Muzzle brake

ding,ding,ding,ding! We have a winner!

Yes, and this is also why , in a brake like pitured above, the first two rows of holes(nearest the gun) do about 80% of the work. Without a brake you do have a substantial rocket affect. With a brake some of the gasses will pull the gun forward and a large percentage of what is left over is negated by the opposing holes..thereby negating the rocket effect (to a large degree)as well. The gasses will follow the path of least resistance and the bulk of those gasses are gone in a VERY small amount of time...hence the first holes doing most of the work. But witout a brake, they are all released in the same direction. At roughly 6000psi, that short burst is felt.---Thanks, Mike Ezell
 
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Smith Enterprises

brian roberts said:
but you might just speak w/Ron Smith, over at Smith Enterprise, he makes brakes for M-1s, M1As, & ARs. They are really effective, the Garand & M1As feel mutch like .243s. I'm not saying its THE thing to have, but he's wanting to get more word out on that aspect, I'm told. He is VERY busy, a great deal of contract work for the services, right now. Talk to him, you might work out something on the experimental side that will be mutually beneficial. He does make a high quality product, & I can attest, it works well on the platforms I've used them on, I've installed three, & on my recommendation, another 'smith installed three, & he was(figuratively) blown away w/the results.:rolleyes:
Click to expand...

I'll second the vote for Smith Enterprises brakes for semi auto taming. Had one on my HK-91 and have one on my HK-93.

Lou Baccino
 
Nice try Toby ;) and nice recoil calculator.

OK, first of all, the rocket effect EXISTS, it even pushes back a little, it just ain't what makes a muzzle brake work.

Another thought experiment........ exactly HOW MUCH of the total recoil impulse is the result of the small burst of accelerating gas which exits behind the bullet.

I'll suggest that it's possibly as much as 1/10th of 1% or 1/1000th of the total recoil impulse. IF that 1/1000th is what we have to work with, exactly how much work can you get from it?

al
 
Everyone has been right to varying degrees about why a gun recoils less with a brake. A brake is just a very inefficient thrust reverser...Ineffiecient because most of the pressure that is "caught" is simply vented somewhat perpindicular to the barrel, and a VERY small percentage of the gasses DO "grab" and pull forward on the brake...but that small percentage is effective, and greater surface area will increase it's effectiveness. If you could capture all of the gas at the muzzle and use it all to pull forward on the gun it would come forward with substantial force. A brake does two basic things.
1.)It captures a small percentage of gas and uses it to pull forward on the gun.
2.)It negates a large percentage of the "rocket effect" that you would have without the brake by venting the gasses off in opposing directions somewhat perpindicular to the barrel.

If anyone is still unsure that the "jetting" or "rocket effect" is real, make a brake with holes only on the bottom and report back to us. Just do so at your own risk.

alinwa, What you are saying suggests that the gasses are more "powerful" at pulling than they are at pushing.
--Mike Ezell:)
 
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mwezell said:
If anyone is still unsure that the "jetting" or "rocket effect" is real, make a brake with holes only on the bottom and report back to us. Just do so at your own risk.

alinwa, What you are saying suggests that the gasses are more "powerful" at pulling than they are at pushing.


--Mike Ezell:)
Click to expand...

Ohhhh I can and do do more than that :) I routinely fireform using 70gr of powder only. That's 70gr of ejecta and a flame 6' long..... it kicks like a 22LR.

What I'm saying is YES that the gases leaving, while not "more powerful at pulling," (WTH does THAT mean!!) are certainly set up to do a LOT more work. They are charging full-tilt on like a T'undering Herd of Heffalumps, they've got a tremendous inertial load to dump somewhere. That little spurt behind the bullet on the other hand ...... ????? .........I build rockets from scratch, solid and liquid fuel. Believe me, that liddle wad of pent gas which escapes after the bullet leaves does NOT add materially to recoil impulse.

Using the inertia of something already in motion isn't "more powerful" than trying to use something else entirely, it's just good use of what's available. I'm really not sure WHAT you're implying here. On the one hand you've got a huge impulse to work with/scavenge from and on the other we've got a mouse fart. I guess then that from your perspective YES I'm saying that IMO the moving gas column is MUCH, like HUGELY, more "powerful" than the mouse fart that's contained by the barrel/chamber reservoir. That tablespoon of 6000 psi gas ain't gonna' do much more than blow a paper cup off the counter from 5ft away.



BTW, the gases aren't "pulling".........there is no such force. (Except MAYBE in trees.) The moving gases are impinging (PUSHING) the baffles in the brake exactly like the wind pushes a boat or a sheet of plywood or a kid on a stateboard. OR, exactly like a semi tractor PUSHES it's trailer down the road. Just because it's trailing doesn't mean that it's "pulling."

:)


al
 
OHhhhhh, OOOPS!


I missed this one.


And BTW, the muzzle brake is certainly NOT "an efficient thrust reverser".......... Ain't even a POOR thrust reverser, it just ain't ABOUT "thrust"....

al
 
alinwa said:
Another thought experiment........ exactly HOW MUCH of the total recoil impulse is the result of the small burst of accelerating gas which exits behind the bullet.

I'll suggest that it's possibly as much as 1/10th of 1% or 1/1000th of the total recoil impulse. IF that 1/1000th is what we have to work with, exactly how much work can you get from it?

al
Click to expand...

You can use the recoil calculator to do the figgerin'. Just make "Load One" the real thing, and for "Load Two" put the total powder+bullet weight from Load One into the bullet weight cell of Load Two. Put a zero in the cell for powder weight in Load Two. Make the muzzle velocity and rifle weight the same for both loads.

Now we have two loads with the same mass, but only Load One has a rocket effect.

For a typical 6BR load of 107gr bullet over 30gr of powder (3000fps, 10lb rifle) the rocket effect produces about 7% of the total recoil impulse and about 13% of the total recoil energy, if you believe the recoil calculator. (I have no idea how the calculator is estimating the velocity of the escaping gas.)

All of the momentum from the propellant gases is potentially available for reducing recoil -- not just the extra momentum from the rocket. In the load above the powder gases produce about 47% of the total recoil energy, so 28% of all the recoil energy that comes from the powder gases is produced by the rocket effect. Not surprising, really (to me, anyway), given the high velocity of the gas once the bullet moves out of the way.

Toby Bradshaw
baywingdb@comcast.net
 
mwezell said:
Whatever you say, alinwa....You build model rockets.:D:D:D-Mike Ezell
Click to expand...


Well, have you ever built one? Do you realize how much thrust it takes to move even a small rocket? A typical toy Estes rocket motor contains 5 times the fuel of say a 6BR.


tobybradshaw,

No, in this case I don't believe the calculator. Not because it's WRONG but because it's being misapplied.



BTW, since both you'se guys is laffing at my "rocket" analogies......try it your way :) Build a rocket with outward-facing ports and see how she lifts! Schucks, face 'em "rearward" a little......give yourself a break!


LOL


al
 
alinwa said:
No, in this case I don't believe the calculator. Not because it's WRONG but because it's being misapplied.

al
Click to expand...

Not misapplied, just tricked into doing my bidding. :)

But if you Google other loading programs, like "Load from a Disk," they estimate the escaping gas velocity as 1.5x the muzzle velocity, so around 4000-4500fps for most rifle loads. Accelerating 30gr of propellant gas from the muzzle velocity (3000fps) to the maximum velocity (4000-4500fps) will increase the momentum of the gases by 30-50%, which is in the same ballpark as what the recoil calculator gives for the rocket effect as a proportion of total propellant-induced recoil (no doubt because all these programs have a similar estimator for gas velocity).

Check it out: http://www.loadammo.com/Topics/August01.htm

Not too hard for me to believe that the gases are going quite a bit faster than the bullet, as anyone who has put a chronograph too close to the muzzle can attest.

Toby Bradshaw
baywingdb@comcast.net
 
BTW, since both you'se guys is laffing at my "rocket" analogies......


alinwa,
I'm not laughing at you or your analogy
 
Ok, Toby we're being side tracked a little I think by all the rocket stuff. ;) The "rocket effect" DOES EXIST....... it just doesn't apply.

Let me try another way. Let's say that the rocket effect does account for 10% of the total recoil.

Let's say that we convert 1/2 of this directly to the rear, or use 1/2 of it to counter the total recoil.

So now we've turned 5% of the recoil "backwards" ..... or "cancelled" 10% of it?

Or reduced recoil by 10% ?????

I can assure you that shooting a 50BMG even with recoil that's reduced by 10% will HURT!

The rocket effect, while an interesting sidebar issue, is NOT what makes a muzzle brake work.


PLUS....... rockets are steenking SLOW! Trying to catch a 50BMG with rocket propulsion might catch you about the time you bounced off the rear wall of the shooting shed. A muzzle brake YANKS that gun forward like a string attached to the bullet.


A correction,


I misspoke earlier when I said that I "routinely fireform using 70gr of powder only. That's 70gr of ejecta and a flame 6' long..... it kicks like a 22LR." This is untrue. I use 70 CLICKS on a Harrell which is only 35gr or so of propellant. I've never actually weighed this charge.



al
 
As I said before, all of the recoil produced by the propellant (including, but not limited to, the rocket effect) is potentially available to reduce recoil via a muzzle brake (which itself can be thought of as a rocket nozzle -- albeit an inefficient one).

The muzzle brake just points the momentum vector of the propellant gases in some direction other than downrange, and any direction other than straight downrange reduces recoil. If the muzzle brake could turn all the propellant gases around and point them directly back towards the shooter (without any loss of energy), not only would all the propellant-induced recoil be eliminated, but some (or even all, if the propellant contributes more than half the total recoil) of the bullet's recoil could be eliminated, too. Noisy little SOB, though! :)

Nobody has claimed that the rocket effect is the ONLY thing that matters for muzzle brakes, just that it matters about 100 times more than your estimate of 0.1%.

Toby Bradshaw
baywingdb@comcast.net
 
I think if I was on the side of the argument that has rejected NEWTON'S second and third laws as having any effect on muzzle brakes, I would perhaps want to read a little further on the subject.

I tried this just to make this easy. I typed in Google, How do muzzle brakes work. I hit Chuck Hawks and this is what I found.

http://www.chuckhawks.com/muzzle_brakes.htm


And to this I have observed in the past, Braking a vacuum many times.

"BTW, the gases aren't "pulling".........there is no such force. (Except MAYBE in trees.) The moving gases are impinging (PUSHING) the baffles in the brake exactly like the wind pushes a boat or a sheet of plywood or a kid on a stateboard. OR, exactly like a semi tractor PUSHES it's trailer down the road. Just because it's trailing doesn't mean that it's "pulling."

Nature abhors a vacuum and yes there is such a thing or force happening in this world. Low pressure and high pressure causes a thing we call the wind.

We could go on for ever about the siphon effect in nature and point to more "Natural Laws". But I won't point to any more such evidence.
 
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about brakes

i think the holes on the sides are not doing the majority of the braking ,the wall or large flat surface at the end of the chamber or the front of the holes[no chamber] this wall is doing at least 70% of the peak stopping force ,i did an experiment ,i eliminated that wall that is ussually there with a typical brake. a design which consisted of a chamber 3/4 id , roughly an inch deep , with a reverse cone at the end of the chamber ,my thoughts were to scrape as much of the gas off of the bullet, it caught me off guard on the first shot[240s, w/308 baer case in a light gun,and yes did hold it a little loose ,man it puched me good.i was stunned the brake was not working at all it seemed,after a few more shots i couldnt handle it so went back to the shop and threw the brake back in the lathe and cut the reverse or inverted cone out of the end of the chamber , so much for that . i went back to standard angles but leaning forward .the brake worked absolutley awsome i could shoot it pretty much free recoil.as well i think by channeling the air inward through the exit hole is a benefit to accuracy, it has been said that it can stabalize a slightly yawing bullet [caused by in bore yaw] by going through a jet stream vortec of sort that is at the exit hole. and seems by that effect i have seen accuracy gains as well by going to a standard forward cone shape, [in this case 11 degrees]. hope this helps. tim in tx
 
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Toby,

"(which itself can be thought of as a rocket nozzle -- albeit an inefficient one)."



THIS :) above, is where we part ways....... :)

It is in no way related to a rocket nozzle. RECOIL is due to Newton's Laws, the small added "rocket effect" is negligible but more importantly the muzzle brake works because high speed gas is hitting it like wind against the side of the barn. Or dragging a corn cob through a ......... anyway, it's the inertia of the escaping gas PUSHING on the surfaces of the muzzle brake that reduce recoil. It ain't a "rocket nozzle"..... it's a steenking WALL!


Paragraph two is equally flawed....... no you could NOT turn the flow back around ("reverse the thrust") and eliminate the recoil of he bullet. You could nearly counter the recoil (COUNTER, not eliminate) generated by the GAS because the impact of it hitting the wall to "turn around" and come back at you would knock the rifle forward, but AGAIN....... NO ROCKET here, all you're doing is slingshotting the mass of the gas.


al


Ohhhh, and AGAIN The inimitable Chuck Hawk is proven to be clueless :) I've been over there at least ten times in reference to something or other and each time he has it wrong....... In the first paragraph he makes this statement " Muzzle brakes reduce recoil by diverting part of these gasses to the side so that they do not add to the rearward recoil."

NOT!




Now, the REST of the article is actually perty good, if only if only the dude wouldn't try to UNDERSTAND stuff he'd be OK. You oughtta' see his stuff on exterior ballistics, wind drift and shooting uphill/downhill!
 
i think alinwas point is

brakes dont not reduce the energy of the recoil,they reduce the length of travel of the gun from the energy produced.hold it loose with a brake and you will never feel it punch,but hold it tight and you will feel the punch ,it just doesnt blow you back a foot .just blows you back an inch but with just as much energy. the reason being the bulk of the energy is produced from the bullet getting started in the barrel. tim in tx
 
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
 
tim in tx said:
brakes dont not reduce the energy of the recoil,they reduce the length of travel of the gun from the energy produced.hold it loose with a brake and you will never feel it punch,but hold it tight and you will feel the punch ,it just doesnt blow you back a foot .just blows you back an inch but with just as much energy. the reason being the bulk of the energy is produced from the bullet getting started in the barrel. tim in tx
Click to expand...

Well, no......

The brake actually DOES significantly reduce recoil, just exactly like the brakes on your car. The gun starts back, hard, and the brake "catches" it before it hurts you. The really cool thing is how it uses energy that's ALREADY BEEN PRODUCED, it's as if you tied a string to the bullet, when the bullet hits the end of the string it pulls the rifle forward.

al
 
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