Powder choice/burn rate and recoil. How are they related, How do you predict or measure effect?

[dellet]

I'm pretty sure you can find the answer that you're looking for in QuickLoad. The bottom line is PRESSURE. The number that is circled in red.

Joe


View attachment 1032781

Sadly it’s not that simple, or I’m missing something very basic.

Two example loads, same 325 grain bullet. Quickload calculations.

42.3 grains of 5744
37897 psi
3948 psi muzzle pressure
2080 MV
27.3 pounds recoil
28.6 on the Barsness index (new word today)

61 grains 2230
36746 psi
4281 muzzle pressure
2085 MV
32.1 pounds recoil
30.2 Barsness index.

Less, faster burning powder, creating a higher peak pressure with a steeper rise and fall, results in an 8% drop in muzzle pressure and a 15% drop in pounds of recoil.

The Barsness index is a new question for me. Using that calculator there is only 5% difference measured.

If I am reading and interpreting numbers correctly, pressure at bullet exit has the most effect on recoil.

 

[CharlieNC]

Quick Load does include a recoil calculator in the "Options" menu heading. I haven't used it but it appears quite comprehensive.

 

[dellet]

Thought I would give a bit of an update. Lot's of info and suggestions here that helped me understand (I think) what happens and how to at least compare loads on paper, that should be more comfortable to shoot.

Most of the online recoil calculators really don't ask for enough information to give more than reasonable numbers to compare. Some of the better(?) online calculators ask for charge weight, case capacity. All this got a bit more definition on comparing loads and predicting recoil. That was part of the original question.

The second part of the question was concerning burn rate. This took a bit more understanding than I had of recoil. Having an idea of how muzzle pressure related, but not being able to isolate that from charge weight was the next step.

Sitting down with Quickload, I was able to come up with two loads that had the same predicted velocity and charge weight and enough difference in muzzle pressure that I thought could be felt at the shoulder. Roughly 600 psi., 3711 & 3095.

Using the included recoil calculator, a couple of terms I was unfamiliar with came up. Muzzle gas force and Peak force recoil.

Muzzle gas force, seemed like a reasonable predictor for comparing felt recoil.

As a refresher the load is 45-70 with a 325 grn bullet at 2000 fps. Charge weight was 40 grains of 5744 and 4100. The numbers below are predicted.

4100
peak press. 41,500
Muzzle press. 3095
Velocity 2030
Muzzle gas force 500
Peak recoil force 6706

5744
Peak press. 37232
Muzzle press. 3711
Velocity 2029
Muzzle gas force 600
Peak recoil force 6016

Since muzzle pressure and the gas force generated on bullet exit is a big factor of recoil, it makes sense that these numbers are a reasonable indicator of felt recoil.

Real world results needed to be judged by feel, which is subjective. For that I simply shot 10 rounds alternating powders. The velocity spread was 30fps, probably a but higher than actual since it was off hand. There was definitely a difference in my ability to control the rifle and felt recoil, with the edge going to the faster powder with less muzzle pressure and gas force, 4100.

Not groundbreaking I'm sure, but I learned something and wanted to thank those that gave me some things to study and directions to where I might find the answers.

 

[ireload2]

This is your problem
Quote
The load/rifle combination is a 325 grain bullet, 2000 fps, #8 rifle and charge weights in the 48-55 grain range. Recoil is basically in the 30-40 ft lbs.
End Quote

I shoot 45-70 a lot. I have more than few of them including Browning 1885 replicas. 2000 FPS is pretty dumb if recoil bothers you.
Slow your velocity down to 1100 to 1200.
I shoot 300 grain cast bullets with 13 grains of Unique in a light Ruger #3. It is like shooting a large .22 LR. I also shoot 500 grn cast bullets in a Browning 1885 BPCR. The BPCR weighs a few oz short of 12 lbs. The powder charge is 23 grains of SR-4759. Other suitable powders are 2400, 5744 and 4198.
Keep your velocity down to 1100 to 1200. Use a bullet suited to the weight of the rifle. Use a heavy rifle if possible. Mount a heavy scope on it if that is tolerable. Have fun. 2000 fps in a 45-70 is never going to be fun.

 

[ireload2]

Shot shell manufacturers play around with powders to reduce the recoil from 1200 fps loads in skeet and trap loads. You might explore how the shot shell companies reduce recoil. One other thing that is popular are the Federal paper tube shells.Skeet shooters claim the Federal paper tube hulls produce less recoil. I never paid much attention to the shot shell stuff because I loaded my own shells.

I did find after a decade of skeet shooting that my arms learned to take much of the recoil. This translated into better rifle shooting too.

 

[dellet]

This is your problem
Quote
The load/rifle combination is a 325 grain bullet, 2000 fps, #8 rifle and charge weights in the 48-55 grain range. Recoil is basically in the 30-40 ft lbs.
End Quote

I shoot 45-70 a lot. I have more than few of them including Browning 1885 replicas. 2000 FPS is pretty dumb if recoil bothers you.
Slow your velocity down to 1100 to 1200.
I shoot 300 grain cast bullets with 13 grains of Unique in a light Ruger #3. It is like shooting a large .22 LR. I also shoot 500 grn cast bullets in a Browning 1885 BPCR. The BPCR weighs a few oz short of 12 lbs. The powder charge is 23 grains of SR-4759. Other suitable powders are 2400, 5744 and 4198.
Keep your velocity down to 1100 to 1200. Use a bullet suited to the weight of the rifle. Use a heavy rifle if possible. Mount a heavy scope on it if that is tolerable. Have fun. 2000 fps in a 45-70 is never going to be fun.

I find that a certain amount of dumb and a certain amount of learning generally go hand in hand.

What I learned here will help me fine tune many different loads. Not only for the rifle in question, but for subsonic SBR’s and rimfires as well.

So in a nutshell, the recoil bothers me a lot less than the lack of knowledge I had concerning how to manipulate burn rates to control it.

 

[ireload2]

The main benefit of manipulating burn rates is to use a lot less of a faster powder to achieve modest but uniform velocities. I once shot 500 grain jacketed bullets at about 1800 fps using nearly a case full of 3031 in a 45-70 bolt gun. The recoil felt like it might break the stock. I learned a lesson and never did that again.

I find that a certain amount of dumb and a certain amount of learning generally go hand in hand.

What I learned here will help me fine tune many different loads. Not only for the rifle in question, but for subsonic SBR’s and rimfires as well.

So in a nutshell, the recoil bothers me a lot less than the lack of knowledge I had concerning how to manipulate burn rates to control it.

 

[TRA]

FWIW, it's Acceleration not Velocity. Measuring acceleration is financially prohibitive, thus the reason the industry uses velocity. That's the only way to put a layman's perspective on recoil. Btw, "Recoil" is impossible to measure with human fired firearms. Until humans are equipped with a USB port it will remain so. Recoil is perceptive and some can tell the difference and most cannot.

 

[dellet]

Recoil can be measured on a human as impact, but like your acceleration example, it is cost prohibitive and can be skewed by factors as simple as posture.

Powder charge weight, as used in certain calculators, seems to be used poorly. As in the example I posted.

If those calculations are reasonably close to correct, burn rate, or efficiency of acceleration, accounted for close to a 20% reduction in force. That’s substantial enough for many people to feel. I certainly did.

That’s why I used the term felt recoil and associated it with being able to control the rifle. Had this been done with a double or semi auto, that would have translated into faster follow up shots.

Changing to a faster powder, that will also allow a reduction in charge weight, should just make the reduction in recoil more noticeable. I simply chose to remove the charge weight from the equation and experiment only with pressure curves created from different rates of propulsion.

 

[ireload2]

Sure you can measure recoil and acceleration. Just install an accelerometer. They are common in engineering test labs.
I have even seen then used in Handloader Magazine.
Accelerometers are found on most smart phones these days.

http://www.chuckhawks.com/leupold_tour.htm

Quote
Leupold is the leader in developing the ruggedness testing that ensures a lifetime of dependable use. We spent a considerable amount of time talking with David Archerd in Quality Assurance/Product Testing. David is an interesting guy, and his lab has the most sophisticated test equipment I have ever seen. At the time of our visit they were plotting the recoil curve of a .338-378 Weatherby rifle.

Leupold test equipment is able to plot the entire recoil curve of any rifle/cartridge combination, amplitude and duration, with all the peaks. Recoil might subject a riflescope to a peak of something like 300 g acceleration, or 300 times the force of gravity. Note that duration is as important as amplitude. The longer that acceleration lasts the harder it is for the scope to endure.

They can also plot pressure curves with such precision that, according to David, they can tell when the primer ignites, when the powder starts to burn, when the bullet leaves the mouth of the case, when it engages the rifling and when it leaves the muzzle. I wish we could do this at Guns and Shooting Online.

This data can be translated into acceleration loads ("g force") over time and fed into a piece of high tech, torture test equipment about the size of a telephone booth that, in my mind, I dubbed the "Mangler." A test scope placed in this high tech scope tester can then be subjected to exactly the same loads as it would be if mounted on the rifle from which the data was collected. Any scope can be subjected to destructive loads in this machine. Naturally, Leupold also uses this technology to test other brands of scopes to see how well the competition is doing. All Leupold and most other brands and models of scopes (purchased right off the shelf in retail stores) are tested in this lab.
End quote

FWIW, it's Acceleration not Velocity. Measuring acceleration is financially prohibitive, thus the reason the industry uses velocity. That's the only way to put a layman's perspective on recoil. Btw, "Recoil" is impossible to measure with human fired firearms. Until humans are equipped with a USB port it will remain so. Recoil is perceptive and some can tell the difference and most cannot.

 

[TRA]

Sure you can measure recoil and acceleration. Just install an accelerometer. They are common in engineering test labs.
I have even seen then used in Handloader Magazine.
Accelerometers are found on most smart phones these days.

Quote
Leupold is the leader in developing the ruggedness testing that ensures a lifetime of dependable use. We spent a considerable amount of time talking with David Archerd in Quality Assurance/Product Testing. David is an interesting guy, and his lab has the most sophisticated test equipment I have ever seen. At the time of our visit they were plotting the recoil curve of a .338-378 Weatherby rifle.

Leupold test equipment is able to plot the entire recoil curve of any rifle/cartridge combination, amplitude and duration, with all the peaks. Recoil might subject a riflescope to a peak of something like 300 g acceleration, or 300 times the force of gravity. Note that duration is as important as amplitude. The longer that acceleration lasts the harder it is for the scope to endure.

They can also plot pressure curves with such precision that, according to David, they can tell when the primer ignites, when the powder starts to burn, when the bullet leaves the mouth of the case, when it engages the rifling and when it leaves the muzzle. I wish we could do this at Guns and Shooting Online.

This data can be translated into acceleration loads ("g force") over time and fed into a piece of high tech, torture test equipment about the size of a telephone booth that, in my mind, I dubbed the "Mangler." A test scope placed in this high tech scope tester can then be subjected to exactly the same loads as it would be if mounted on the rifle from which the data was collected. Any scope can be subjected to destructive loads in this machine. Naturally, Leupold also uses this technology to test other brands of scopes to see how well the competition is doing. All Leupold and most other brands and models of scopes (purchased right off the shelf in retail stores) are tested in this lab.
End quote

I should have elaborated on my statement regarding Acceleration and Velocity. Velocity is being measured at a distance of up to ~10-12 feet from the muzzle. That fps is not what is driving the recoil. Acceleration is the prime mover, creating recoil. The acceleration of the projectile and it's mass is the perpetrate data to record. The firearms reward acceleration forms the basis for the rifles kick. Although it's feasible to put a face on recoil and categorize it into different levels. The human may or not agree that this is soft and this is hard.

As has been said the real measured forces opposite the bullet travel, could be ~300g, and even a lot more. Some may cringe when they hear that the recoil they are going to be receiving will be in the 3000-5000# Lucky for us the force dies off very rapidly

The recoil calculations acquired in these labs are to qualify that their products are durable. FELT RECOIL can not be measured, as it only affects the shooter.

I'm sure Leopold has some quality lab equipment. The recoil, the actual effect from person to person to my sources has not been accomplished,

In case you misunderstood the Acceleration needed documented, is the acceleration of the projectile just as the Acceleration of the gun effects the shooter.

The shooting industry is still using F=MV. The proper calculation is F=MA

Google F=MV vs F=MA. F=MV is only measuring momentum....F=MA is measuring force, that which is necessary to produce recoil, and accelerate the gun up to speed, to cause painful recoil

I'd like to rework a rail gun or even a 338-375 rhino roller on to a electronic fixture that computer/linear motors would be used to cancel out most of the damaging harmonics, vibrations, and control the violent acceleration, and abrupt deceleration.

 

[Laurie]

Dr Geoff Kolbe (back in his Border Barrel outfit days) used an off the shelf accelerometer (car industry - from airbag triggering equipment) many years ago to build a bit of kit that worked the other way, backwards so to speak, to calculate chamber pressures.

You input bullet, rifle, and charge weight, attached the device's sensor and fired the rifle, and from that it calculated peak chamber pressure. At this distance in time, I can't remember how it allegedly did this, but it appeared to give a close approximation to actual peak pressures. The device was offered for sale, but wasn't a success IIRC - anyway it soon sank without trace. I still have Geoff's prototype somewhere.

 

[dellet]

There have been flexible sensors developed that will measure irregular surface contact points between two soft surfaces, hard and soft or hard and hard. They are used quite a bit to study impact sports. No reason that a rifle butt to the shoulder, could not be measured as easily as a kick or helmet to the ribs.

Sadly the budgeting department for this project had tight purse strings.

 

[Sheldon N]

There's an excellent description of recoil energy vs felt recoil in this article. Very readable with good visual graphs explaining the discussion:

http://precisionrifleblog.com/2015/07/01/muzzle-brakes-recoil-primer-test-equipment-rifles/

They used sensors to plot both peak force and total duration of force. Other posts in the series go on to measure muzzle brakes and suppressors across different calibers. Very interesting info.

 

[ireload2]

No you are wrong. Acceleration of the bullet is not important to the shooter except for its translation into rifle recoil.
The bullet does not directly impact the shooter. Only the recoil velocity of the rifle affects the shooter. Both the recoil velocity and acceleration of the rifle can be measured using an accelerometer. Because you can easily weigh the rifle you can also calculate the recoil energy of the rifle and its momentum.
Who cares what the mysterious felt recoil is? No 2 humans perceive recoil the same way. But any 2 humans can measure recoil of a rifle with an accelerometer.

I should have elaborated on my statement regarding Acceleration and Velocity. Velocity is being measured at a distance of up to ~10-12 feet from the muzzle. That fps is not what is driving the recoil. Acceleration is the prime mover, creating recoil. The acceleration of the projectile and it's mass is the perpetrate data to record. The firearms reward acceleration forms the basis for the rifles kick. Although it's feasible to put a face on recoil and categorize it into different levels. The human may or not agree that this is soft and this is hard.

As has been said the real measured forces opposite the bullet travel, could be ~300g, and even a lot more. Some may cringe when they hear that the recoil they are going to be receiving will be in the 3000-5000# Lucky for us the force dies off very rapidly

The recoil calculations acquired in these labs are to qualify that their products are durable. FELT RECOIL can not be measured, as it only affects the shooter.

I'm sure Leopold has some quality lab equipment. The recoil, the actual effect from person to person to my sources has not been accomplished,

In case you misunderstood the Acceleration needed documented, is the acceleration of the projectile just as the Acceleration of the gun effects the shooter.

The shooting industry is still using F=MV. The proper calculation is F=MA

Google F=MV vs F=MA. F=MV is only measuring momentum....F=MA is measuring force, that which is necessary to produce recoil, and accelerate the gun up to speed, to cause painful recoil

I'd like to rework a rail gun or even a 338-375 rhino roller on to a electronic fixture that computer/linear motors would be used to cancel out most of the damaging harmonics, vibrations, and control the violent acceleration, and abrupt deceleration.

 

[TRA]

OK. the impact of the rifle with your shoulder is the result of the the rifles velocity at the moment it strikes the shoulder. What drives that rifle velocity is the Weight of the projectile and the rate it is Accelerating. You are confusing the forces that create the momentum required and what changes it. Velocity is nothing more than a snapshot in time, where acceleration is how you measure the the characteristics of what caused the end result...Velocity.

You can go 100 miles per hour and there is no G forces present. It's how fast you achieved 0-100 mph that demonstrates the difference from one acceleration curve to the next. The amount of time the bullet spends traveling down the tube is the primary force that creates recoil, which is the result caused by the momentum of the rifle. Measuring velocity only tells you how hard the bullet would impact the target if it were to hit the target at that precise moment.

The affects of recoil on a person are caused by many things, not just the momentum of the rifle. the torque, the muzzle blast the characteristics of the gun itself, the design of the stock. These are all vectors responsible for your perception of recoils affect on your body. All of which cannot be measured, only the person firing the firearm can determine it's amount of pain. Cartridge design and powder improvements have allowed man to alter those vectors which raise or lower ones perception of the intensity of recoil.

This graph shows what would create the softest, to the harshest on the bottom.

 

[ireload2]

You are wrong. All parameters can be measured.
How you personally perceive it on your shoulder is your personal problem so to speak.
But the recoil energy, velocity, peak values and area under the curves can easily be measured with an accelerometer and stored on a storage oscilloscope.
This is nothing but time, acceleration, velocity and the resultant area under the curve.
Until you get it the acceleration of the bullet only influences the acceleration of the rifle.
The weight of the rifle influences the recoil velocity. A 100 pound rifle will recoil much differently than an 8 lb rifle with the same bullet acceleration.
Therefore the shooter does not perceive what the bullet does. The shooter only perceives what the rifle does. You could launch the rifle backward with a hydraulic cylinder and no bullet. The "shooter" would still perceive recoil.

OK. the impact of the rifle with your shoulder is the result of the the rifles velocity at the moment it strikes the shoulder. What drives that rifle velocity is the Weight of the projectile and the rate it is Accelerating. You are confusing the forces that create the momentum required and what changes it. Velocity is nothing more than a snapshot in time, where acceleration is how you measure the the characteristics of what caused the end result...Velocity.

You can go 100 miles per hour and there is no G forces present. It's how fast you achieved 0-100 mph that demonstrates the difference from one acceleration curve to the next. The amount of time the bullet spends traveling down the tube is the primary force that creates recoil, which is the result caused by the momentum of the rifle. Measuring velocity only tells you how hard the bullet would impact the target if it were to hit the target at that precise moment.

The affects of recoil on a person are caused by many things, not just the momentum of the rifle. the torque, the muzzle blast the characteristics of the gun itself, the design of the stock. These are all vectors responsible for your perception of recoils affect on your body. All of which cannot be measured, only the person firing the firearm can determine it's amount of pain. Cartridge design and powder improvements have allowed man to alter those vectors which raise or lower ones perception of the intensity of recoil.

This graph shows what would create the softest, to the harshest on the bottom.

 

[TRA]

You are wrong. All parameters can be measured.
How you personally perceive it on your shoulder is your personal problem so to speak.
But the recoil energy, velocity, peak values and area under the curves can easily be measured with an accelerometer and stored on a storage oscilloscope.
This is nothing but time, acceleration, velocity and the resultant area under the curve.
Until you get it the acceleration of the bullet only influences the acceleration of the rifle.
The weight of the rifle influences the recoil velocity. A 100 pound rifle will recoil much differently than an 8 lb rifle with the same bullet acceleration.
Therefore the shooter does not perceive what the bullet does. The shooter only perceives what the rifle does. You could launch the rifle backward with a hydraulic cylinder and no bullet. The "shooter" would still perceive recoil.

The OP questioned how to manage or alter the recoil of a rifle that is producing very similar velocity traits. That lies solely with the Acceleration of the bullet within the barrel, period. Why is that so hard for you to understand.

Question, what changes recoil sensation or your level of perception of such...................."ACCELERATION" of the projectile.

Measure all you want anywhere you want, without projectile acceleration there's no recoil. Like you said even the recoil has velocity. That's the key to the the science of recoil. Time is the most important vector in all physics. That's because Newton proved that Aristotle was in error.

People may find it hard to believe but with propellant and improvements with brass, handguns can achieve velocities comparable with rifles. Such was being discussed with the 28 Nosler topic. Some say it can't be done. They are the ones that don't understand what effect acceleration and deceleration have on firearms. The rifle brass will last longer but your velocity will be the same. By your theory all things will be equal because the measured velocity is the same. WRONG

We are as we speak traveling at a velocity somewhere between 800-1200 mph. Do you feel any effects from that velocity?

Your reference of using a hydraulic cylinder to launch a rifle will in fact be variable, dependent on the acceleration of the forces from the hydraulic cylinder. The speed and the intensity is infinitely variable.

You see this displayed at drag races where a vehicle will travel the 1000 ft quicker but at a slower terminal velocity.

 

[ireload2]

You don't comprehend energy do you?
The area under the time pressure curve is the energy that causes the rifle to recoil. That is a closed system until the bullet exits the muzzle..
According to your notion a load using using Unique to produce 1300 fps would have more recoil than the same velocity produced by 4198. I can tell you that it doesn't. Even though the Unique accelerates faster the muzzle velocity is the same.
Remember that kinetic energy is not acceleration.
KE = 1/2 mass x the velocity squared.
Notice that there is no time involved in energy so energy only cares about mass and velocity.
Acceleration is a rate of change of velocity with respect to time but energy is not dependent on time or acceleration.
You are still wrong and always will be until you figure out energy.

You are also wrong about the hydraulic cylinder since the control can be set to produce any velocity required. The shooter can be subjected to any recoil of the rifle without any projectile. If you are confused go back and review the formula for energy. The shooter does not feel acceleration of the bullet. The shooter only feels acceleration of the rifle .

The OP questioned how to manage or alter the recoil of a rifle that is producing very similar velocity traits. That lies solely with the Acceleration of the bullet within the barrel, period. Why is that so hard for you to understand.

Question, what changes recoil sensation or your level of perception of such...................."ACCELERATION" of the projectile.

Measure all you want anywhere you want, without projectile acceleration there's no recoil. Like you said even the recoil has velocity. That's the key to the the science of recoil. Time is the most important vector in all physics. That's because Newton proved that Aristotle was in error.

People may find it hard to believe but with propellant and improvements with brass, handguns can achieve velocities comparable with rifles. Such was being discussed with the 28 Nosler topic. Some say it can't be done. They are the ones that don't understand what effect acceleration and deceleration have on firearms. The rifle brass will last longer but your velocity will be the same. By your theory all things will be equal because the measured velocity is the same. WRONG

We are as we speak traveling at a velocity somewhere between 800-1200 mph. Do you feel any effects from that velocity?

Your reference of using a hydraulic cylinder to launch a rifle will in fact be variable, dependent on the acceleration of the forces from the hydraulic cylinder. The speed and the intensity is infinitely variable.

You see this displayed at drag races where a vehicle will travel the 1000 ft quicker but at a slower terminal velocity.

 

[TRA]

I may not understand your narrow views about energy.

You don't comprehend energy do you?
The area under the time pressure curve is the energy that causes the rifle to recoil. That is a closed system until the bullet exits the muzzle..
According to your notion a load using using Unique to produce 1300 fps would have more recoil than the same velocity produced by 4198. I can tell you that it doesn't. Even though the Unique accelerates faster the muzzle velocity is the same.
Remember that kinetic energy is not acceleration.
KE = 1/2 mass x the velocity squared.
Notice that there is no time involved in energy so energy only cares about mass and velocity.
Acceleration is a rate of change of velocity with respect to time but energy is not dependent on time or acceleration.
You are still wrong and always will be until you figure out energy.

I made no such claim about fast or slow powders. A bullet in a given cartridge may react totally different relative to cartridge design and powder rates, bullet jam neck tension, yada, yada, yada yet produce the same results. A 300wsm vs a 300wea or 300wm are good examples.

I think I'd stay clear of debating Quantum Mechanics is I were you.

You may claim felt recoil is irrelevant and is the shooters personal problem, but recoil tolerance for your scopes is your problem. Testing recoil to provide guidance for your scopes is one thing. Felt recoil is all that matters to the shooter.

I'm done with your ramble, you're right and I'm wrong. Are you happy now? I hope you realize that you are making a mountain out of a molehill.

When you learn how to measure felt recoil, please...PLEASE enlighten us.

I'm done with you

BTW powder may very well accelerate faster from one or the other, but that's immaterial with out plotting the bullet rate of change within the barrel. Velocity is NOT correct. If you don't like it, take it up with Newton.