Muzzle brake

[alinwa]

OK, one more thought experiment, and then I promise not to write any more in my apparently vain attempt to keep Newton (Isaac, not Charles) from spinning in his grave (perhaps on frictionless bearings, in a vacuum).

Imagine a rifle with a barrel bent in a U-shape, with the muzzle facing back in the same direction as the shooter. In free recoil, which way will the rifle move after the bullet leaves the muzzle? Will the magnitude of the recoil be the same as, or different from, an otherwise identical rifle with a straight barrel? (Obviously the sign of the recoil momentum vector will be opposite.)

Now in our U-shaped barrel we will put a valve just before the U starts to turn. This magical valve will let the bullet out of the barrel, flying straight downrange, in the same direction and with the same velocity as a bullet from a normal barrel would. However, the magical valve prevents any propellant gas from escaping, and all of those gases (and their momentum) make the U-turn and point back at the shooter (parallel to the axis of the bullet's flight).

Is it possible for the bullet's momentum to be completely cancelled by the gas momentum, yielding a funny-looking, and very loud (for the shooter) recoilless rifle?

Is it possible for the magically-valved, U-shaped rifle to recoil (dare I say it -- rocket) AWAY from the shooter, producing "negative recoil," even though the bullet is speeding downrange?

A muzzle brake is the valve and the U-shaped barrel rolled into one fairly inefficient, but very useful, device. Just like a gimballed rocket nozzle a muzzle brake redirects the momentum of hot gas, producing thrust in the desired direction.

Sir Isaac, R.I.P.

Toby Bradshaw
baywingdb@comcast.net

HelLOOOO????

Toby, this is just silly......

You make statements like " (Obviously the sign of the recoil momentum vector will be opposite.)"


I mean, HOW does one argue with that??!!

Let's just START with this..... "obviously the sign of the recoil momentum vector WILL NOT be opposite."

The gases will still most certainly impinge upon the curved bore, slingshot A'gain.

The vector of force may well be FORCED into reverse/parallel by the fixed steel bore but the momentum vector most certainly will NOT "be reversed"......


dZEEPers!!!


al


If we can get past this then maybe we can find out how much recoil will be reduced by actually somehow EXHAUSTING the gases to the rear. NOT by sending them forward, turning them in a freakin' RACE for cryin' out loud! and then claiming victory........

 

[tim in tx]

toby and alinwa

toby that would be a unique gun[lol]. al would you say that there could be additional forces along with muzzle blast are stopping the rifle such a high press compressed wave just in front of the bullet or sound wave propagation? and the shape of the inside of the brake could change these waves to the benifit of the receivee? tim in tx

 

[alinwa]

Tim,


The compression wave does give a very small reduction, "sound propagation" is simply air compression. We hear through air compression.

Absolutely the inside shape changes the effectiveness.

Here's a site which shows some military brakes, (and pretty much gets the concept right) Note the huge and ugly impingement surfaces in these brakes! Also notice that no attempt has been made to "angle the ports backwards like a rocket." Just great slabs of metal for the gas to slam against.


http://riv.co.nz/rnza/hist/ord/muzzle.htm

al

 

[alinwa]

BTW, as was noted earlier, suppressors or "silencers" are highly efficient muzzle brakes which vent entirely forward! AWEsome use of material.

al

 

[Donnie Nash]

Call Harrels in Salem Va. get one very cheap they work and one more thing that I want to tell you is (THERE IS NO SUCH THING AS A QUIET BRAKE IF IT'S QUIET IT WON'T WORK)!!!!!!!!!

 

[alinwa]

It's so funny searching this stuff.

I've been to 6 mfgr's websites and numerous wiki's.....

Here's a site which again gets it partially right, where they get goofed up is in trying to say that "different types of brakes work differently" which leads me to believe that they're getting their "science" from some of the mfg sites! Most of the guys who make muzzle brakes DO NOT know how or why they work, they "just do."

On this page go clear to the bottom and then scroll back up to the next-to-last paragraph. Find this statement....... "A single large baffle is optimum; leave a hole just large enough for the bullet to pass through and try to have all the expanding gas strike the baffle. This is hard to do as you need several square inches of baffle, since the gas has no mass and only pressure, it needs to be used as soon as possible" ............


http://www.bp-tec.com/recoil.htm

Well, CLOSE but no seegar!

"since gas has no mass and only pressure"......... gotta' love THAT!

LOL


al

 

[AVanGorder]

Brakes without Bullets

A year or so ago, before going on a prairie dog trip, I needed to fire form a bunch of 20 Tactical brass. Basically neck down a 223 then blow it out by pulling the trigger. I didn't want to waste 20 caliber bullets so I just filled up the case with powder, plugged the hole with that light flaky foam stuff you get at Wal-Mart, loaded it and pulled the trigger. I also have a muzzle brake on the rifle. After fire forming a bunch, I decided to remove the muzzle brake and try it.

Results:
Powder only, with brake installed, almost no felt recoil.
Powder only, without brake, much more recoil and gun movement.

Note: of course a 20 caliber doesn't have much recoil to start with (less than a 223), but there was quite a noticable difference.

 

[Big Al]

And because of this, recoilless rifles or guns don't work either?

http://en.wikipedia.org/wiki/Recoilless_rifle

Maybe the reason I'm not getting this from al is because he hasn't told us the reason why they work? I guess this is a secret nobody knows but him, and perhaps one or two others in this world.

al don't keep me in the dark any longer, post a link for me, that gives out the information you have kept secret, PLEASE.

 

[alinwa]

And because of this, recoilless rifles or guns don't work either?

http://en.wikipedia.org/wiki/Recoilless_rifle

Maybe the reason I'm not getting this from al is because he hasn't told us the reason why they work? I guess this is a secret nobody knows but him, and perhaps one or two others in this world.

al don't keep me in the dark any longer, post a link for me, that gives out the information you have kept secret, PLEASE.

secret?

The reason why they work is because the ejecta (gas and particulates) behind the bullet has MASS and VELOCITY, and it's already moving away from you. (handy ) Now, you stick up a series of WALLS and this WIND blows on the walls or baffles and pushes the rifle away from you. It's no more mysterious than hosing off your sidewalk or using a leaf blower.

How they DON'T work is by turning the "nozzle rocket" around and facing it backwards or sideways. The nozzles or baffles or plates just CATCH the gas, the redirection is incidental to the thing.

The link in the post above ( http://riv.co.nz/rnza/hist/ord/muzzle.htm ) is quite accurate in the main.

And YES, if there's no bullet, the baffles will still catch a lot of gas, greatly reducing the negligible recoil produced by just the powder charge. The bullet doesn't have to block the center passage.

al

 

[J. Pendergraft]

secret?

The reason why they work is because the ejecta (gas and particulates) behind the bullet has MASS and VELOCITY, and it's already moving away from you. (handy ) Now, you stick up a series of WALLS and this WIND blows on the walls or baffles and pushes the rifle away from you. It's no more mysterious than hosing off your sidewalk or using a leaf blower.

How they DON'T work is by turning the "nozzle rocket" around and facing it backwards or sideways. The nozzles or baffles or plates just CATCH the gas, the redirection is incidental to the thing.

The link in the post above ( http://riv.co.nz/rnza/hist/ord/muzzle.htm ) is quite accurate in the main.

And YES, if there's no bullet, the baffles will still catch a lot of gas, greatly reducing the negligible recoil produced by just the powder charge. The bullet doesn't have to block the center passage.

al

Al,
It may be more to it than you state. We know for a fact that clam shell type brakes are some of the very best in terms of recoil reduction. If the direction of the gases exiting does not matter then how would you explain the effectiveness of the clam shell type brake?

 

[J. Pendergraft]

Ports and Compensators

Shotgun Porting is conventionally done by drilling small holes on the upper portion of the barrel about 3" rear of the muzzle. Pressures are very low in shotgun compared to rifles but porting is effective in reducing recoil and reducing muzzle rise.

Open Class IPSC guns use compensators, ports or a combination of both. Again these ports are most often facing upward. Some systems are so effective there is no perceivable muzzle rise when the gun is fired. The compensators have walls for the gases to hit but the ports are mostly about bleeding gases upward and to the sides.

IMO the gas jetting effect or what ever is the correct terminology must be significant in terms of recoil and reduction thereof.

 

[alinwa]

Al,
It may be more to it than you state. We know for a fact that clam shell type brakes are some of the very best in terms of recoil reduction. If the direction of the gases exiting does not matter then how would you explain the effectiveness of the clam shell type brake?

The reason that the clamshells are so effective is contained in both of the links above. It's because they have massive "walls" for the wind to blow against. (impinge upon) The walls are angled such as to be perpendicular to the expanding gas mass which is leaving the barrel. They're not "angled back," that's just where they have to be because the gas vectors outward as it exits. The really effective baffles are cupped......some of them are cupped to form a race (like Toby's bent barrel) which the gas slides around, and some are cupped to be more perpendicular. The best balance falls somewhere in between. If the plates are too square to the gas front (angled too far back) then you get all sorts of bounce back to center.

It's just like holding up a 2X4 in the wind VS holding up a sheet of plywood.

And then angle the plywood around for various vectors.

In other words it's not about "exit angle" of the gas leaving the brake......the gas leaving the brake HAS ALREADY DONE IT'S WORK! It's just headed outward or backward because it got bounced there.


All this pressure bleeding off and rocket effect and such are players in this game but NOT to STOP the recoil from hurting you. To STOP or slow down that heavy gun takes a very sharp and immediate impulse. Picture it this way.......if you were laying on the floor and someone dropped the rifle on you, you would NOT want some sort of "rocket" to kick in after the thing touches you.........A "rocket" just ain't gonna' snatch it fast enough. You need to SLAP it forward, overcome it's inertia very quickly. Only the "wind" blowing on the "walls" (baffles) can act this quickly.

Watch a rocket lift off.

Watch a rocket fly and turn....watch a missile turn on a movie.

There ain't nuttin' QUICK about rockets.

I doubt that there's anything on the web about true self-contained recoilless rifles. They do exist, they're just heavy and prone to failure. If there are any airgun guys reading they can comment on "dual opposed piston" systems which utilize this concept for recoilless springers.

al

 

[alinwa]

And because of this, recoilless rifles or guns don't work either?

http://en.wikipedia.org/wiki/Recoilless_rifle

Maybe the reason I'm not getting this from al is because he hasn't told us the reason why they work? I guess this is a secret nobody knows but him, and perhaps one or two others in this world.

al don't keep me in the dark any longer, post a link for me, that gives out the information you have kept secret, PLEASE.

BTW Big Al,

This sort of system was what I'm referring to up in post 41 above you. These "recoilless rifles" do work by exhausting a lot of the ejecta rearward. They're horribly inefficient, hard to clean and deadly on both ends......and far from recoilless for real.

But there are some truly self-contained "recoilless systems" out there too. Systems tailored to small arms like the 45ACP and even 7.62 NATO.

 

[Big Al]

Back in the last century, I was assigned to the U.S. Army Weapons Command in Hawaii with the 25th Division. We did a lot of work on the M-40 106mm recoilless Jeep mounted rifles. These rifles on the tripod exhibited little if any recoil. None on the Jeep mount. It sure was a crew killer, not from firing the weapon but from Jeep rollovers due to the high center of gravity and crushing the heads of the crew.

Never the less, these rifles exhibit no recoil. You may remember that unlike the 105mm artillery piece they have no spring tube recoil assistance.

 

[alinwa]

Back in the last century, I was assigned to the U.S. Army Weapons Command in Hawaii with the 25th Division. We did a lot of work on the M-40 106mm recoilless Jeep mounted rifles. These rifles on the tripod exhibited little if any recoil. None on the Jeep mount. It sure was a crew killer, not from firing the weapon but from Jeep rollovers due to the high center of gravity and crushing the heads of the crew.

Never the less, these rifles exhibit no recoil. You may remember that unlike the 105mm artillery piece they have no spring tube recoil assistance.

In the case of these, the recoil is "balanced" by matching discharge in each direction. I've heard that on the handheld or shoulder-fired units the recoil is variable depending on how clean they are, which rounds were fired, etc. In a perfect world they're relatively recoilless.

al

 

[mks]

secret?

The reason why they work is because the ejecta (gas and particulates) behind the bullet has MASS and VELOCITY, and it's already moving away from you. (handy ) Now, you stick up a series of WALLS and this WIND blows on the walls or baffles and pushes the rifle away from you. It's no more mysterious than hosing off your sidewalk or using a leaf blower.

How they DON'T work is by turning the "nozzle rocket" around and facing it backwards or sideways. The nozzles or baffles or plates just CATCH the gas, the redirection is incidental to the thing.

al

Whether you focus on the pressure on the walls or the redirection of the jet, you get the same resultant force decreasing recoil. The more the jet is turned (up to 180 degrees), the greater the change in momentum of the jet, and the greater the increase in pressure on baffle. It's all the same Newtonian physics. FWIW, in terms of solving the fluid mechanics problem, the pressure approach is difficult because the pressure distribution on the walls is nonuniform and hard to measure. Using integral conservation of momentum with the estimated velocity and direction of the jet is easier.

Cheers,
Keith

 

[alinwa]

Whether you focus on the pressure on the walls or the redirection of the jet, you get the same resultant force decreasing recoil. The more the jet is turned (up to 180 degrees), the greater the change in momentum of the jet, and the greater the increase in pressure on baffle. It's all the same Newtonian physics. FWIW, in terms of solving the fluid mechanics problem, the pressure approach is difficult because the pressure distribution on the walls is nonuniform and hard to measure. Using integral conservation of momentum with the estimated velocity and direction of the jet is easier.

Cheers,
Keith

True, but this is begging the REAL question here. The argument is....."Is the momentum of the gas being redirected doing the work? or is the "jet" doing the work?"


In other words (bear with me ) there are some who feel that if you could magically turn the "jet" around without it battering into the baffles/walls/race that it (the "jet") would act as a muzzle brake. OR, that turning the jet further backwards is more effective.

MY contention is that if you first turned the jet 180degrees backwards and then bounced it back to completely forward again, the muzzle brake would work just fine..... a 360degree muzzle brake. I'm contending that using the "jet's" energy is the func of the brake, NOT redirection of the "jet." In fact just trapping it entire, killing it and making NO jet is best of all Fuh'GIDDABOUT the "jet", just take back the energy.......

It's been done....

It's BEING done daily....

It's called a suppressor.



http://www.ar15-ar15.com/AWC_Systems_Technology_s/52.htm ..... "offers extreme recoil reduction - more effective than any muzzle brake design ..."

http://chrisabraham.com/2006/12/29/all-about-gun-silencers-and-suppressors/ ..... "Suppressors make very effective muzzle brakes. A suppressor reduces the recoil of any firearm by about 30% or as much as a muzzle brake. Unlike a conventional muzzle brake, the suppressor will not blow noise back towards the shooter ..."


al

 

[mks]

True, but this is begging the REAL question here. The argument is....."Is the momentum of the gas being redirected doing the work? or is the "jet" doing the work?"


In other words (bear with me ) there are some who feel that if you could magically turn the "jet" around without it battering into the baffles/walls/race that it (the "jet") would act as a muzzle brake. OR, that turning the jet further backwards is more effective.

MY contention is that if you first turned the jet 180degrees backwards and then bounced it back to completely forward again, the muzzle brake would work just fine..... a 360degree muzzle brake. I'm contending that using the "jet's" energy is the func of the brake, NOT redirection of the "jet." In fact just trapping it entire, killing it and making NO jet is best of all Fuh'GIDDABOUT the "jet", just take back the energy.......

It's been done....

It's BEING done daily....

It's called a suppressor.




al

Newton says that force equals change in momentum. Suppressors work because dissipating the momentum involves eliminating the forward momentum of the jet - the same change in forward momentum as turning it 90 degrees. But turning it 180 degrees creates twice the change in momentum, therefore, twice the force. Conversely, any change in momentum requires that a force be applied, from the baffles or some other way. The force and the change in momentum are two side of the same coin, so to speak.

Cheers,
Keith

 

[haze10]

IF you can find it, get the book, ""Gun Muzzle Blast and Flash" by Klingenberg and Heimerl. They have a chapter on baffle brake design. You can also get literature from the government, declassified brake testing for both baffle and perforated.

Brakes are measured in efficiency. A well designed baffle brake can generally be twice as efficient as a perforated brake. There is preferred locations of the baffles in relation to distance from the muzzle.

The brakes work off gas momentum. Overbored cartridges have a lot of excess gas. The 416 Rigby is NOT going to have a lot of gas momentum. So if you want any significant reduction, you will need the most efficient brake you can find. Big wall plates are what you look for. The two that come to mind is JP two baffle, or the Barrett large multi baffle. Both of which will look out of place on your bolt action. If you have to have something, then a gill brake may be a good compromise.

 

[alinwa]

IF you can find it, get the book, ""Gun Muzzle Blast and Flash" by Klingenberg and Heimerl. They have a chapter on baffle brake design. You can also get literature from the government, declassified brake testing for both baffle and perforated.

Brakes are measured in efficiency. A well designed baffle brake can generally be twice as efficient as a perforated brake. There is preferred locations of the baffles in relation to distance from the muzzle.

The brakes work off gas momentum. Overbored cartridges have a lot of excess gas. The 416 Rigby is NOT going to have a lot of gas momentum. So if you want any significant reduction, you will need the most efficient brake you can find. Big wall plates are what you look for. The two that come to mind is JP two baffle, or the Barrett large multi baffle. Both of which will look out of place on your bolt action. If you have to have something, then a gill brake may be a good compromise.

Well said Haze,

And as to your ref of "the 416 Rigby is NOT going to have a lot of gas momentum" let me add that generally speaking the more INEFFICIENT or overbore the round is, then the more EFFECTIVE the brake will be....... because it has more of a "gas train" to catch and work with.

("I just made that up,"-- Waylon Jennings. )

al