Recoil Reducers?

[Philip Glass]

Here we are. We all want to shoot big African or as we called them as children "Elephant Guns". We all want to do this and have the recoil of a .243. Thats not possible so what is possible? There are many recoil reducers but what actually works? I wish there was someone who would actually do a scientific study of the recoil reducers and measure exactly what they do in different guns. Why has no one done this? We all know our dads told us you could put lead shot in the stock to reduce recoil, now there are mercury reducers, Edwards which is hard to describe so I won't try, and Blaser has a tube filled with tungsten beads. Has anyone read anything that gives any direction on how much recoil can be tamed by such a device?
I have Edwards recoil reducers in something like 6 guns including .375 and .416 and I believe they work well and don't add weight. Most recently and quite effective is the one I put in my Tikka T3 7mm Mag. I am skeptical of the mercury and tungsten as are they primarily not just weight? Remember our dads put lead shot in the stock not too 2019ish kinda thing to do is it? Does anyone know what do they really claim the advantage is in the mercury or tungsten beyond the weight? Any data out there?
Regards,
Philip

 

[Shootist43]

I totally agree with the need for a scientifically based study on the subject. Hopefully some lead slinging Grad. Student will pick up the challenge. I don't want to speak for the rest of you guys but I'd be willing to "kick in" a few bucks to get this question answered once and for all.

 

[barbells.and.arrows]

I don't know about the other options out there for recoil reduction, but I've always had a dead mule (because dead mules don't kick) in all of my trap guns over the years, and while it does add weight, it does help take the recoil down. They claim 15% reduction in recoil. https://www.ballisticproducts.com/Dead-Mule-Recoil-Reducer-standard-model/productinfo/1510502/
Another option to consider wanting data from.

 

[steve white]

Interestingly, a recent airing of "Steve's Outdoor Adventures made comment that of all things--noise suppressors, actually reduced recoil. Since muzzle blast is almost as often implicated in flinching as strict recoil, it would seem to be two for the price of one. (Only downside being the hefty license fee for the suppressor.)

 

[BRICKBURN]

Everyone who has ever pulled a trigger shares anecdotal "evidence" on the net. Constant quotes of "I don't know the science, but it feels like ......"

Most of the "reducer ads" make claims of various successes.

There are a couple of science articles Mechanical Engineering. I'm sure there are more to be found.
The one article funded by Weatherby attempting to measure/test recoil should have some research leads for you.

It appears that "Time" (and possibly Angular Momentum? or a combination) is a very real factor in the Stock media insertion (Mercury, Lead, Tungsten.) and its success in addressing felt recoil. So, it's not just the weight.
(This made sense to me when I think about my experience between the 300 Win Mag and the 375 H&H.) I'd love to measure the "time profile" of the recoil of these two rifles and see if it fits the "felt" experience. eg. Sharp vs a push.

https://www.physicsforums.com/threads/physics-of-firearm-recoil.921231/

https://www.researchgate.net/publication/269285669_Recent_Advances_in_Small_Arms_Recoil_Reduction

https://digitalcommons.calpoly.edu/...le.ca/&httpsredir=1&article=1206&context=mesp


"Momentum Conservation
Momentum characterizes an object's resistance to change in motion. If this is motion along a straight line, we call it linear momentum; if it is rotational motion we call it angular momentum. The basic idea is the same: moving things like to keep moving, and to change their motion we have to apply a force. If no force is present, then momentum doesn't change, ie. it is conserved."


"Can you in general store the recoil internally and transfer it to the frame and handle over a slower period of time?"
"So the only variables would be in how the gas is directed and the time profile of the recoil force."



Happy research.

 

[slam8031]

I’m shooting silencerco harvesters suppressors on two hunting rifles. There is less recoil and muzzle rise that reduces angular momentum and my children (young daughters) are able to manage larger calibers because of them.

 

[Philip Glass]

Interestingly, a recent airing of "Steve's Outdoor Adventures made comment that of all things--noise suppressors, actually reduced recoil. Since muzzle blast is almost as often implicated in flinching as strict recoil, it would seem to be two for the price of one. (Only downside being the hefty license fee for the suppressor.)

Yes that’s why I have my 12 year old son shooting an Omega suppressor on his .308. Works quite well.
Philip

 

[PHOENIX PHIL]

Conservation of Momentum is the key to understand recoil reduction.

Momentum which I'll use the variable "p" is defined as such: p = m * v where m is mass and v is velocity.

There is momentum due to the bullet and gasses behind the bullet exiting the barrel. This momentum as an equal and opposite effect on the rifle. In other words the two momentums are equal in magnitude but opposite in direction. The latter is critical to understand, there is direction associated with the momentum as dictated by the velocity term in the equation.

So lets call the momentum of the bullet and gasses p1, and the resulting momentum of the rifle p2.

p1 = p2 in magnitude, direction is opposite

Weight Effect
p1 = m1 * v1 : m1 is mass of bullet and gasses, v1 is velocity of bullet gasses
p2 = m2 * v2 : m2 is mass of rifle, v2 is velocity of rifle

m2 * v2 = m1 * v1 : solve for v2

v2 = m1 * v1 / m2 : If you add weight to the rifle, increasing m2, v2 must be smaller in magnitude. Slow the rifle down and you will reduce felt recoil


Muzzle Brakes
This is where the appreciation for momentum having directions comes into play. The momentum in the bullet is something that cannot be reduced unless you slow the bullet down with a reduced load or shoot a lighter bullet. You also cannot reduce the momentum of the gasses unless again you reduce the load. But what you can do is redirect the gasses. Most muzzle brakes I've seen have holes perpendicular to the barrel and spread evenly around the entire barrel.

This allows for the gasses to escape in a new direction which changes has the effect of reducing the momentum that is in the same direction as the bullet. This in turn results in less momentum in the rifle in that same direction which is in the direction of the shooter.

By evenly distributing the holes in the muzzle brake, you have the effect of the gasses canceling each others momentums out in those other directions.


Mercury Recoil Reducers and other Mechanical Types
We have to now also account for conservation of energy. With the mechanical type reducers there is a transfer of energy into the reducers, specifically kinetic energy, which means something is moving. There that be a weight at the end of a spring or mecury sloshing in a tube, it does not matter.

By taking some the energy away from the rifle in recoil and the movement providing momentum to the reducer, you remove some of the momentum from the rifle.

This is a little harder to envision in your mind, but it's similar to the slide on an automatic pistol or the bolt on a semi-auto rifle or shotgun. The movement of the slide/bolt in those weapons means less energy/momentum in the rest of the weapon that is in contact with the shooter. And thus less felt recoil.


As to which one is best, that's a hard question to answer. While it's quite easy to quantify mass and velocity, it's quite difficult to quantify "felt recoil".

 

[BeeMaa]

I have mercury recoil reducers in a few of my rifles.
What I would like to see is a comparison like this video with mercury vs mechanical vs lead vs tungsten.

 

[PHOENIX PHIL]

I have mercury recoil reducers in a few of my rifles.
What I would like to see is a comparison like this video with mercury vs mechanical vs lead vs tungsten.

That’d be fun

 

[Bruce]

I like the recoil.. keeps me awake!!

 

[Shootist43]

BeeMaa, my thoughts exactly. That would show the "relative" differences if any, even though it may not be measured in "foot pounds" of free or felt recoil. I tried looking up the device used on Terminator Products Website but didn't see it. Perhaps one of our buddies in NZ could talk to them about doing such an experiment. I.E. identical rifles and loads except for the type of recoil reducing element employed. Von Gruff, do you hear your phone ringing or name being called?

 

[BeeMaa]

I tried looking up the device used on Terminator Products Website but didn't see it. Perhaps one of our buddies in NZ could talk to them about doing such an experiment. I.E. identical rifles and loads except for the type of recoil reducing element employed. Von Gruff, do you hear your phone ringing or name being called?

I tried looking it up as well, same results as you.
They make muzzle breaks and created this contraption to show how adding one makes a difference.
I'm not a fan of the muzzle break, but I do like to use a suppressor which does reduce the recoil.

 

[375 Ruger Fan]

Conservation of Momentum is the key to understand recoil reduction.

Momentum which I'll use the variable "p" is defined as such: p = m * v where m is mass and v is velocity.

There is momentum due to the bullet and gasses behind the bullet exiting the barrel. This momentum as an equal and opposite effect on the rifle. In other words the two momentums are equal in magnitude but opposite in direction. The latter is critical to understand, there is direction associated with the momentum as dictated by the velocity term in the equation.

So lets call the momentum of the bullet and gasses p1, and the resulting momentum of the rifle p2.

p1 = p2 in magnitude, direction is opposite

Weight Effect
p1 = m1 * v1 : m1 is mass of bullet and gasses, v1 is velocity of bullet gasses
p2 = m2 * v2 : m2 is mass of rifle, v2 is velocity of rifle

m2 * v2 = m1 * v1 : solve for v2

v2 = m1 * v1 / m2 : If you add weight to the rifle, increasing m2, v2 must be smaller in magnitude. Slow the rifle down and you will reduce felt recoil


Muzzle Brakes
This is where the appreciation for momentum having directions comes into play. The momentum in the bullet is something that cannot be reduced unless you slow the bullet down with a reduced load or shoot a lighter bullet. You also cannot reduce the momentum of the gasses unless again you reduce the load. But what you can do is redirect the gasses. Most muzzle brakes I've seen have holes perpendicular to the barrel and spread evenly around the entire barrel.

This allows for the gasses to escape in a new direction which changes has the effect of reducing the momentum that is in the same direction as the bullet. This in turn results in less momentum in the rifle in that same direction which is in the direction of the shooter.

By evenly distributing the holes in the muzzle brake, you have the effect of the gasses canceling each others momentums out in those other directions.


Mercury Recoil Reducers and other Mechanical Types
We have to now also account for conservation of energy. With the mechanical type reducers there is a transfer of energy into the reducers, specifically kinetic energy, which means something is moving. There that be a weight at the end of a spring or mecury sloshing in a tube, it does not matter.

By taking some the energy away from the rifle in recoil and the movement providing momentum to the reducer, you remove some of the momentum from the rifle.

This is a little harder to envision in your mind, but it's similar to the slide on an automatic pistol or the bolt on a semi-auto rifle or shotgun. The movement of the slide/bolt in those weapons means less energy/momentum in the rest of the weapon that is in contact with the shooter. And thus less felt recoil.


As to which one is best, that's a hard question to answer. While it's quite easy to quantify mass and velocity, it's quite difficult to quantify "felt recoil".

@PHOENIX PHIL : You need one of these Tee Shirts! One of my daughters gave me one for a Christmas stocking stuffer.

 

[PHOENIX PHIL]

@PHOENIX PHIL : You need one of these Tee Shirts! One of my daughters gave me one for a Christmas stocking stuffer.


View attachment 261599

@Royal27 woukd agree

 

[Royal27]

@Royal27 woukd agree

Very much so! LOL

 

[PHOENIX PHIL]

Very much so! LOL

Pee too!

 

[One Day...]

I will re-post here the substance of what I posted in the original thread where Philip asked the question first:

Recoil reducers use a moving mass (either liquid i.e. mercury, or solid i.e. tungsten, lead, etc. beads) and rely on both passive mass and dynamic effect to reduce recoil.

Passive mass is pretty obvious and amply documented. More mass to move absorbs more energy. The classic rule of thumb is that increasing gun weight by 10% decreases free recoil by 10%. Simple. Proven. Countless generations have increased mass with thicker barrel contour, lead bars in the fore end and rear stock, or lead shot/epoxy poured into the rear stock hole of shotguns and rifles alike.

The dynamic effect goes as follows: because the mercury or beads are loose in the reducer cylinder, but the reducer is attached to the gun, the cylinder recoils with the gun, while the mercury or beads first do not recoil but stay in the same absolute position in space until the front of the cylinder slams into them and the recoil momentum is opposed by this collision with an immobile mass. After the initial dynamic effect, the mercury or beads act as additional passive mass being moved back by recoil.

It seems that this may yet be a different effect from the effect of a slide moving rearward on a semi-auto as discussed by PHOENIX PHIL and as obviously effective in absorbing some of the recoil momentum.

Clearly, parts that can move on a gun, like a scope not tight enough in its rings, or ammo in the magazine, will "move forward" during recoil. More accurately they stay immobile in space while the gun recoils, which means that they "move forward" relative to their initial position on the gun, and they exert a forward force if their inertia is captured by the gun that is in rearward motion.

There is plenty of anecdotal evidence. Remember the very long Unertlt and Leatherhood target scopes that were purposefully sliding forward in their mount to avoid recoil damage? Or, today, notice the bullet makers putting polycarbonate tips on their bullets to prevent damage to exposed lead points in the magazine under recoil? Or have you read Peter Capstick telling in one of his books how he almost got killed by constantly topping off his .458 magazine and allowing the bullet of the bottom cartridge to be pounded back into its case by cumulative recoils, and developing fantastic over pressure when he finally fired it?

There was a 'study' some years back. If memory serves, jury-rigged field tests apparatus (recoils sleds) contrived for the 'study' (I would call it "empirical test") were inconclusive at detecting a difference between a 2 lb lead rod and a 2 lb mercury recoil reducer.

My take is that because the math is never wrong, I understand that there IS an additional dynamic effect with the moving mass recoil reducers, but its actual contribution to recoil reduction may be so small as to be undetectable by anything other than finely tuned laboratory equipment... notwithstanding the fact that the placebo effect is alive and well ;-)

As to suppressors' effect on recoil, that is much more simple and clear cut. They act exactly like muzzle brakes. They trap gases that are moving forward, therefore they capture a forward momentum that negates some of the rearward recoil momentum. Like with the brakes, the 'bigger' the cans are, the more gas they trap and the more recoil they negate (assuming proper design). A brake is deafening because it redirects in real time and at full speed the gases rearward toward the shooter (or at least sideways), and a can reduces noise because it delays and slows down the ejection of the gases forward.

 

[Ray B]

There are two stages of recoil. Most of the equations attempt to measure the second stage which is after the bullet has left the barrel. the primary recoil is while the gun is a closed system and maintains a specific point of balance. If you have a method of setting your rifle at its balance point, do so as the rifle would be prior to firing, loaded magazine and chambered cartridge. If you want to be particularly safe, do this with dummy rounds but the bullets must be of the same weight as what you'll be shooting. Note the point on the rifle that is the exact balance point. Then empty the chamber and insert a case that contains no bullet but has 1/2 the powder charge in it. At the end of the barrel attach the bullet and 1/2 the weight of the powder charge. What you are simulating is the position of the elements at the last moment the bullet is in the barrel. This will have a different balance point for the rifle. Depending on the weight of the bullet and the relative weight of the rifle, the shift in the balance point will move a distance toward the muzzle. Note the distance between the two balance points.

Now note the muzzle velocity of the cartridge involved. To find an approximation of the average velocity in the barrel, divide the MV by 2. If the MV/2 is in feet, multiply by 12 to change to inches. Then divide the result by the distance the base of the bullet travels (in inches) from the chamber to the muzzle. This will give you the amount of time that the shift in balance will have taken. You will see the distance the rifle will want to travel and the time it will take for the trip. Divide the distance travelled by the rifle in the balance points by the amount of time it took and you will get the speed of the recoil.

As noted, this is the primary step of recoil. there is additional recoil generated by escaping gases and inertia effects, but this calculation will give a comparative measure and show why bullets that exit the barrel quickly may have a sharper "slap" and heavier slower bullets will have more of a "push".

 

[crs]

My Winchester 1886 45-90 came with a dual recoil control system-
Weight and curved steel buttplate:

Never a bruise or cut when mounted correctly.
Of course my kids learned on an 1892 .357 magnum with same results:


Physics is simple until you reach the nuclear and quantum levels.