Linear compensators

[Bullseyetony]

I ordered one a while back and just installed it this past weekend but haven't had a chance to try it out. Any advantage or disadvantages to these? My logic was that it would be quieter to my ears when hunting/shooting. Anyone run one of these?

[FRB6.5]

The advantage is they are less annoying to the shooter and bystanders Vs a typical side vented brake. The disadvantage is they are not as effective in recoil reduction or muzzle rise.

[danm]

The advantage is they are less annoying to the shooter and bystanders Vs a typical side vented brake. The disadvantage is they are not as effective in recoil reduction or muzzle rise.

This sums it up really good. I use em on all my lower recoiling rifles, 5.56 6.5G and save the obnoxious brake for my 6.5 PRC bolt gun which actually needs some recoil mitigation.

[A5BLASTER]

Had that same model on my 12.5 inch grendel. Honestly it wasn't any quieter to my ear then my 12 inch with a a2 flash hider installed on it.

[Bullseyetony]

They're cheap so if I don't like it I'll just put the flash hider back on which did just fine. Just trying new things I guess.

[SDW]

Interesting subject. Apparently, a slight reduction in sound (compared to the same gun with a bar muzzle) heard by the shooter is measurable using decibel meters. But I am a little puzzled as to why. I often read the "reason" explained as "it directs the blast forward". But I don't believe sound works that way. I mean, what would do that better than a bare muzzle, right? Maybe swap out that linear compensator for four more inches of barrel? It would still be loud AF. Once it leaves the muzzle and enters "our world", the blast goes in all directions. I did read one explanation that made a little more sense. Something about the LC behaving like an expansion chamber. The blast is still in a tube, but the tube got a lot fatter, maybe taking away some of the energy? I don't understand it well enough to explain it well at all I'm afraid.

Here's an interesting article describing blast waves, sound waves, etc.

https://www.americanscientist.org/article/high-speed-imaging-of-shock-waves-explosions-and-gunshots

And from that article is this cool pic of a 30-'06 hunting rifle being fired, using shadowgraph photography. The big ball is the blast wave, with sound waves right behind it. Just ahead of the muzzle is the 'fireball' of flame and smoke, expanding radially as well as forward. And of course that cone is the bullet's own shock wave, but that is a whole other story.

I would like to see a pic like this of a rifle with a LC on the end, just to see if it looks any different somehow.

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[drewthebrave]

Interesting subject. Apparently, a slight reduction in sound (compared to the same gun with a bar muzzle) heard by the shooter is measurable using decibel meters. But I am a little puzzled as to why. I often read the "reason" explained as "it directs the blast forward". But I don't believe sound works that way. I mean, what would do that better than a bare muzzle, right? Maybe swap out that linear compensator for four more inches of barrel? It would still be loud AF. Once it leaves the muzzle and enters "our world", the blast goes in all directions. I did read one explanation that made a little more sense. Something about the LC behaving like an expansion chamber. The blast is still in a tube, but the tube got a lot fatter, maybe taking away some of the energy? I don't understand it well enough to explain it well at all I'm afraid.

This is what I wonder as well. I would love to see a comparison of the barrels & devices listed below to measure the volume and "blast" experienced with each of the following:
- 12" barrel with a range of linear compensators
- 12" barrel with bare muzzle
- 14-16" barrel (roughly equivalent to the length of the 12" barrel + linear comps) with a bare muzzle

I suspect that most linear compensators do little to actually mitigate the soundwaves versus a bare muzzle, but I don't know enough about the physics of gas expansion to do anything but speculate. I have a handful of thread protectors and muzzle devices that I've tried over the years, but I haven't really felt the need to go for a linear compensator over a bare muzzle yet.

If the benefit could be measured & quantified, I might consider it. But as far as I can see, it seems like linear comps are a mostly cosmetic choice to make an AR pistol look like a Honey Badger, which I'll admit looks pretty dang cool. But if a longer barrel is about as loud (from the shooter's perspective) as the shorter barrel + linear comp, I'd rather have the additional velocity from the extra barrel length.

[SDW]

I suspect that most linear compensators do little to actually mitigate the soundwaves versus a bare muzzle, but I don't know enough about the physics of gas expansion to do anything but speculate. I have a handful of thread protectors and muzzle devices that I've tried over the years, but I haven't really felt the need to go for a linear compensator over a bare muzzle yet.

If the benefit could be measured & quantified, I might consider it. But as far as I can see, it seems like linear comps are a mostly cosmetic choice to make an AR pistol look like a Honey Badger, which I'll admit looks pretty dang cool. But if a longer barrel is about as loud (from the shooter's perspective) as the shorter barrel + linear comp, I'd rather have the additional velocity from the extra barrel length.

I think part of the spread of the lore is because people have swapped to the LC from a standard muzzle brake. Of course the LC seems quieter. Nobody (that I know of) starts with just a thread protector and then puts on a linear comp to try to quiet it down. I think many people would not want to swap from a brake to a plain barrel end. They just wouldn't. Gotta have something cool looking on the end.

However, here's an honest test of sound level for various rifles, with and without a linear comp. Saw this the other day after reading a LC thread on Calguns.net. Got me curious and I found this. The muzzles are as I said, slightly quieter... behind the rifle. I would like to see for fun, simultaneous measurements 5' behind the rifle and 5' in front, just to see if there's anything to this "blast directing forward" deal. It is possible for sound to reflect off surfaces of course. That's why brakes are so damned loud when standing behind or the sides. Might be interesting to measure the sound ahead of the muzzle to see if a LC produces a louder noise out front than the bare muzzle. That's be evidence of the sound reflecting forward. Then if not any louder out front, it would have to be due to some other phenomenon.

[FRB6.5]

An interesting post on arfcom related to this discussion:

https://www.ar15.com/forums/General/Did-you-guys-know-this-/5-2347477/

[SDW]

An interesting post on arfcom related to this discussion:
https://www.ar15.com/forums/General/...is-/5-2347477/

That is interesting. Thanks. One thing about the quote in there. The guy was only talking about containing sound waves. Didn't say anything about the initial shock wave (assuming the blast is super-sonic), which is moving a bit faster than the emanating sounds. But I guess it's all part of the same problem. No way to direct any of that with any kind of precision.

I was participating in another forum's thread about this topic. I tried to show them a little science, like the above article, about how a blast/explosion first creates shock wave, and behind that comes the various sound waves. And how sound from a gun moves pretty much in all directions. And since it reflects of solid things, if the barrel has something like a standard brake on the end, some of that shock and sound reflects back, increasing what's heard behind and to the sides of the muzzle. I don't think those guys were too interested in the physics of it though. I guess it disagreed with what they'd heard about linear comps on Youtube gun channels.

So anyway, I was saying there that I think some people must believe that a linear comp works like a megaphone, projecting the sound forward. But I don't think that a short, small diameter tube with straight walls behaves like a megaphone. The device would need to be conical in shape, or horn shaped, in order to reflect sound forward. There are some audio people on that board as well. I am hoping they might weigh in with their thoughts.

[FRB6.5]

Some of them are cone shaped internally, Black River Tactical and KAK flashcans (no compensation/brake effect to speak of on the KAK).

[SDW]

Thanks. I had no idea about that. Never seen a cutaway. Makes me think of the old-school "flash hiders" of the two World Wars. I wonder, did these devices make the machine-guns any quieter for the operator?


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