Can switching muzzle brakes change muzzle velocity??

[WildRose]

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!!

Engineering can only do so much when you have that volume of powder burning and exiting a .338 hole HA!

As for perceived noise its all about how the shooter perceives it. Think about a megaphone, it doesnt make your voice any louder or more quiet, it simply directs all of it at a narrow angle to the front so that someone standing right behind you will not hear the same volume of noise someone out in front of you will.

The way brakes channel gasses directionally is the same way in which they project noise.

Unfortunately the brakes that direct the most of the blast to the rear are those that will have the sharpest rapport to the shooter and with the big boomers the blast wave can really be physically punishing.

Theres going to be a trade off between noise and recoil reduction (again as the shooter perceives them) and those that are easiest on the shooter are going to be pretty nasty for anyone out to their sides.

Having shot dozens of different designs of MBs over the years and the best ones Ive tried rely on multiple ports of different sizes and slightly different angles on the ports such that the rear port somewhat cancels out the blast from the ports in front of it by being larger and angled slightly forward while the rest are angled slightly backward and smaller.

 

[RockyMtnMT]

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!!

I opened the first baffle on the Muscle break and shot it yesterday. Shot it with a 30-06 and 180g bullets un braked, and a 375 Cheytac with 394g bullets. My rifle was by far the heaviest recoiling rifle. The 375 you needed to have your stuff together to shoot. My rifle plain hurts. Made Brian shoot it just to make sure I was not a *****. All he said is that that thing has got to go. Then bitched about how his shoulder was hurting. This 5 port Muscle brake was a mistake. I will never cut a corner again.

Steve

 

[IdahoCTD]

I guess we will agree to disagree on many points then. On my sled the Muscle brake doesn't do well at reducing recoil. Does it reduce the concussion...yes but it is no where close to the best at reducing recoil. It's actually one of the worse performing brakes at reducing recoil of the dozen plus brakes I've tried, and I tried the 5 port version against mostly 4 port brakes. Guess which ones do the best? The brakes with the steeper ports typically do the best.

I do agree that converging the gases will definitely reduce the perceived muzzle blast or concussion. I also agree that one brake design isn't ideal on every rifle, there is no way it can be. I will also agree that if the bore size increases and the primary to secondary recoil relationship changes it will effect the performance (it happens on every caliber not just big bores). The same brake used on a 6.5mm and a .45 caliber won't perform the same even if the primary to secondary recoil percentages are the same. I know you use a much larger brake on 50BMG's then a 300RUM so you know that.

To be fair JE you just haven't tested the best of the best brakes out there. Comparing yours to the Muscle brake doesn't tell you much if that is the most effective brake you've tried.

I started off making brakes 25 years ago with that round stock and drill bit on a mill with a indexing jig. It's amazing how many are still made that way today and how those archaic designs still sell. I see custom rifles all the time with those same old drilled hole brakes from many years ago. The only difference is they are now made on a CNC for dirt cheap.

 

[Pdvdh]

On my sled the Muscle brake doesn't do well at reducing recoil. Does it reduce the concussion...yes but it is no where close to the best at reducing recoil. It's actually one of the worse performing brakes at reducing recoil of the dozen plus brakes I've tried,

Now maybe we're getting somewhere... Can you provide some brands/models of the muzzle brakes you've tested that reduce recoil better than... well... the average brakes??? Or better than the better than average brakes.

Which were the better ones you've tested? Maybe that's the politically correct question.

 

[bigngreen]

I opened the first baffle on the Muscle break and shot it yesterday. Shot it with a 30-06 and 180g bullets un braked, and a 375 Cheytac with 394g bullets. My rifle was by far the heaviest recoiling rifle. The 375 you needed to have your stuff together to shoot. My rifle plain hurts. Made Brian shoot it just to make sure I was not a *****. All he said is that that thing has got to go. Then bitched about how his shoulder was hurting. This 5 port Muscle brake was a mistake. I will never cut a corner again.


I'm just trying to understand the why, I've literally put dozens of the 4 ports on RUM's and LAI's and I shoot very loose and their pleasant, heck everyone want to keep shooting them, that's the first 5 port I've used and it's sucking and it should not IMO but other than the through holes not much a guy can do to change them. There is a 10 degree port difference, that isn't going to do much, one big thing I'm seeing is the way the PK is made and where it makes you put the crown it makes that first port have a lot of volume but not certain what that does. In some of the testing the Hollands Radial baffle brakes does very well and it's a straight port but the first port is larger than the rest, I've shot the JP coolie brake a lot and it's been nice on recoil and again first port is larger. But then you have the old Lawton design with a set of radial holes in a large port then a small port then larger ports and it seems good also, shot a lot of cheytacs with that one. I've put a small Muscle brake on a 300 RUM and it was a joy to shoot 230's from, and it's not that I'm tough about it, I'm a recoil wuss and I shoot very loose so any real recoil I at least get the scope hitting my hat.
It makes me wonder if the LAI is over powering the first baffle where the smaller RUM is more in tune for lack of a better term, don't know, definitely trying to learn and figure it out cause for me I dislike the PK as much as your disliking the Muscle, I have not tried JE's Assassin though he's obviously put a lot of work into actually understanding whats going on to the point of tuning a brake which I think says something, and one day I'll remember at a decent hour to call Nathan and get one of his.

 

[fiftybmg]

I believe it can, and I expect it to happen.

I'm not an expert in anything, but I've noticed a few things. This needs some explanation, so please be patient.

I once met a fellow rifle shooter who was a manufacturing engineer.

He told me that rifle recoil is not due to the projectile exiting the muzzle, it is a result of escaping gas. The recoil impulse is equal and opposite to the gas exiting the muzzle only.

He discovered this for himself when he had a shoulder injury and couldn't shoot his rifle, and so had to miss a hunting trip. Being a tinkerer, he looked at ways to reduce recoil, so he drilled holes in the last 2 inches of barrel before the crown, perpendicular to the bore axis, to see what would happen. Testing off his uninjured shoulder, his felt recoil was reduced, and he drilled more holes, reducing recoil to the point where he was able to shoot his rifle off his injured shoulder.

I laughed a him. I doubted him. I did a bit of reading. Now I'm not so sure he was wrong.

Muzzle brakes divert gas from exiting the muzzle crown. This has the effect of reducing felt recoil. If the muzzle brake does not divert gas from exiting the crown, the recoil effect is not reduced. The more gas is diverted from following the bullet out of the end of the muzzle, the less recoil is felt.

Why does muzzle velocity reduce when the muzzle brake is changed ?


If a muzzle break is on a barrel that is just optimal length, where combustion is nearly complete before the bullet exits the crown, changing the brake will change the point at which the gas begins to exit, changing the pressure generated in the barrel, which will change the velocity.

Bullet velocity is proportional to the amount of gas generated by the powder. Less burn means less velocity. In long barrels, it is possible for powder to completely combust before the the bullet has exited the muzzle. Then the extra inches only serve to put drag on the bullet, reducing velocity.

The scientific method to verify this would be to plot velocity against barrel length for a given load, and progressively reduce the barrel length. And it has been done, Google for it.


To explore the theory of gas causing recoil, not bullet weight or bullet velocity, Youtube for some super slow videos on a shot being taken. You will see that the recoil impulse begins not only after the bullet has exited the barrel, but only when the gas is exiting. The period between the exiting of the bullet to the exiting of the gas shows no recoil impulse.

If the recoil was due to the laws of conservation of momentum of the bullet, recoil has to begin after the primer ignites, because the bullet can't move faster than the laws of physics.

These observations imply that the most efficient form of muzzle brake is one that is barrel integral. This means that the rifling continues through the "brake" section - holes are drilled in the barrel perpendicular to the bore, in the grooves of the rifling, leaving the lands intact. If the holes are not perpendicular, there will be a velocity component of the gas producing recoil along the bore axis.

 

[IdahoCTD]

Now maybe we're getting somewhere... Can you provide some brands/models of the muzzle brakes you've tested that reduce recoil better than... well... the average brakes??? Or better than the better than average brakes.

Which were the better ones you've tested? Maybe that's the politically correct question.

The best brakes I've tested are the 5 port Terminator brake, my 4 port Beast brake, and the 4 port Fat Bastard for the top 3 in that order. That is both on a 300wm and a 338 Lapua. You start to see many brakes cluster together when you get down to the less effective brakes. If you look at the PRS results the Fat Bastard is the top brake so that will kind of give you a idea of where the Terminator and my brake lands.

I'll probably go out tomorrow or Wed. if it isn't raining and test some other size brakes plus shoot one rifle through the chronograph on and off the sled to prove the velocity doesn't change if the rifle is allowed to slide on my sled. I will run through brakes from .750" to 1" or so on a 300wm to show the difference the sizes make also.

 

[J E Custom]

This has turned into quite a discussion, (I like it because it gets people to thinking).

I under the smoking brain, (I had the same condition at one time). also when I started testing
I bought and tested all of the premium muzzle brakes I could find. I used many of them and wanted to see if it was a waste of time to try and improve on them, so there was a good comparison.

As stated early in this thread. ALL MUZZLE BRAKES WORK THERE BEST ON ONE CARTRIDGE.
they Will not produce there best on every cartridge. (The reason is the amount of gas they have to deal with. and there design.

Depending on the cartridge and load, A 4 port may work better than a 5 port of the same brand with the same port size. for the smaller cartridges, the 4port is probably the best choice. But for the biggest cartridges the 5 port should handle more gas so it would be the most likely to perform.

In Hatchers Notes, he mentions trying up to 9 ports to see if there was a perfect number and discovered that somewhere between 4 and 5 ports of the correct size produced the best results.(Optimum). Kind of like barrel length.

I know it is frustrating but Just because a brake works well on one rifle, doesn't mean it will work well on another. This is where tuning for a specific cartridge comes in. So with the aftermarket brakes being identical in there design, there is no way they will produce there best on all rifles/loads

Tuning can only be done on a custom built brake and therefore is impractical. even if the manufacture Made brakes for each cartridge, The re loader would have to match the factory load to get the best performance.

So, If one brake doesn't work as well on one rifle as it does on another, don't be surprised. There are many things that can effect the performance Plus or Minus.

There will always be theories and beliefs about how brakes work . Only testing will prove how they actually work. so don't beat your self up buy a brake and try it, If you like it Be happy. If you don't try another.

J E CUSTOM

 

[WildRose]

I believe it can, and I expect it to happen.

I'm not an expert in anything, but I've noticed a few things. This needs some explanation, so please be patient.

I once met a fellow rifle shooter who was a manufacturing engineer.

He told me that rifle recoil is not due to the projectile exiting the muzzle, it is a result of escaping gas. The recoil impulse is equal and opposite to the gas exiting the muzzle only.

He discovered this for himself when he had a shoulder injury and couldn't shoot his rifle, and so had to miss a hunting trip. Being a tinkerer, he looked at ways to reduce recoil, so he drilled holes in the last 2 inches of barrel before the crown, perpendicular to the bore axis, to see what would happen. Testing off his uninjured shoulder, his felt recoil was reduced, and he drilled more holes, reducing recoil to the point where he was able to shoot his rifle off his injured shoulder.

I laughed a him. I doubted him. I did a bit of reading. Now I'm not so sure he was wrong.

Muzzle brakes divert gas from exiting the muzzle crown. This has the effect of reducing felt recoil. If the muzzle brake does not divert gas from exiting the crown, the recoil effect is not reduced. The more gas is diverted from following the bullet out of the end of the muzzle, the less recoil is felt.

Why does muzzle velocity reduce when the muzzle brake is changed ?


If a muzzle break is on a barrel that is just optimal length, where combustion is nearly complete before the bullet exits the crown, changing the brake will change the point at which the gas begins to exit, changing the pressure generated in the barrel, which will change the velocity.

Bullet velocity is proportional to the amount of gas generated by the powder. Less burn means less velocity. In long barrels, it is possible for powder to completely combust before the the bullet has exited the muzzle. Then the extra inches only serve to put drag on the bullet, reducing velocity.

The scientific method to verify this would be to plot velocity against barrel length for a given load, and progressively reduce the barrel length. And it has been done, Google for it.


To explore the theory of gas causing recoil, not bullet weight or bullet velocity, Youtube for some super slow videos on a shot being taken. You will see that the recoil impulse begins not only after the bullet has exited the barrel, but only when the gas is exiting. The period between the exiting of the bullet to the exiting of the gas shows no recoil impulse.

If the recoil was due to the laws of conservation of momentum of the bullet, recoil has to begin after the primer ignites, because the bullet can't move faster than the laws of physics.

These observations imply that the most efficient form of muzzle brake is one that is barrel integral. This means that the rifling continues through the "brake" section - holes are drilled in the barrel perpendicular to the bore, in the grooves of the rifling, leaving the lands intact. If the holes are not perpendicular, there will be a velocity component of the gas producing recoil along the bore axis.

Pardon the pun but there are a lot of holes in your theory here.

The firing of the bullet causes the mass of the bullet plus the pressure exerted against it to cause the rifle to recoil backwards.

This makes up about 40% or less of felt recoil. The only way we can reduce this portion of recoil forces is to shoot lighter bullets and/or lower volumes of powder resulting in reduced velocity loads.

The balance of recoil forces come from what I term the rocket motor effect. The gases exiting the barrel push the rifle backwards in the same way a rocket motor powers a rocket.

The latter is what is affected by a muzzle brake. The bullet has already exited before any serious amount of gas escapes the barrel and thus any effect the brake has on MV has to be minimal at best.

The manner in which and volume of these escaping and expanding gases are directed by the brake determines how much felt recoil is reduced.

Real world testing of MBs shows some to reduce felt recoil up to 70% and will also determine how loud the rapport is to the shooter and those around him/her. The most effective brakes tend to channel those gasses in large part back towards the shooter and in doing so also direct much of the muzzle blast.

The reason suppressors are so effective in reducing recoil is because they allow those gasses to expand in a large (relatively) large contained area and then escape at much lower velocity following the exit of the bullet. This is why the best suppressors will reduce felt recoil by around 70% as well. Unlike the brake however this large volume of trapped gas exerts pressure inside the barrel such that it can have a negative effect on gas operated semi auto systems which is why it is important to put an adjustable gas block on them.

 

[WildRose]

This thread got me looking around and I found a really good series of articles in which the author did some testing of various muzzle brakes measuring felt recoil, noise, and which of them best helped to keep the shooter on target.

I found them all to be worthy of the time it takes to read them.

http://bulletin.accurateshooter.com/2015/07/muzzle-brake-comparison-test-by-precision-rifle-blog/

 

[WildRose]

This has turned into quite a discussion, (I like it because it gets people to thinking).

I under the smoking brain, (I had the same condition at one time). also when I started testing
I bought and tested all of the premium muzzle brakes I could find. I used many of them and wanted to see if it was a waste of time to try and improve on them, so there was a good comparison.

As stated early in this thread. ALL MUZZLE BRAKES WORK THERE BEST ON ONE CARTRIDGE.
they Will not produce there best on every cartridge. (The reason is the amount of gas they have to deal with. and there design.

Depending on the cartridge and load, A 4 port may work better than a 5 port of the same brand with the same port size. for the smaller cartridges, the 4port is probably the best choice. But for the biggest cartridges the 5 port should handle more gas so it would be the most likely to perform.

In Hatchers Notes, he mentions trying up to 9 ports to see if there was a perfect number and discovered that somewhere between 4 and 5 ports of the correct size produced the best results.(Optimum). Kind of like barrel length.

I know it is frustrating but Just because a brake works well on one rifle, doesn't mean it will work well on another. This is where tuning for a specific cartridge comes in. So with the aftermarket brakes being identical in there design, there is no way they will produce there best on all rifles/loads

Tuning can only be done on a custom built brake and therefore is impractical. even if the manufacture Made brakes for each cartridge, The re loader would have to match the factory load to get the best performance.

So, If one brake doesn't work as well on one rifle as it does on another, don't be surprised. There are many things that can effect the performance Plus or Minus.

There will always be theories and beliefs about how brakes work . Only testing will prove how they actually work. so don't beat your self up buy a brake and try it, If you like it Be happy. If you don't try another.

J E CUSTOM

I think there's a lot of wisdom in this post. Every time you change bullets, powders, or volumes of powder you are going to change felt recoil to some degree with any muzzle brake, suppressor, or in the absence of either. You may simply have to experiment with several to find one that best fits what you are shooting.

 

[Timber338]

I'll do some more testing to see if I can find what caused my velocity drop, but overall this is great discussion. I've learned a lot, thanks to all of you guys sharing your experience.

Just on the two brakes I had on my rifle, it seems like total overall port volume is what sets the Terminator T3 apart from the 4-port muscle brake. A part of my reasoning for the switch was to just get more experience with a different brake and learn something new. I only have a couple of rifles and I'm not a gunsmith, so I do what I can and certainly take advice from all of you, so I certainly do appreciate all of tue discussion.

JE's discussion of how you can tune a brake and how a single brake is not ideal for all cartridges got me to thinking (smoking brain). I wonder how my personal rifle effects the efficieny of any particular brake. I've got a 27" barrel shooting a 300 grain bullet with 93.0 grains of RL-33. I don't have quickload, but I'm wondering if I'm blowing some unused powder out the barrel? Again I don't have much experience with brakes, but from examining my 4-port brake that has about 300 rounds through it, there is quite a bit of pitting around the rear facing surfaces of each port near the bore.... possibly unburnt powder hitting the metal or is this just normal for any brake from exhaust gas? Just some observations, and overall there are so many variables at play with any particular rifle, just like Wildrose just mentioned.

Tuning a brake sure sounds cool, I would like to learn more about how that works some day.

Here's the 4-port side by side with the T3. Both great brakes in my book.

 

[Timber338]

A top view that I think really shows the difference in total useable port volume.

 

[WildRose]

Which of those two do you find gives you the best felt recoil reduction?

Just looking at the angles of the Terminator ports I would tend to guess it gives you the best recoil reduction but at the expense of a lot of added noise and blast.