First, let me say I have no useful knowledge of suppressors, nor am I able to own one in my over-regulated state. But I am concerned about noise.

I have a place to shoot recreationally as well as hunt, but I am required to be somewhat "discreet" -- how noisy and when I'm making it are key concerns.

I have done some tinkering with CF subsonic rifle rounds over the years and am encouraged with relative quietness. Since I can't own a suppressor, I have gotten all I can get out of barrel length, powder selection, and velocity variables.

Now I've seen something many of you might know about:
"Krinkov" Flash Hider by JNRifleworks
It seems that the basic principle of operation isn't so much to suppress sound as to "direct" it. The device reminds me of the cone-style (non-electronic) megaphone, wherein the sound energy is "pointed" rather than allowed to dissipate spherically. If you stand next to someone using one of these old megaphones, his voice actually seems muffled. To people in the path of the cone, it seems amplified. I'm guessing that's what's going on here.

The inventor says ATF has no problem as there is no "suppression" per se.

For the locale in which I'm shooting, if I could "direct" the noise in the muzzle "cone" it would make a BIG difference to the neighbors. The direction of shots is toward downward-sloping, heavily wooded terrain.

Anyone able to help here, both with the physical principles involved and the regulatory concerns about suppressors? I'd also like to know how the "fake cans" effect muzzle blast. I know there are no baffles inside (otherwise you end up in the Federal pound-me-in-the-etc. prison), but it seems that you still have an expansion chamber and then restrict the gas flow out of a bore-sized orifice, which would make a noticeable difference, baffles or not.

Uneducated comments are welcome as well -- I'm an uneducated questioner.

Muzzle devices that redirect sound are legal, while anything that reduces sound is restricted.

If a fake silencer reduces the sound ANY at all, it is classified as an NFA sound suppressor. That's why the XM177 moderators (which only slightly reduce the sound by a few decibels) are considered NFA.

NRA highpower shooters have been using bloop tubes for years(albeit to lengthen the sight radius).  they got that name for a reason.....ie..... big expansion chamber that also probably redirects the sound.  

Quoted: NRA highpower shooters have been using bloop tubes for years(albeit to lengthen the sight radius).  they got that name for a reason.....ie..... big expansion chamber that also probably redirects the sound.

And they are about half a cunt hair from being declared suppressors.

Quoted: First, let me say I have no useful knowledge of suppressors, nor am I able to own one in my over-regulated state. But I am concerned about noise. I have a place to shoot recreationally as well as hunt, but I am required to be somewhat "discreet" -- how noisy and when I'm making it are key concerns. I have done some tinkering with CF subsonic rifle rounds over the years and am encouraged with relative quietness. Since I can't own a suppressor, I have gotten all I can get out of barrel length, powder selection, and velocity variables. Now I've seen something many of you might know about: "Krinkov" Flash Hider by JNRifleworks It seems that the basic principle of operation isn't so much to suppress sound as to "direct" it. The device reminds me of the cone-style (non-electronic) megaphone, wherein the sound energy is "pointed" rather than allowed to dissipate spherically. If you stand next to someone using one of these old megaphones, his voice actually seems muffled. To people in the path of the cone, it seems amplified. I'm guessing that's what's going on here. The inventor says ATF has no problem as there is no "suppression" per se. For the locale in which I'm shooting, if I could "direct" the noise in the muzzle "cone" it would make a BIG difference to the neighbors. The direction of shots is toward downward-sloping, heavily wooded terrain. Anyone able to help here, both with the physical principles involved and the regulatory concerns about suppressors? I'd also like to know how the "fake cans" effect muzzle blast. I know there are no baffles inside (otherwise you end up in the Federal pound-me-in-the-etc. prison), but it seems that you still have an expansion chamber and then restrict the gas flow out of a bore-sized orifice, which would make a noticeable difference, baffles or not. Uneducated comments are welcome as well -- I'm an uneducated questioner.

The KFH WORKS.  Try it.

Quoted: Quoted: NRA highpower shooters have been using bloop tubes for years(albeit to lengthen the sight radius).  they got that name for a reason.....ie..... big expansion chamber that also probably redirects the sound.   And they are about half a cunt hair from being declared suppressors.

 
That's not very far, and it sucks.

Useful answers, though some are depressing. Couldn't believe M4's XM177 story, but looked up pertinent data and verified yes, if something makes a fookin' loud rifle into a normally loud rifle, it's a suppressor.

Lots of traffic on AR15 portion of the board confirms modog's enthusiasm for KFH.

Thanks.

if bloop tubes are on the way out i wonder what they will say about the ones that are counter bored.  IIRC les baer does this on his (ultra match?).  it is a 30" barrel close to 1" dia counter bored back to 24" of chamber/rifling.  i remember reading that some .22 lr silhouette guys do this also.  16" bull barrel counter bored back to 14.5"(14.5 is supposedly the optimum barrel length for a semi 22lr).