a suppressor, the .22 would measure significantly quieter than the 45 but to the human ear, the .22 will sound far louder because the human ear is more sensitive to the particular *frequency* produced by the .22 than that produced by the 45 ACP.
So in my opinion, meters and their readings are worthless because in the end, it's the human ear and brain with which we must contend when attempting to suppress the sound of a firearm being discharged. So what if a .22 is twelve times quieter than a 45? Doesn't mean a thing if it's easily heard by a human and recognized as a shot.
That's my 2 cents.
Perfectly legal to make in most states today
It is still legal to make your own suppressors these days if you live in a state that allows for their ownership. You simply need to fill out a an ATF Form 1 (5320.01 I believe is the formal title). This will require a one time $200 tax, CLEO certification, photograph and fingerprints. May also require a citizen certification...you actually certify yourself. Very easy. Hardest part is getting the CLEO, chief law enforcement officer, signature in some places.
Good luck and enjoy the experimenting.
You don't even need CLEO signoff if you form a revocable living trust and then have the trust own the NFA item.
Originally Posted by Fractal
Dig around online. There is at least one forum (silencertalk, IIRC) that is all about the why's and hows, starting with the proper paperwork.
You need to register with a real email address, no webmail. Cuts the number of idiots they have to deal wit, way down.
Everything is legal, as long as the permits are in place before the project starts.
Lots of good info.
Last edited by trevj; 01-03-2009 at 04:27 PM.
Fella I worked for many moons ago manufactured suppressor kits for commercial sale. He said w/ lead bullets, holes bored into the barrel will channel gases across the base of the bullet, cutting the base and screwing up the accuracy big time. Much less an issue in a jacketed bullet. The majority of his kits were screw or clamp on design, but he had some 22 drilled-barrel kits. After drilling the barrel, he reamed the bore to .250 so there was no bullet/bore contact in the ported section. Had to be done carefully-you are effectively re-crowning the barrel at the same time. And, of course, you are also reducing the effective length of the barrel (which is true regardless, once you've ported it).
Re the rubber or urethane wipes at the muzzle end of the suppressor-they are to minimimze the final exit diameter to help retain as much gas as possible. His were urethane, with a hole diameter smaller than the bullet diameter. He said they too played hell w/ accuracy-only used on subgun and some pistol kits. He would never use on rifle kits.
I imagine the wipes would reduce velocity a little, and of course shortening effective barrel length, especially on a pistol, will reduce velocity. But the main way to achieve sub-sonic velocity is w/ sub-sonic loads. They tend to use small loads of fast burning powder, so the burn is, ideally, complete by the time the bullet reaches the suppressor. W/ a lot of pistol and 22 ammo, sub-sonic loads aren't that far from conventional loads. It's pretty tough to get sub-sonic CF rifle rounds that will function a semi-auto or stabilize well.
Just for general forum information, no mfrs use wipes anymore. They most definately affect accuracy as they contact the the projectile and require constant replacement. When Charles 'Mickey' Finn developed & patented the 'K' baffle in '86, it advanced the state of the art significantly, virtually all rimfire cans use a version of the 'K' baffle today. Centerfire suppressors generally use some form of conical baffle, a few lower cost suppressors use an 'M' baffle.
Originally Posted by alaskajeff
There's a good bit of information of subsonic loads for centerfire cartridges but when you're looking at something like a .223, you have a 50gr projectile flying at 1050 fps, verses a 40gr .22LR doing the same. It kinda becomes pointless to use a centerfire cartridge to accomplish the same thing as a low cost rimfire. For a large bore subsonic centerfire projectile, the .300 Whisper is more desirable ballistically. There was a short time where .44 mag rifles were being made in an integrally suppressed weapon. I beileve they were using 300gr projectiles. The problem encountered was a rainbow like trajectory and accuracy issues.
The problem w/ subsonic rifle loads is, as you describe, poor trajectory and low energy in small bore. Also, the twist rate is too slow, unless you use short (light) bullets, so you can't get a stable load and partially compensate for low velocity by loading super heavy bullets. I bet the .44 was a pretty good compromise, though.
Originally Posted by CS223
This thread is almost as good as one I posted several years ago, "Are Snap-On Tools that Good".
I agree with using subsonic ammo, in many applications, to start with. In one of my previous post, I mentioned I was not real happy with my 541T with an integral suppressor. One reason, I prevents me from using any 22LR match ammo. I have to start with ammo that is not that accurate to out of the box.
I have over a case of Winchester LR subsonic hollow points. They are Australian. Around 1990, give or take, Olin offered many of their Australian loads in shotgun and rimfire. I was a Winchester distributor at the time. They closed out all the sku's because they sold the plant. When they did, we had the opportunity to match current inventory at a very low price. I kept a couple of cases of the subsonic hp's and a two or three cases of the Power Points. It is not the same 22LR Power Point they currently offer. Both loads shot very well in my bolt action rifles as well as my 1022. The subsonic Power Point is the best squirrel load I have every used. Unsuppressed, it is pretty quiet and it is some kind of accurate. It is also more effective than a solid lead bullet if you have to take a body shot. I had to hide them to keep them away from my friends.
The 300 Whisper also makes a lot of sense to me. I have a problem with beavers on my rice farm. Not only do they stop everything up, they destroy a lot of timber. Although trapping is, by far, the most effective way to keep them in check, shooting them is fun and it makes me feel better. In my opinion, a 22RF or a subsonic 223 is not near enough gun. At fifty yards, a 220 gr 30 caliber bullet, at any velocity, will do the trick. I do not want to make any more noise in my timber, during deer and/or duck season than I have to.
Sorry for the long post.
Procedure for Applying for Permit to Construct a Suppressor
I am going through the process, of applying for a permit, to construct a suppressor, along with an explosive license.
The information can be found at www.atf.gov. The form is not currently available online but it tells you where to order it. Along with the form and two hundred bucks, you need two photos measuring 2"x2" and fingerprints. The photos are the same as a passport photo.
You also need to complete one copy of the 5330.20 form and include it with the two copies of the the Form 1 and two finger print cards.
Originally Posted by Grits
Explosive license can be a real pain. Especially when it comes to having a storage magazine. Also, check with your state requirements, been a while, pre 9/11, when I looked into it. My state required it's own license at that time in addition to ATF's requirements.