posted March 07, 2000 01:27 PM         

All 22LR ammo will give silent firing in this design, so expensive subsonic ammo is not needed.

All 22LR ammo is designed to work also in 22 pistols with 2 inch barrel length. All brands reach about the same subsonic velocity with the 2 inch barrel length. Test what you intend to use. Hyper vel also exits subsonic, from a 2 inch bbl. for it gains most of its hyper speed in the longer 16 to 20 inch barrels.

This forum lists no limit on post length, and since it is an international forum, although the machine may have one of its own, which I will discover.

This discusses, how, in detail, and also xplains why things are done, to silence a 22 rifle or pistol, because the technology is poorly understood, and because such weapons
are fully legal in most of the world. They are a great benefit in hunting small game for you can shoot several times if you miss before an animal catches on that the zip
it hears of the bullet passing is not an insect. Most never catch on.

To silence a bullet you must reduce its velocity below the speed of sound. That speed varies with air temperature, being lowest in cold air. A speed of 1000 fps will work in
cold well below zero F. 1000 fps keeps enough energy in the standard 43 grain 22LR bullet to get the job done for skull penetrating head shots out to 75 yards maybe 100 yards.

If the weapon is an autoloader, the limit on how quiet you
can make it is limited by the noise the bolt makes in
reloading. No point in doing better than that.

Another limit on quieting the bullet is the noise it makes when it exits the silencer and rips through the air at sub sonic velocity. That sound rises greatly as its speed gets
close to mach 1 (speed of sound) and at that speed an enormous increase takes place as the shock wave forms and compresses air to very high pressures, creating a noise almost as loud as the blast from an unsilenced gun. This can be tested by firing a gun straight up from on top of a building or hill so nothing above can reflect the shock wave
back down. The normal 22 with bang and crack is much quieter when thus fired, and the up close crack is absent.

A traveling bullet makes a zipping sound. This is similar to a fly rod whipping through the air when you do it fast. The bullet passes you so fast, all you hear is the sound it makes when it is within about 10 feet of you, which is a pop that lasts about 1/50th of a second. This is for a subsonic bullet. For a hypersonic bullet you hear a much shorter and louder snap that sounds like a single spark of a very large stun gun.

Animals hear this pop of a subsonic bullet, and cannot locate on it because it is both in front of and behind them. They usually freeze and wonder about it. If a muzzle blast
occurs, as from a unsilenced weapon, they locate and recognize that pronto, and flee. The distant puff of a silencer is not recognized by them and they do not flee,
although their ears are plenty good enough to hear it, and locate it.

A 22LR bullet begins accelerating down the barrel when the primer blasts it loose, and the power then starts to burn, and accelerates it so fast that by the time it is about 2 inches from where it started it is traveling around 1000 fps. That is why 2 inch barrel derringer pistols shoot 22LR ammo with plenty of effectiveness.

If the barrel is longer than 2 inches, the powder continues to burn and accelerate the bullet, until max velocity is reached in about 16 inches. If the barrel is longer than
that the bullet slows down some as it continues because of barrel friction exceeding the push from the powder.

If noise is no object, a 16 inch barrel will usually give max velocity to a 22LR. The muzzle blast will be great though because the exit pressure of the powder gasses will
be high, around several thousand PSI.

To stop acceleration at about 1000 fps, cut the barrel off at 2 inches from the bolt face, or drill holes in the barrel at that distance to drop the pressure on the powder which will stop it burning. The unburned powder will go into the silencer and remain there as little yellow flakes of uncoated smokeless powder. This will sometimes catch fire in a heavily used silencer, and cause a flame to exit it as the powder burns off. The pressure seldom gets high enough to make much noise doing this, and the exit holes in the
silencer prevents pressure rising high enough to burst the silencer, because smokeless powder burns slowly unless it is under great pressure.

If you leave more barrel than 2 inches, then at the 2 inch distance from the bolt face, drill 1/8 inch holes through one side of the barrel, passing through the center of the
bore, and out the other side. Now put a number 1 drill in the barrel as a stop for your countersink drill. With a .25
inch drill, countersink the 1/8 inch holes inward from each outside end until the tip of the .25 drill hits the drill in the bore, and stops its depth.

Do the same at 90 degrees from this first pair of holes so you end up with 4 holes in the barrel. It is best to make the second pair of holes about half inch further down the barrel (at the 2.5 inch distance, so you don't weaken the stiffness of the barrel too much with all the metal you remove in the same place if all holes were at the same
distance.

The barrel ought not go much more than about 4 inches past the first pair of holes making the whole barrel no longer than 6 inches.

This added length is mostly to allow the silencer to have
better bracing, and thus be more immune from being bent if
dropped.

The 1/8 inch holes drilled into the bore have sharp edges inside the bore. These must be rounded off using a 1/8 inch spherical tipped cutter in a Dremel or drill press tool.
Insert the ball through the countersunk hole into the bore, and wobble it around the inside so the ball's underside (nearest the drill chuck) rounds the edges of the 1/8 hole
(inside the bore) using its rear cutter faces. Round all holes penetrating into the bore so you don't shave bullets as they pass by.

Next find a 1 foot long piece of the drain pipe used on kitchen sinks. It is made of chrome plated brass and has an outside diameter of 1.5 inches. You can use the PVC pipe type instead of brass if you only intend to shoot the gun no more than about 10 times between letting the silencer cool down. Do it more on PVC and you may soften it and the bullet may begin hitting the exit hole. That makes it useless except at about 10 ft range, because the bullet will go wild if ANYTHING touches it.

Older silencers that used "wipes" which the bullet squeezed through, because ignorant makers thought that gave a quieter silencer, were useless at normal shooting ranges, because the bullets went wild.

You must make metal washers of a diameter to snug fit inside the pipe you use. One metal washer is soldered square on the barrel behind the first pair of holes. How far is
irrelevant, and can be done to satisfy whatever is back there that would be in the way. Lead Solder will hold except in full auto fire of several dozen rounds which would heat the barrel above about 500 F. If you intend to do that silver solder the washer there.

Then go to the end of the barrel, and put another washer square (perpendicular) there, soldered or brazed.

These two washers must be a snug fit to the inside of your pipe for they align it. Put the pipe over the barrel washers with about 1/16 inch sticking past the first rear washer. Solder the outer rim of the washer to the pipe. If PVC, use epoxy or bondo to seal this.

Next solder or seal the outer rim of the washer at the barrel end, which will be well down inside the silencer tube.

Next, slide down into the silencer a tube which snugly fits inside the outer silencer tube. This can be made of PVC, or of the brass pipe, with a slit cut out lengthwise so it will squeeze down to slide inside the silencer pipe. It needs to be 2 inches long. Slide this spacer pipe inside the silencer
till it hits the washer on the barrel end.

Next, using a washer that has an outside diameter snug fit to the inside of the silencer tube, and a center hole of
5/16 inch, push it down against the spacer just installed. Seal this washer to the outside pipe by soldering, or if the
outer pipe is PVC, use epoxy or bondo.

Do the same with more spacers and washers until you have a distance of less than 2 inches from the last installed washer and the end of the silencer pipe. Longer is quieter,
but beyond 18 inches gains little.

The last washer must be made of innertube rubber. To install it, cut a 2 inch square piece of rubber, and put crazy glue
on the entire rim of the end of the silencer tube, and press the tube against the rubber (washed to remove the coating, and dried) and hold it till the glue sets.

Next using scissors cut the rubber flush with the edge of the silencer tube so none sticks past the tube circumference. For added quietness slip bicycle innertube over the outside of the silencer to soak up the ping the gas entering the first chamber makes. Also crazy glue the front of this innertube to the rubber washer edges at the silencer
front, to give it more strength against loosening from repeated puffing out with each shot.

Next, load the gun with a 22LR which has had the bullet cut with a razor so it is flat, and only about 1/16 inch of it sticks out of the brass hull. Do this by rolling the bullet
as you apply pressure to the razor blade and it will cut a circle around the rolling bullet to the center. It is now a flat punch, and fired through the silencer with held with
its rubber washer flat against a plank, it will punch a hole where the bullet exits.

Next, take a hot soldering iron, and open the diameter of this .22 hole to about .3 inches, centered on its original center, by burning the rubber as the soldering iron tip is
slowly forced into the .22 hole. The tip ought not go past the point where it is .3 inches diameter. If the tip is smaller, burn the hole to .3 by going around its inside.

The reason for the last washer being flexible rubber is that a bullet passing through an orifice hole causes a pop like a piston and if the hole is flexible it bulges some and the noise is less. It can be louder than the
bolt action noise if a .25 hole and stiff metal washer is used.

In the first chamber where the gas from the barrel holes enters the silencer, some small advantage can be gained by partly filling the chamber with copper brillo pot scrubbing
pad mesh or with copper wool (similar to steel wool), or with fine aluminum lathe turnings. The mesh absorbs some heat, and reduces the hot gas pressure some, but if you pack the chamber with it, the loss in expansion volume will defeat its purpose. Wool loosely fitted into the chamber is
best.

This will give a very quiet gun. If more quiet is needed, an extension of about 8 inches can be made that will slip over
the end of the silencer, (standard drain pipe has these slip on ends) and that slip over extension needs to have glued to its inside surface (but not in the part that slips over the silencer) ordinary rug which will soak up the noise of the exit pop. This slip over addition can be made from a roll of rug, with no pipe if it is sewn or glued so it will stay on ok.

The quietest gun will be a bolt action or an auto that has locked bolt. The unlocked auto will be considerably louder. To see how much, work the action and see how far a friend can hear it clacking. A well silenced bolt action makes a ping noise and its mostly from the hammer falling and spring singing. It will not be much louder than dry firing the gun.

The bullet makes a zip sound, at the target, as it passes, if it misses. A hit makes a sound like a hammer driving a nail in a board, which is LOUD. It is at the target though, and no direction can be determined. The shooter can easily tell if he hit home by the loud sound of the bullet striking
target material. Meat makes a Ploop sound, skull makes a pop sound, about the same as hitting a tree.

As long as no part of the silencer touches the bullet, only
the last inch of the barrel determines where the bullet
strikes. If you cut the barrel off, do chamfer the end of
the bore, but keep it perpendicular so the gas does not
cause a side push to the back of the bullet that clears the
end last.

A scope mounted on the silencer, over the first two washers of the barrel will remove movement caused by temperature changes. The end of the silencer will move as it heats up,
so don't expect a scope further down on it to have much accuracy for 2nd or 3rd shots, etc. It takes perfect symmetry for this movement not to be partially perpendicular to the bore. This is hard to get which is why the washers have good clearance to a .22 bullet. Also the bullet seldom leaves the bore going straight, for the bore does not stay in the center of the barrel, but wanders as its drilled. Close to the bolt face though it tends to be pretty well in the center.

A scope on the receiver frame is ok also because the barrel is so short you don't have to worry about barrel droop or wander with temp. ALL barrels wander some with temp rise.
Only a long eye relief pistol scope mounted on the barrel end is immune to this source of sighting error. Even the 2" or 6" barrel will move some, but 22LR is not accurate to more than about 2 to 4 inches diameter at 100 yards, in non target guns. 100 yards is the limit on usefulness of a 1000 exit fps 22LR. 75 is better, and 50 is quite deadly.

Many designers have stuck this or that in the expansion chambers, between washers in the silencer, but the gain is usually not all that much except in high powered rifle
silencers where the exit volume of gas is much greater (like 10 to 15 times more) than 22LR. In the 22 silencer the gain is trivial on all designs tested.

It is possible to do all this entirely in PVC, by using fittings and bondo to make the fittings fit the barrel, and using standard metal washers. The larger hole in say 3/8
washers with OD to fit the silencer tube (or close to it) can be bondo sealed while centered, and work. The PVC silencer will be ok for firing where the shots are spaced so
as not to overheat the tube. Cooling can be speeded up by leaving the bolt open and letting cool air chimney through the upright silencer.

The 12 inch silencer length is about as short as can be really quiet. So a silent gun can not be much less than about 14 inches barrel length, and whatever length for the bolt mechanism and whatever length the stock is. Most end up a tad over 2 ft long overall. Pistols end up the same less the stock length. 22 revolvers cannot be silenced very well because the gasses exiting the gap in front of the cylinder are about 10,000 or more psi, and make a fierce noise.

So now you have more info on 22 silencers than most folks have who are making them commercially.

To really top it off, you can glue a cheap laser to the silencer tube, after pointing it so it shines where the bullet hits, say at 25 yards. Put it on top, and it will be about .7 inch above bore, and be close enough to just point and shoot up to 25 yards, on small game, in dim light. How to do that was in another post.

If you use night vision, the ONLY way you can aim the gun is to use a laser, unless you have a night vision scope mounted on the gun. Hard to walk at night using a scope NV to see
where you are going.

Scope NV sight means more bucks for helmet NV to walk with. It's easier to laser the weapon, and NV the helmet only. Use IR lasers from old CD players if you have the patience to use the lenses that come with it to make it into a spot projecting laser. They are not very visible to eyes without NV, even looking right into them. The spot they project is
invisible to eyes, as are they from the side. The spot has to pretty well shine into the eyeball to see them from a distance. Those are 730 nm lasers. The cheap 670 red lasers
have sold at big lots recently for $3 each. They can work as is on 22lr for the recoil is trivial. They require internal work to use on larger guns.

posted March 09, 2000 08:09 AM         

explain why can't you cut a barrel off 2 inches from a bolt face?

why do you say one should not drill holes in guns? All mfgrs do it. The biggest hole they drill is the bore.

For your information several silencers as described above are now in use by covert forces worldwide. They will fire ANY 22 rimfire ammo, quietly.

Your comments need explanation. Their short print version of a sound bite, gives them dual meaning. Do you mean the post info is from an unexperienced source, or do you mean you are unexperienced at doing the simple machining operations it discusses?

If you could be more specific perhaps the uncertainty can be clarified, to the benefit of fourum members.

posted March 11, 2000 05:30 AM         

Those who want pretty guns which can be shifted to silent mode now and then will learn too late that such guns have poor accuracy, because each time you attach anything to the bbl it changes the bullet's point of impact.

Thats ok for plinking, but not for the things silent weapons are usually used for.

If you want a covert looking silencer, use a marlin 39A which has a very long bbl, and drill the front 4 inches of the bore out to diameter .5 inch, and put into the end of the .5 hole a steel plug about .3 inches long and drilled to .25" dia exit hole, and solder it in. Use only 22LR std vel, and the noise will be about that of a BB cap. It will not be as low as really good silencers, but it will be very hard to detect by casual observers. You can say you are shooting OLD ammo if someone at a range asks what the hell you are shooting, for there will only be a putt...splat as gun fires and then the bullet hits the 100 yard target. Folks will ask, so have a story ready or great suspicion will arise. A handful of bb caps would be good cover explanation.

If you want a mfg silent gun, go to that fellow in Titusville Fla, who advts in shotgun news. He makes them from Ruger guns
and they are good. That way you can have a pretty gun, and one that costs a great deal, and one that is licensed, and one that cannot be taken across any state line without prior approval of ATF, and one that requires special ammo, that is traceable with very little trouble.

As for that 60 grain 22 sub sonic ammo, its a new fad. The difference in that traceable ammo and ordinary 22LR stuff is only 50% more muzzle energy, at the best, which is not worth the trouble. 2 rounds of the common stuff beats it.

There are many silencers, and they vary in their quietness as much as do car mufflers.
They all change the sighting of the gun, and that varies each time it's attached. Whether these problems affect you depends on what accuracy you are trying for.

However the other designs posted as replys are OK for they give the forum thread alternative choices to suit whatever the reader is looking for. If you life is going to depend on the weapon though, mickey mouse designs are not a good choice.

Above all, test the thing before you commit yourself to using it. Get to know it very well. Get to trust it. With the world situation flaming up as it is, you may have to use such a weapon when governments are no longer functioning, and it will be equally illegal to have any weapon as it now is to have a silent one in the USA. Getting shot on sight with a weapon is common in areas of great political turmoil, where one illegal power is trying forcibly to oust another.