Home Forums Hunting & Shooting Ask The Gunwriters Muzzle brakes.

Some interesting “physics” being discussed here.

Bottom line is that the gases being ejected from the muzzle at ~10k psi contribute cumulatively and non-negligibly to the recoil at the butt of the rifle during the time frame that we register in our brains as the recoil event. Redirecting the force vector of the accelerating gas at a steeper angle from the axis of the bore results in a substantial enough reduction in recoil to be noticeable.

Experiments clearly show this.

I'm going to resort to crayon-eating here.

No muzzle brake on lightweight 300WM = ouchie

Muzzle brake on lightweight 300WM = no ouchie!

I took English in college so I'll leave the quik mafs to the smart people.

I think it was Precision Rifle Blog-- interviewed David Tubb on his 33xc and asked him about compensators, Well I don't know so much recoil reduction, but sight recovering is, and that's why I use them.

Math models of systems are not meant to explain the complete event, but to examine it in depth from one specific view point.

just as the slide rule was replaced by the TI, the TI has been replaced by Matlab. (don't have to write a bunch of do-loops)

this also applies to the historical use of time as the basic point of view, with computers it is possible to compare the derivative of one process against another, or the phase diagrams/plots in the x,y,z plane. this brings out information about the process that cannot be seen with continuous curve processes (Calculus ex. )

Keep in mind chaos is not random, but order on different levels. after the gases leave the barrel the system is no longer "linear"
the barrel time isn't linear either if the time interval is made smaller.

as the volume of the gas increases, the temp. drop. with a drop in the pressure , and the momentum of the atoms is the gas.

another question to ask yourself --- is the "burning gases" coming out of the barrel so adamantly posted in the advertising nitrates form the combustion process, or low energy of methyl cellulose, and additives, contributing very little to the total.

“Do loops” shades of Fortran! 😳

say a .308 barrel 24in has a volume of pi*r2x24. of .07 cubic in. (if telephone calculator is correct)

and the pressure has gone from 60000psi to 20000 psi in just .07 cu in. change in volume or a reduction of 3 times.

now the Combined gas law. pv/t=p'v'/t'

what would it be the pressure drop if it changed from 20000 psi to a distance of 1 in from the end? The volume of 1 cubic inch. or roughly 10 times the volume working in 3 dimensions here.

what would be the pressure drop if it changed from 20000 psi to a distance of 2 in. from the end? 20 times---- no the volume
2 times 2 times 2 is 8, so volume change from .07 to 8 cubic inches. or 80 fold increase

assuming the temp stays the same- pv=p'v' or 20000/10=p or 2000 psi

and 20000/80= 250 psi.

say the first baffle in a comp was 1 in an 2 in for the second.

please check my math.

I thought I would post a couple of quick and dirty calculations to compare the recoil force generated by accelerating the bullet to 3000 fps versus the recoil force imparted by the hot gas molecules exiting the muzzle at 10k psi.

Assuming a simple model of accelerating a 180 gr 7mm bullet uniformly from rest to 3000 fps over 1.5 ms, the resulting force is ~7100 N. Assuming 65 gr of powder is converted to gas molecules that retain 10k psi at the muzzle when the bullet exits, and those molecules accelerate (decelerate) until they are at atmospheric pressure, the resulting force is 3588 N. Roughly and simplistically, the accelerating gas at the muzzle generates about 1/3 of the total recoil felt during the sequential recoil event. If it were possible to completely redirect those gases radially outward from the bore axis (e.g., 100% efficient radial brake), it would be possible to reduce recoil by about 1/3. If those gases then collide with brake baffles and transfer momentum, recoil gets reduced even further. These approximate numbers seem to be corroborated by experimental results showing that brake efficiency can vary in recoil reduction from about 20-40%.

For anyone interested in a more in-depth analysis, this peer-reviewed paper is a reasonably straight-forward read: https://www.sciencedirect.com/science/article/pii/S2214914718300758

Great article thanks, got to get into it deeper. Only impression at this time -- that break design is going to plug up pretty fast.
and they use the universal law pv=uRT which give the concentration which gives, mu the concentration and R the work constant. instead of the much simpler pv/t=p'v'/t' of the general form.

I didn't see any qualifiers as to how much the brake wt decreased recoil. and have to go back to see why.

JP brakes use a second baffle with surface area about 3 times the first to get the radial effect as described in your post

Couple of things in article interesting --mostly same claims as other makers/writers.

From the diagram the device uses the same bore size to move the gases from the end of the barrel through the device. Most current devices use an expansion chamber just after the barrel, ( sometimes up to 3 with a baffle separating each) which increases the volume/lowers the momentum. This brake ports them directly then redirects them at a 90 deg. angle. Good luck, might work with a .223. During the 80s this difference was a big deal and the expansion chamber lead to the differences in nomenclature --- compensator vs. brake.
This brake design would definitely work , but as a vaguely recall this type was introduced a long time ago but the military rejected it because of fouling and went with the flash suppressor type.

Keep in mind that no machine operates at 100% efficiency, so after the grain of salt, the paper calculates the Newtons and stuff from Classical Physics.
Also any type of device is going to work best with things like light wt. varmint loads because the ratio of powder is higher,
243 with 40-50 gr and and 40 grs. powder a 50/50--- not where its really needed 45 ACP with 5 grs. powder and 230 gr.

As Mr. Jordan pointed out, and the time frame is so small the human mind can't separate the different components,


But MY cheek sure can!

There addition of a tuner is interesting but not new.

When Browning came out with their Boss system, I got one on a 308. can't remember the model late 90s,
the entire gun was pretty advanced , the stock was like the current McMillian LRP stocks, barrel 26"

The device/break/brake/compensator was adjustable and you could tune it to your loads.

I never could tell much difference in reloads, but military surplus. WOW. It had a index for repeatable, and on setting good with LC didn't work for Portgugese , and vice versa.

Only problem--- surplus rarely gave sub moa groups anyway, but on the wrong setting they went to 4 in.

Interesting...
Did you ever swap out the muzzle brake tuner for the CR version to see how much the brake version reduced recoil? I did with a 7mm Rem Mag and the difference was noticeable.

The was one major problem with the BOSS system, and a secondary one:

Once you got the BOSS tuned with a specific load, it could get "untuned" if the temperature changed considerably--or even if a clean barrel tended to foul. If you used it fairly consistent temperatures, and kept the barrel clean, it definitely worked.

The second was that the brake was one of the loudest I've ever encountered. This could of course be dealt with in various ways, but like others who've posted here I'm not fond of brakes in general.

I found it easier to handload with temperature-resistant powders, but then I live and do most of my hunting in Montana, which has the highest recorded range of temperatures in the 50 states.

No never tried that, with almost 2x the "rocket fuel".

While reading the article, my mind kept drifting back to Magna-Porting. Especially the none expansion chamber part, and the pros and cons. Then it drifted to the new Mesa, Christensen with regular barrel long barrel, McMillian stock copy, 6.5 on sale currently at Sheels for $950. Slap me.

The article had some interesting parts, glad they brought out the burned gas part constituents. 94% CO2 ex

It would be interesting to talk with some of the contributors and see what they shot, how much and where.

Today with more folks shooting long range and the larger volume cases, it would be nice to see as much effort put into barrel cooling. If I wanted to wait 5 min. between shots, I'd shoot trap.

Mind drift again, first MagnaPort- NikkoGolden Eagle 338 mag, beautiful wood. 1980s. Was on an antelope hunt in Rock Springs. Had to sit through a presentation by some guy by the name of John Burns, trying to sell a hunting camp in the Sun Light Basin area. Slap me really hard.

Muzzle Brakes... Suck.

Find lightest rifle/cartridge that you can shoot accurately from field positions and still kill the game you want, and quit thinkin' that cartridge selection has anything to do with the size of your dick.

Pussy.




GR