Something odd I have a question about, my can whistles

[Dolomite_Supafly]

I have a Form 1 22lr can that I built. It uses K baffles. It has a large, 1"+ long, blast chamber and the rest of the tube is filled to the end with baffles. It is a BIG can for a 22 lr at 8" long and 1" OD. It is made out of SS throughout and the wall thickness is .065".

Here is the odd thing.

After I clean it the can sounds like it is having baffle strikes on my pistols using subsonic HP rounds, Remington and Winchester. Round nose HV rounds do not seem to do it either or at least not as bad. It makes a very high pitched whistle that seems to echo back at me from a tree line I shoot into. It drove me crazy at first because I thought it was a baffle strike but the gun shoots to point of aim, even at long distances. It is not a riccochet either because I can get a few hundred yards before the bullet strikes anything and even then I get the high pitched whistle.

It only happens on pistols. I have a threaded 22/45 and single shot Cricket pistol I threaded for my can. When shooting into the ground the can is VERY quiet regardless of the platform. It is also very quiet on a rifle using subsonics, my dedicated AR is action noise only.

What is odd is the whistle is there until I add some wire pulling gel to the can then the whistle goes away. It stays away even after the gel is gone but after the can is dirty.

Another oddity is both pistols I use my can on stabilize the SSS rounds enough to get them out of the can. And when firing them there is not a whistle at all, just a thud.

Not really sure what might be causing it but ideas on how to fix it would be great. It is a very, very quiet can otherwise. Maybe the cure is to just not clean it as often. Right now I clean it about every every month. And it isn't THAT dirty when I do.

Dolomite

[alemonkey]

Maybe there's a pinhole or a leak somewhere that fouling or wire pulling gel blocks? Could you pressurize it somehow and submerge it in water to check?

[Historian]

Reminds me of the 1945 (?) movie with Humphrey Bogart and
Lauren Bacall on how to whistle: "Put your lips together and blow".
<< http://www.youtube.com/watch?v=hrUsfyVmeKg >>

Ehow.com has a good explanation of the mechanism of whistling:

" The Whistle
Whistles can be made of a hard material, such as plastic, wood or metal.
It is a device that makes a whistling sound when air is blown through its mouthpiece.
One type of whistle is similar to a hollow tube, where one end is open and used as the mouthpiece.
On the side of the whistle is a sharp edge that creates a slit or opening along the midsection.
When air is blown into the opening, it strikes the edge which sends the air whirling.
This motion compresses and then expands the air.
That creates vibrations and makes the trademark whistling sound."

You may wish to remove any sharp edges and the observation that the whistling varies with arms
further suggests that if you have a baffle design you should vary the spacer widths to stop resonance, much
as putting dampers on high tension lines to keep them from setting up destructive vibrations in high winds.

My first guess.

[Dolomite_Supafly]

Reminds me of the 1945 (?) movie with Humphrey Bogart and
Lauren Bacall on how to whistle: "Put your lips together and blow".
<< http://www.youtube.com/watch?v=hrUsfyVmeKg >>

Ehow.com has a good explanation of the mechanism of whistling:

" The Whistle
Whistles can be made of a hard material, such as plastic, wood or metal.
It is a device that makes a whistling sound when air is blown through its mouthpiece.
One type of whistle is similar to a hollow tube, where one end is open and used as the mouthpiece.
On the side of the whistle is a sharp edge that creates a slit or opening along the midsection.
When air is blown into the opening, it strikes the edge which sends the air whirling.
This motion compresses and then expands the air.
That creates vibrations and makes the trademark whistling sound."

You may wish to remove any sharp edges and the observation that the whistling varies with arms
further suggests that if you have a baffle design you should vary the spacer widths to stop resonance, much
as putting dampers on high tension lines to keep them from setting up destructive vibrations in high winds.

My first guess.

You guys are amazing.

I went back and thought to myself what did I change before it started happening. The last time I cleaned it I decided to make it "pretty" and squared the edge of the exit hole up. Before that the hole was chamferred.

I cleaned the can completely then chamferred the hole on the inside and outside. I went and shot it and the whistle is completely gone.

Thanks guys
Dolomite

[Enfield577]

Reminds me of the 1945 (?) movie with Humphrey Bogart and
Lauren Bacall on how to whistle: "Put your lips together and blow".
<< http://www.youtube.com/watch?v=hrUsfyVmeKg >>

Ehow.com has a good explanation of the mechanism of whistling:

" The Whistle
Whistles can be made of a hard material, such as plastic, wood or metal.
It is a device that makes a whistling sound when air is blown through its mouthpiece.
One type of whistle is similar to a hollow tube, where one end is open and used as the mouthpiece.
On the side of the whistle is a sharp edge that creates a slit or opening along the midsection.
When air is blown into the opening, it strikes the edge which sends the air whirling.
This motion compresses and then expands the air.
That creates vibrations and makes the trademark whistling sound."

You may wish to remove any sharp edges and the observation that the whistling varies with arms
further suggests that if you have a baffle design you should vary the spacer widths to stop resonance, much
as putting dampers on high tension lines to keep them from setting up destructive vibrations in high winds.

My first guess.

Good effort that man - I am impressed

[Bendersquint]

We made a can with a ridiculously tight bore and it whistled every shot, actually made the near identical noise to the Hollywood silencer shot. Turned out it was so tight that the bore was shaving some of the bullet off as we found lead shavings in the tube after, point of aim point of impact out to 100 yards. Was really weird, opened the bore just a smidgen and never heard it again.

Had a guy in the background saying "Holy Crap he has a Hollywood silencer" I chuckled!

[LavaRed]

We made a can with a ridiculously tight bore and it whistled every shot, actually made the near identical noise to the Hollywood silencer shot. Turned out it was so tight that the bore was shaving some of the bullet off as we found lead shavings in the tube after, point of aim point of impact out to 100 yards. Was really weird, opened the bore just a smidgen and never heard it again.

Had a guy in the background saying "Holy Crap he has a Hollywood silencer" I chuckled!

I've been trying to get that Hollywood silencer sound for years. Never thought squaring the interior endcap and tightening the bore might help. I'm off to try that now!

[Bendersquint]

We made a can with a ridiculously tight bore and it whistled every shot, actually made the near identical noise to the Hollywood silencer shot. Turned out it was so tight that the bore was shaving some of the bullet off as we found lead shavings in the tube after, point of aim point of impact out to 100 yards. Was really weird, opened the bore just a smidgen and never heard it again.

Had a guy in the background saying "Holy Crap he has a Hollywood silencer" I chuckled!

I've been trying to get that Hollywood silencer sound for years. Never thought squaring the interior endcap and tightening the bore might help. I'm off to try that now!

The tight bore made baffle strikes which created thw whistle as the bullet tumbled down range.

You don't want to know how tight that bore was!

[LavaRed]

We made a can with a ridiculously tight bore and it whistled every shot, actually made the near identical noise to the Hollywood silencer shot. Turned out it was so tight that the bore was shaving some of the bullet off as we found lead shavings in the tube after, point of aim point of impact out to 100 yards. Was really weird, opened the bore just a smidgen and never heard it again.

Had a guy in the background saying "Holy Crap he has a Hollywood silencer" I chuckled!

I've been trying to get that Hollywood silencer sound for years. Never thought squaring the interior endcap and tightening the bore might help. I'm off to try that now!

The tight bore made baffle strikes which created thw whistle as the bullet tumbled down range.

You don't want to know how tight that bore was!

Oh ok. I thought it was the tightness of the bore making the baffles vibrate.
How tight was it? I mean, I normally do exactly 1/4" on my .22LR ones; I can't really imagine how much tighter you can go?

[Enfield577]

Brings a whole new meaning to tuning a can

[RPM509]

This just goes to show, you can tune a piano and you can tuna fish, but you can't tune a can!

[Bendersquint]

This just goes to show, you can tune a piano and you can tuna fish, but you can't tune a can!

nicely put.

[Trex]

very good, Historian.

[mollinst]

Jeez Trex, will you please change your avatar? I just came-to after being unconscious for about 20 minutes.

[Historian]

This just goes to show, you can tune a piano and you can tuna fish, but you can't tune a can!

Holy MACKEREL!
Bravo! Clever! I have finally met my match.

My compliments, sir.

What the HAKE, HADDOCK been more
alert I would not be FLOUNDERing to catch up in embarrassment
in not PERCHING on this perfect opporTUNAty to have
punned first.

O.K. I shall stop CARPing before our brethren here
HARENG me.

I graciously raise the next glass of brew to you in honor of your win.

Best.