Thank you gunsandgunsmithing for this opportunity. I will for the community, give you the credentials you have asked for as not to be impeached. Also I have written a book on kinetic energy and how it applies to small arms. The most important part of that book is where kinetic energy comes from and how the velocity gets squared with in the classic statement: E = 1/2mv^2.
1-Over my life time I have owned 30 some rifles, 10 shotguns and 2 pistols. Currently I am building a Palma rifle as soon as I get my wife a new ski jacket. after the ski jacket I'm going to order a Tubb butt plate and a V block to mount a R700 short action. I picked up a cheap X40 stock from Gun Parts World in New York. I am new to 1000yard prone shooting. Also I am waiting for my Montana 1999 Professional Hunter Action to arrive. It should be here in February. I'm going to build a .460 Weatherby Mag.
2-Yes and No. Yes I have a ported choke for my 870. No I have no rifles with brakes on them. However, I am going to build a countersniper rifle from an old M98 action I have. This countersniper will be chambered in .338 Achilles. The Achilles is a RUM case shorten to 2.55†with 35 degree shoulders. I already shoot the 7mm Achilles. This new rifle will have a Score High muzzle brake called, “The Tactical Bolt.â€
3-Okay, first thing: kinetic energy is not a theory nor is how I apply it. Kinetic energy has been around for about 276 years and is establish and proven science,my book contains the mathematical proof for kinetic energy).
How dose a muzzle brake work,and I know you know how it works) and how is the energy transferred via muzzle ejecta to the brake,which you may not understand). Now work with me here. The full answer is about two pages long with some nasty mathematics. So I'm going to take some short cuts to put this in less than technical terms.
The powder charge within the cartridge is a chemical in a solid form. Most single base nitrocellulose powders contain about 175ft-lbf of energy per grain. Just like food has calories, 1cal = 3087ft-lbf). So just for back ground as Einstein said, “all energy is mutually convertible.†So we are going to convert the solid, chemical energy of the powder charge,56 grains of IMR4350) to a gas in the form of thermodynamic energy. That is done by dropping the hammer onto the primer.
Okay, we now have a 56 grains of powder that has converted to a hot compressed mass of gas at about 60,000psi. The gas expands about 2000 times plus another 500 times due to the heat of oxidization. That expanding gas is pushing in all directions. The gases push radial to the case body, sticking that case body to the chamber wall. The gases push to the base of the case transferring its energy to rear though the chamber walls,some and hopefully very little as bolt thrust and of course rearward case stretching), through the stock and into your shoulder. The gases push forward on the base of the bullet transferring its energy to bullet motion. I think you already understand this.
The pushing of the gas rearward is a calculable load as represented by the powder charge weight times its velocity. The pushing of the gasses forward is a calculable load as represented by the bullet weight times its velocity. The sum of the powder charge weight times its velocity and the bullet weight times its velocity divided by the guns weight will equal the velocity of the gun in rearward motion into you shoulder. So, gun weight times its velocity squared,just found by the sum of the powder charge and bullet) divided by 2 times the dimensional constant equals the foot-pound force of recoil.
So I think all the forgoing is no new news to you. Here is where it all gets tied together. The recoil of the gun is figure all the way up to the point where the base of the bullet exits the muzzle and the system is now open. All energies transferred as recoil energy are calculated and taken it account. The “jet effect†or “secondary recoil†is already accounted for in the original event of the energy transfer form the powder charge to the bullet and gun/shooter system.
The remaining energy that the bullet now possesses, may now be used to get it down range to the target. If that target is paper, any leftover energy is wasted and delivered to the impact area. In hunting that left over energy is delivered to the game animal; which is also a new and open sysytem.
The longer the barrel the greater the energy transfer from the expanding gases to the bullet and gun. Therefore, the greater the energy transfer the greater the bullet energy and recoil energy. However, any excessive expanding gases not used within the barrel is expelled into a new system and is waste product. This new system is called the atmosphere. We all know this extra stuff,waste product) as muzzle blast or muzzle ejecta.
So this is how a muzzle brake works. The wasted gases we know as muzzle blast are redirected through holes and or baffles in the brake and the wasted energies are recovered by the brake which is a mechanical device. As the gases hit the perpendicular walls of the holes and or baffles, the energy in a forward motion is transferred to the brake then to the barrel pulling the gun forward. The difference in the recoil energy of the gun minus the muzzle blast equals the felt,or net) recoil. You can use Le Duc’s equation to determine the waste muzzle ejecta. I will not take up your time explaining porting. It’s nearly the same thing. Just remember the first port within the barrel becomes your pseudo muzzle for the purposes of a calculation. In the simplest of terms, a muzzle brake is a sail. It is a mechanical device that captures a waste product’s energy and diverts it back into a system. There is no secondary event or recoil. This mechanical action happens exactly at the same time as everything else.
The recoil of a gun, felt recoil, bullet energy, thermodynamic energy, chemical energy, mechanical energy, brake enegy, kinetic energy is all the same thing. All of these energies are calculable as a measurement. Their true name as it pertains to objects in motion is called, translational kinetic energy and the measurement is in foot-pound force.
I thank you for this opportunity to explain recoil and muzzle brake dynamics.
P.S. its late and I'll will have typos. God bless you all.
NOTE:
An open system is when energy transfers from one system to another. Example: A Firearm; the energy of a powder charge is transferred to a bullet. When the bullet exits the muzzle,leaving the system) the bullet may now transfer its energy to a target,another system).
A closed system is when no energy transfers out of the system. Example: A Hydraulic Jack; via a jack handle the hydraulic fluid is pumped from the reservoir and small piston into a larger piston. The increasing pressure within the large piston then causes it to rises. When the bypass valve is opened the pressurized fluid is diverted away from the large piston back into the reservoir. The large piston now falls and descends. All energies say within the jack.