I agree your test setup is ideal for measuring recoil energy. I think a load cell has its own set of challenges and I beieve people have tried load cells with less than optimum results.
Can switching muzzle brakes change muzzle velocity??
- Thread starter Timber338
- Start date
Help Support Long Range Hunting Forum
I agree your test setup is ideal for measuring recoil energy. I think a load cell has its own set of challenges and I beieve people have tried load cells with less than optimum results.
The basic energy formula is;
E=1/2mv^2
That says that all of the E (energy) is equal to one half the of the m (mass) times the v (velocity) squared. A change in the mass or velocity of any part of the system takes a portion of the E. Since the mass (m) doesn't change and the energy (E) doesn't change, then the velocity (v) has to change. The velocity of the rifle moving is where the rest of the E is going. Fix the rifle from moving and the v of the bullet and gas will increase.
E=1/2mv^2
That says that all of the E (energy) is equal to one half the of the m (mass) times the v (velocity) squared. A change in the mass or velocity of any part of the system takes a portion of the E. Since the mass (m) doesn't change and the energy (E) doesn't change, then the velocity (v) has to change. The velocity of the rifle moving is where the rest of the E is going. Fix the rifle from moving and the v of the bullet and gas will increase.
I think the E is changing because each brake directs the gas portion of the E differently. Some push more out to the sides (dropping E in the direction of travel) and other brakes push more gas out with the bullet increasing E. That's a simplification since port angle comes in to play.
Or do you picture it differently?
Nope I believe that's accurate. The part that is the most difficult is the fluid dynamics and the effect the super sonic gas stream has on the bullet' velocity. Being that the gas stream is still pushing static air out of the way, I suspect it does effect the bullets velocity. With a brake you redirect the gas to oppose the reactive force (recoil). That redirected force would be traveling with the bullet. I suspect the gas out accelerates the bullet as it leaves the barrel (and delecerates rapidly due to its low mass). I think the gas column projected around the bullet reduces the bullet's initial deceleration. I have to say I'm speculating on the external fluid dynamics of the system.
If your theory about a brake changing the velocity was sound and you want to argue about the travel affecting the velocity then why does the round with no brake have a velocity exactly the same as the previous round yet it travels 3 times further on the sled? And why doesn't the velocity follow the amount of travel with every shot?
I went through physics in college too and know the formulas. I have to test again in the next few days and can get velocities on and off the sled but I'll bet you there is no significant difference in the two. Calculations and the real world don't always mesh typically because something is being overlooked in the calculations. In this case I think your overlooking the fact that the energy used to accelerate the bullet after it leaves the muzzle isn't the same energy being used to reduce the recoil. The energy used to accelerate the bullet doesn't change with or without a brake because it exits the brake behind the bullet.
I went through physics in college too and know the formulas. I have to test again in the next few days and can get velocities on and off the sled but I'll bet you there is no significant difference in the two. Calculations and the real world don't always mesh typically because something is being overlooked in the calculations. In this case I think your overlooking the fact that the energy used to accelerate the bullet after it leaves the muzzle isn't the same energy being used to reduce the recoil. The energy used to accelerate the bullet doesn't change with or without a brake because it exits the brake behind the bullet.
I hear ya. From the research I've done on recoil energy, you start out assuming that the gas is escaping the barrel at 4000 FPS. Of course that's an estimate but I believe goes along with your thinking that the gas is moving past the bullet when it first exists the barrel.
Definitely some complicated fluid dynamics going on and I don't think I personally understand the reality of what's happening.
I do have a coworker that recently completed his PHd in propulsion engineering and he's been working in this field for nearly 2 decades. He also happens to be my neighbor and we've been discussing all of this recently over beers. We've both been too busy with our kids (both of us have toddlers) and just don't have the bandwidth to do any real work on this. Maybe sometime this winter when it's too cold to do anything else.
Definitely some complicated fluid dynamics going on and I don't think I personally understand the reality of what's happening.
I do have a coworker that recently completed his PHd in propulsion engineering and he's been working in this field for nearly 2 decades. He also happens to be my neighbor and we've been discussing all of this recently over beers. We've both been too busy with our kids (both of us have toddlers) and just don't have the bandwidth to do any real work on this. Maybe sometime this winter when it's too cold to do anything else.
Idaho, your real world tests are very compelling. Keep us posted with the test you run soon.
Cool test setup you've got too. One thing I've always wondered that I bet you have a grasp on is when you see two different brakes perform differently by say 2 inches of sled recoil, is that noticeable? I guess a better way to phrase the question is at what point are two brakes indistinguishable with perceived recoil? Or at what point of sled recoil is one brake going to produce noticeably less recoil? With the smaller cartridges you test it seems all the brakes seem to stack up next to each other like your .308 win test. Then there is a larger difference in sled recoil for each brake on the larger cartridges like the Lapua.
Cool test setup you've got too. One thing I've always wondered that I bet you have a grasp on is when you see two different brakes perform differently by say 2 inches of sled recoil, is that noticeable? I guess a better way to phrase the question is at what point are two brakes indistinguishable with perceived recoil? Or at what point of sled recoil is one brake going to produce noticeably less recoil? With the smaller cartridges you test it seems all the brakes seem to stack up next to each other like your .308 win test. Then there is a larger difference in sled recoil for each brake on the larger cartridges like the Lapua.
The "buffering" the escaping gases have on the bullet is pretty insignificant. The average bullet loses 150-200fps in 100yds. Those gases only out run the bullet for a few inches. Do you really think that "buffering effect" will amount to 47fps in a couple inches? Not likely or you'd hear of people complaining of large velocity losses all the time after they installed muzzle brakes. You never hear that and I've never witnessed it. I'd be willing to bet I've installed more muzzle brakes then all but a small handful of people on this site.
Everyone's perceived recoil is different so it's hard to say what each individual feels but when brakes stack up like that the odds are people can't tell the difference. I do think most people will feel the difference in the brakes that have several inches of separation on the sled especially with the lighter recoiling calibers. I also think how the rifle reacts to recoil changes a persons perceived recoil too. In others words how much the rifle jumps when shot will change how people react to it.
J E Custom
Well-Known Member
"WOW" I finally read through this entire thread and it was deja vu all over again because I heard all of the many theories and had a few of my own so I wanted to prove or disprove them to my self.
Years agoI started testing all Of the theory's of the time because I was unsatisfied with the performance of existing brakes, and read everything about muzzle brakes that I could find. Hatchers Notes was one of the best sources because he had tested for the government at Aberdeen proving grounds for many years.
First, a consistent means of testing had to be developed that was 100% repeatable and as accurate as possible, or the test would not be valid.
There are many post on this process and the method finally decided on and a search can give this information so no need to rehash this process.
Once an Instrument/device was developed that met the requirements, design testing could began.
In order to get as much information as possible, we used slow motion Videos and a DB meter to record sound levels in addition to all recoil data, plus cartridge performance (powder type and amount, velocity, bullet weight, rifle weight as shot (Scoped or not). This gave us lots of information when all of this data was combined that was very important and showed cause and effect of the differences in any change.
Very little was truly understood about how a muzzle brake worked and how to improve the performance in any area (Recoil energy, loudness, perceived recoil, signature, effect on the projectile, Recoil velocity, Effects on other persons near by, shock wave direction and effect, and anything else we could learn.
Theories are a good way of getting started, but we set out to prove that they were true or false.
with real world test I feel we accomplished what we wanted to and truly understand the function and physics of brakes.
I don't claim to be the last word in this or the authority on muzzle brakes, but I do understand them a lot better and can predict what design changes will do with 99% confidence and can back up the claims I have posted.
Note: I do not sell muzzle brakes for a living and my only interest was to improve them If I could. I have built some for friends for field testing and the results have proven to be accurate. So this is not a sales pitch and If someone doesn't believe the test results that is there right and everyone is entitled to there opinion. None of our results are opinions, they are based on real test and have been proved time and again throughout our testing.
So to keep this short enough to read I will answer some of the points/theories brought up in this thread based on our testing.
A muzzle brake properly designed and installed will not effect velocity, It can effect accuracy and Point of impact, because of the difference in weight that can change the barrel harmonics. and if it is cast and/or the opposing ports/holes are precisely the same, it causes an imbalance of forces that can effect accuracy.
When a bullet leaves any firearm, the bullet velocity is at its peak and slows very little in the first few inches, the gas however instantly starts to slow rapidly because it has by nature, very little mass and therefor the bullet frees its self of any effect of the gas just like the bullet crown does.
If you watch any slow motion Video or a weapon being fired you will be amazed at how far the bullet is from the muzzle when the gas appears and also how far the bullet is when the recoil appears and the weapon starts to move.
More than anything port angles create more or less noise for the shooter or the spotter and have very little effect on Recoil. A well designed brake is the total combination of all the best choices with some compromises to reach a good balance for overall performance.
Our test showed that there were "NO" quite brakes. They all ranged from 105 DB to 108 DB with or without a brake. the Perceived noise was greatly changed depending on the type of brake and the position of the person. But the DB meter showed the level of noise to be within these ranges.
Each Load has its own bullet energy recoil and its own powder recoil potential The bullet recoil energy of any bullet can only be changed by changing the velocity or the weight of the firearm.
The Gas recoil is what the brake "Can" deal with and this is where the recoil reduction is found
when using a muzzle brake. But when dealing with any gas recoil the total recoil developed, cannot exceed the potential. (Example: If the total gas recoil produced is 60%, the recoil reduction can't be more than 60 % so somewhere under that number is where it recoil reduction will fall. This does not mean that the rifle recoil will be reduced by 60% because there is still the bullet recoil that has to be added to that.
Another example is the testing we did on the 50 BMG. the rifle produced a total recoil of 110.6 ft/lbs
of recoil without any muzzle brake. with the factory brake muzzle brake the rifle produced 77.1 ft/lbs of recoil for an efficiency of 30.2%. With the first Prototype, the total recoil reduction was 59.3 ft/lbs for a gas reduction of 60.5% of a possible 66.8% of the gas recoil. Once we figured out that tuning the brake for the most efficient gas management of the specific load we were able to get the efficiency to 98% for a total reduction of 41.3 ft/lbs of recoil. So from 110.6 to 41.3 ft/lbs recoil reduction made the 50 BMG pleasant to shoot.
The fact that a muzzle brake works based on the gas recoil limits the total amount of recoil you can expect from a cartridge and can't change anything else needs to be understood to take advantage
of what your Bullet to gas Ratio is to get the optimum performance from a brake.
The bigger/heavier the bullet, the lower the powder recoil and the higher the bullet recoil energy ratio will be reducing the total recoil potential of a brake. (If a bullet to powder ratio is 40;60, the most you recoil % you can get is below 60% of the gas recoil + the bullet recoil (Inertial).
I hope this is clear and explains what a muzzle brake really does and how it works despite all of the theories we have heard. I had plenty of ideas and misconceptions before we started to test and now I know the facts as the test have proven and I am comfortable with all of the results.
Sorry for the long post, but I don't like just making a statement without something to back it up.
Just the facts as I know them based on the extensive testing. If anyone is interested in looking at some of the Video testing, go to
www.jecustom.com - Home of the Assassin Muzzle Brake and look at the 8 Videos we have posted.
J E CUSTOM
Years agoI started testing all Of the theory's of the time because I was unsatisfied with the performance of existing brakes, and read everything about muzzle brakes that I could find. Hatchers Notes was one of the best sources because he had tested for the government at Aberdeen proving grounds for many years.
First, a consistent means of testing had to be developed that was 100% repeatable and as accurate as possible, or the test would not be valid.
There are many post on this process and the method finally decided on and a search can give this information so no need to rehash this process.
Once an Instrument/device was developed that met the requirements, design testing could began.
In order to get as much information as possible, we used slow motion Videos and a DB meter to record sound levels in addition to all recoil data, plus cartridge performance (powder type and amount, velocity, bullet weight, rifle weight as shot (Scoped or not). This gave us lots of information when all of this data was combined that was very important and showed cause and effect of the differences in any change.
Very little was truly understood about how a muzzle brake worked and how to improve the performance in any area (Recoil energy, loudness, perceived recoil, signature, effect on the projectile, Recoil velocity, Effects on other persons near by, shock wave direction and effect, and anything else we could learn.
Theories are a good way of getting started, but we set out to prove that they were true or false.
with real world test I feel we accomplished what we wanted to and truly understand the function and physics of brakes.
I don't claim to be the last word in this or the authority on muzzle brakes, but I do understand them a lot better and can predict what design changes will do with 99% confidence and can back up the claims I have posted.
Note: I do not sell muzzle brakes for a living and my only interest was to improve them If I could. I have built some for friends for field testing and the results have proven to be accurate. So this is not a sales pitch and If someone doesn't believe the test results that is there right and everyone is entitled to there opinion. None of our results are opinions, they are based on real test and have been proved time and again throughout our testing.
So to keep this short enough to read I will answer some of the points/theories brought up in this thread based on our testing.
A muzzle brake properly designed and installed will not effect velocity, It can effect accuracy and Point of impact, because of the difference in weight that can change the barrel harmonics. and if it is cast and/or the opposing ports/holes are precisely the same, it causes an imbalance of forces that can effect accuracy.
When a bullet leaves any firearm, the bullet velocity is at its peak and slows very little in the first few inches, the gas however instantly starts to slow rapidly because it has by nature, very little mass and therefor the bullet frees its self of any effect of the gas just like the bullet crown does.
If you watch any slow motion Video or a weapon being fired you will be amazed at how far the bullet is from the muzzle when the gas appears and also how far the bullet is when the recoil appears and the weapon starts to move.
More than anything port angles create more or less noise for the shooter or the spotter and have very little effect on Recoil. A well designed brake is the total combination of all the best choices with some compromises to reach a good balance for overall performance.
Our test showed that there were "NO" quite brakes. They all ranged from 105 DB to 108 DB with or without a brake. the Perceived noise was greatly changed depending on the type of brake and the position of the person. But the DB meter showed the level of noise to be within these ranges.
Each Load has its own bullet energy recoil and its own powder recoil potential The bullet recoil energy of any bullet can only be changed by changing the velocity or the weight of the firearm.
The Gas recoil is what the brake "Can" deal with and this is where the recoil reduction is found
when using a muzzle brake. But when dealing with any gas recoil the total recoil developed, cannot exceed the potential. (Example: If the total gas recoil produced is 60%, the recoil reduction can't be more than 60 % so somewhere under that number is where it recoil reduction will fall. This does not mean that the rifle recoil will be reduced by 60% because there is still the bullet recoil that has to be added to that.
Another example is the testing we did on the 50 BMG. the rifle produced a total recoil of 110.6 ft/lbs
of recoil without any muzzle brake. with the factory brake muzzle brake the rifle produced 77.1 ft/lbs of recoil for an efficiency of 30.2%. With the first Prototype, the total recoil reduction was 59.3 ft/lbs for a gas reduction of 60.5% of a possible 66.8% of the gas recoil. Once we figured out that tuning the brake for the most efficient gas management of the specific load we were able to get the efficiency to 98% for a total reduction of 41.3 ft/lbs of recoil. So from 110.6 to 41.3 ft/lbs recoil reduction made the 50 BMG pleasant to shoot.
The fact that a muzzle brake works based on the gas recoil limits the total amount of recoil you can expect from a cartridge and can't change anything else needs to be understood to take advantage
of what your Bullet to gas Ratio is to get the optimum performance from a brake.
The bigger/heavier the bullet, the lower the powder recoil and the higher the bullet recoil energy ratio will be reducing the total recoil potential of a brake. (If a bullet to powder ratio is 40;60, the most you recoil % you can get is below 60% of the gas recoil + the bullet recoil (Inertial).
I hope this is clear and explains what a muzzle brake really does and how it works despite all of the theories we have heard. I had plenty of ideas and misconceptions before we started to test and now I know the facts as the test have proven and I am comfortable with all of the results.
Sorry for the long post, but I don't like just making a statement without something to back it up.
Just the facts as I know them based on the extensive testing. If anyone is interested in looking at some of the Video testing, go to
www.jecustom.com - Home of the Assassin Muzzle Brake and look at the 8 Videos we have posted.
J E CUSTOM
Makes total sense. You can't effect the recoil energy of the projectile, but you can the gas recoil energy. Looking at it from the point of view that the bullet is just one particle in the stream of ejected particles, it makes sense that the gas particles never catch up since they have so little mass compared to the bullet. So all a muzzle brake has to work with is the gas portion of the total energy.
I will add that while the decibel level doesn't change the perceived "loudness" does change and so does the concussion felt by the shooter when you change the port angles.
I will disagree that changing port angles doesn't change the effectiveness of a brake. It most certainly does. I guarantee you that if a brake was made with all 4 or 5 ports at 30 degree back angle instead of 1 at 90 degrees and the rest at 30 degrees it will work better at reducing recoil. Even two brakes exactly the same except with different port angles. The brake with steeper port angles will reduce more recoil. A 5 degree difference won't amount to much but 15 degrees will be noticeable.
Anybody that has been around muzzle brakes for very long knows that you can't change the primary recoil (the acceleration of the bullet) with a muzzle brake. Muzzle brakes only work on secondary recoil which is the gas recoil as Jerry mentions. As bullet weights go up so does the recoil, as powder charges go up so does the recoil, and as rifle weight goes down the recoil goes up. The only good thing about powder charges increasing (except for the added velocity of course) is you have more gas recoil to use in a brake and it changes the percentages of primary and secondary recoil. That is why the more overbore a case is the higher percentage of recoil reduction you get with a brake. Also as I said before....as the bore size gets larger any brake loses effectiveness.
I will disagree that changing port angles doesn't change the effectiveness of a brake. It most certainly does. I guarantee you that if a brake was made with all 4 or 5 ports at 30 degree back angle instead of 1 at 90 degrees and the rest at 30 degrees it will work better at reducing recoil. Even two brakes exactly the same except with different port angles. The brake with steeper port angles will reduce more recoil. A 5 degree difference won't amount to much but 15 degrees will be noticeable.
Anybody that has been around muzzle brakes for very long knows that you can't change the primary recoil (the acceleration of the bullet) with a muzzle brake. Muzzle brakes only work on secondary recoil which is the gas recoil as Jerry mentions. As bullet weights go up so does the recoil, as powder charges go up so does the recoil, and as rifle weight goes down the recoil goes up. The only good thing about powder charges increasing (except for the added velocity of course) is you have more gas recoil to use in a brake and it changes the percentages of primary and secondary recoil. That is why the more overbore a case is the higher percentage of recoil reduction you get with a brake. Also as I said before....as the bore size gets larger any brake loses effectiveness.
J E Custom
Well-Known Member
There are several items that I would have to disagree with but to be fair I had much the same
beliefs before testing on a Autonomous test bed that did not care what kind of rifle or what style of brake was used. My theory was that the greater the port angle, the more back thrust it could develop and the more recoil reduction it could produce. we proved this to be wrong in testing two brakes with the same port volume and one with 60o port angles to the bore and the other 90o to the bore. much to my surprise the 90o brake performed better and had much less effect on the shooter a the spotter.
The problem we found with the angled ports being all the same was that the gasses were not managed and each port had its own signature creating separate shock waves and making the perceived sound and shock wave much greater. they also impacted the ground closer to the shooter
kicking up more debris.
I mentioned controlling/managing the gas more efficiently to minimize some of the negative effects
and we found that by allowing/designing the gasses to converge instead of all of them facing the same way they went farther away from the shooter and went subsonic farther away from the shooter making it more desirable to shoot and the perceived sound less. (But less desirable to your neighbor because the shock wave had more energy at distance).
The other thing we found was that none of the steep angled ported brakes exceeded 50 to 55% efficiency. most were 30 to 40% and that if you controlled the gasses to the optimum angle and converged them the efficiency went consistently from 60% to as much as 75% on some cartridges.
The other theory was that the bigger the bore the less efficient the brake could be. the real reason it proves true is the bullet to powder ratio is higher in the bullets favor increasing the inertial/bullet recoil with less powder to compensate for the increase in bullet weight. before testing, I thought it had something to do with the size of the bore hole allowing more gas to escape out the front making the brake less efficient. Turns out to be nothing more that the bullet to powder ratio that reduced the efficiency of the brake, not the bore size.
When I started trying to improve the design of muzzle brakes there was only "ONE" design that had tried to direct/control gas discharge (The muscle brake) And it was/is one of the best performers
tested. On some rifle/cartridge combinations so I was curious why it did not perform as well on other cartridges. The answer came when we discovered that "NO" brake design is efficient on all cartridges. So this is what lead to tuning a brake for optimum performance based on the cartridge
bullet to powder ratio. The down side to tuning, is that the brake has to be built for that cartridge
and load to reach 98 to 99% efficiently for the available gas.
Everything is important if you want to reach these efficiencies. Port volumes, angles, width, height, depth, number of ports, even the finish inside the brake has a large bearing on its ability to flow gases well.
I am glad to see some new designs appearing and the efficiency improving finally because at one time all that was required to make a brake was a piece of round stock with a bunch of holes drilled in it.
J E CUSTOM
bigngreen
Well-Known Member
This is making my brain smoke!! I've put on a lot of muscle brakes and love them because of how easy going for the shooter they are and the way we hunt the spotter is usually also dialing it beside the shooter and will be ready to send a second round if needed, the muscle brake is the only brake I've shot that I'm comfortable next to my buddy shooting, I get no concussion from his shot beside him.
Until I put a 5 port Muscle brake on Steves 338 LAI I was very happy with the result but it seems it's beating him like a read headed step child, I've use the 4 port on quite a few 338 RUM's and I'm free recoil them. I've seen the Pain killer brake work awesome and guys love it but I have one here one a 30-338 LAI that you actually built that I find miserable to shoot because of the concussion and the recoil reduction isn't what I'd call spectacular, I absolutely hate not having something working the best it could so this is really frosting my buns!!
