Cartridge Efficiency vs Recoil

[ctw]

I could not get your www.jecustom.com - Home of the Assassin Muzzle Brake -faq;sight adviser for some unknown reason???? Well anyway I always enjoy your indepth comments. I can tell you don't comment off the cuff. ctw

 

[MajorSpittle]

I would need to see evidence to believe that the same bullet leaving the same rifle at the same speed produces different recoil because of different powder being used, because this is essentially what the OP was asking about. It just won't ever be enough of a difference to be felt by a shoot. The action causing the equal and opposite reaction is the bullet movement. Sure if there is a muzzle break or gas operated mechanism for the gas to apply force against it changes things a little, but a few extra grains of powder isn't going to hit enough air to create any amount of recoil that will be felt.

 

[Deleted member 46119]

I would need to see evidence to believe that the same bullet leaving the same rifle at the same speed produces different recoil because of different powder being used, because this is essentially what the OP was asking about. It just won't ever be enough of a difference to be felt by a shoot. The action causing the equal and opposite reaction is the bullet movement. Sure if there is a muzzle break or gas operated mechanism for the gas to apply force against it changes things a little, but a few extra grains of powder isn't going to hit enough air to create any amount of recoil that will be felt.

Some people are sensitive enough to tell a duff powder charge before the bullet hits the target at 100 yards. Never under estimate the power of the senses.

If you don't believe the opinions of the experienced, please write the test protocol and I'm sure you will get help collecting data.

 

[J E Custom]

I would need to see evidence to believe that the same bullet leaving the same rifle at the same speed produces different recoil because of different powder being used, because this is essentially what the OP was asking about. It just won't ever be enough of a difference to be felt by a shoot. The action causing the equal and opposite reaction is the bullet movement. Sure if there is a muzzle break or gas operated mechanism for the gas to apply force against it changes things a little, but a few extra grains of powder isn't going to hit enough air to create any amount of recoil that will be felt.

We have done lots of testing to develop a superior muzzle brake, and before we started we needed to understand all of the cause and effects of what recoil was.

Your question is a good one but it can and does happen so I did some more testing of two .308 loadings with the same weight rifle, the same weight bullets and the same velocity using a short mag
with 65.0 grains of powder at a velocity of 3000 ft/sec. and a 308 win mag using a 150 grain bullet, at 3000 ft/sec propelled by 70 grains of powder (5 More Grains).

Here is the comparison of the two.

Short mag = Physical recoil from bullet = 6.4 ft/lbs
300 win mag = Physical recoil from bullet = 6.4 ft/lbs (The same for both because velocity, and bullet weight plus rifle weight are the same.

Short Mag Recoil energy from gas 13.4 ft/lbs from 65.0 grains of powder.
300 Win mag Recoil energy from gas 14.8 ft/lbs from 70 grains of powder. (1.4 ft/lbs more recoil)

Total recoil for the two rifles.
Short mag = 19.9 ft/lbs
Win Mag =21.2 (1.3+ ft/lbs more recoil.

The available gas recoil and the actual recoil difference was almost the same.

I have found that the more efficient the cartridge, the less powder it needs to reach the same velocity. Changing the recoil produced by the gas, will also reduce the total recoil. Muzzle brakes can only reduce the recoil produced by the gas, the bullet weight, rifle weight and velocity are the only things that can change the Physical recoil from bullet inertia .

Understanding this is necessary to design a more efficient brake. Tuning a brake to a specific load can improve recoil even more because it can remove more of the gas recoil of a specific cartridge/load combination.

I hope this helps you understand this phenomena.

J E CUSTOM

 

[J E Custom]

I could not get your www.jecustom.com - Home of the Assassin Muzzle Brake -faq;sight adviser for some unknown reason???? Well anyway I always enjoy your indepth comments. I can tell you don't comment off the cuff. ctw

Thanks

When you log on to jecustom.com go to the FAQ section and the first topic is recoil.

J E CUSTOM

 

[MajorSpittle]

I am not sure how you are defining gas energy recoil. Certainly if you fired a blank you wouldn't see 13lbs of recoil.

I would think that the biggest factor for recoil difference would be the area of the base of the cartridge and the area of the muzzle crown/shape.

I appreciate you passing along your findings and I an not contesting there validity. I am just trying to learn and understand what is going on because It interests me and I want to pick a good cartridge for a lightweight long range build. Sorry for errors in post, sent from my crappie phone at work.

 

[J E Custom]

I am not sure how you are defining gas energy recoil. Certainly if you fired a blank you wouldn't see 13lbs of recoil.

I would think that the biggest factor for recoil difference would be the area of the base of the cartridge and the area of the muzzle crown/shape.

I appreciate you passing along your findings and I an not contesting there validity. I am just trying to learn and understand what is going on because It interests me and I want to pick a good cartridge for a lightweight long range build. Sorry for errors in post, sent from my crappie phone at work.

No problem, this is a debate and all post are welcome.

I will put it another way (I am not the best wordsmith) And may not have explained it very well.

There are two kinds of recoil produced when a firearm is fired. Bullet recoil caused by the bullet being accelerated down the barrel. (Newton's law). and the jet effect of the gas from the powder being pushed out the barrel. The first type of recoil can only be altered buy changing bullet weight, changing velocity and/or increasing or reducing the weight of the weapon. The bullet shape or crown have no effect of this type of recoil.

Gas recoil can be effected by many things. Burn rates, muzzle brakes, ETC (anything that redirects the gas and prevents it from exiting straight out of the bore). Case head diameters only change the
loading on the bolt in PSI.

Also If you fired a blank you would eliminate bullet recoil and only have gas recoil to deal with. Also most blanks have/need very little powder so this recoil would be very little.

Two examples of the different amounts of gas recoil and bullet recoil. A 150 grain load for a 308 using 44 grains of powder will have 56.3 % gas recoil and 43.7 % bullet recoil. A 223 rem using a 55 grain bullet and 25.0 Grains of powder will have 69.0% gas recoil and 31% bullet recoil, because of the bullet to powder ratio

So if you loaded the same powder charge and no bullet, the .308 recoil would be 6.7 ft/lbs instead of 11.9 with a bullet.

J E CUSTOM

 

[Wild Bill G]

I think majorspittle has missed alot of what has been said here. First of all the 2 rifles are firing bullets of the same weight. Second it is the weight of the powder charge that has changed not nescarly the type of powder. The size of the case head will make no ifference neither will the shape of the crown. Maybe JE it would help if you show him using 2 180gr bullets. The extra 30 grains of bullet weight makes a difference in recoil because it takes more energy to get it moving. It takes more energy to get a motor cycle moving than it does a mountain bike. That is when both bikes are being pushed by hand. So when the 300SM is fired with less powder less enrgy is burnt and recoil is less. The 300Win Mag uses more powder more enrgy burnt and more recoil.

 

[Wolf76]

I load for both of the mentioned calibers. The similarities are abundant. While the wsm is more efficient -ish, it doesn't match velocities of the original 300 wm. They are close, but not the same. Then you run into different gun configurations (wsm is more compact/ lighter) and load data. In the end, you won't beat the laws of physics. The shorter wsm case can't compete with heavy bullets because of the short/ wide case. The wsm uses faster burning powders and higher load pressures to compensate, but falls short. Just remember you don't get something for nothing.

 

[ENGUNEER]

Just to add a little extra fluid mechanics to this thread. The thrust (kick) on the rifle caused by firing a cartridge is due to three main factors: 1) the mass of the bullet and its exit (muzzle) velocity 2) the mass of the propellant and its exit velocity parallel to the rifle bore axis and 3) the pressure of the propellant at the exit compared to the atmospheric pressure. The propellant velocity can be much higher than the bullet velocity and can therefore have a higher thrust per unit of mass than the bullet. And, the propellant pressure can be quite high, adding significantly to the kick. The result is that the best thing you can do to reduce the kick is to install a muzzle brake, which causes the propellant gas to make a sideways turn (as compared to the bullet direction), thus negating its thrust. The other effects, such as reducing the propellant charge and using a propellant with a different pressure curve will have significantly less effect to the overall thrust on the rifle.

 

[jshepherd61]

It is all relevant with the angle of the neck, recoil is generated from the back pressure of the blast of the same magnitude pushing against a 30 degree angle or a 20 degree angle they will generate different back pressure simple physics of back pressure.

 

[ridge rider]

I've been considering a 300WM recently and have been reading about cartridge efficiency, overbore and the like. I came across something regarding powder charge weights and their relationship to recoil in short mag's vs standard length magnums. Maybe those of you who own or have shot both can enlighten me.

I read that a 300 WSM (for example) can produce near identical muzzle velocities as a 300 WM with the same bullet with say...10% less powder. But that recoil would somehow be less. It would seem to me that all things being equal (rifle weight, barrel length etc), the amount of force required to drive the same bullet to the same velocity would require the same amount of force to be exerted by the propellant and thus recoil force should be the same. Perhaps the recoil impulse, a longer push vs a sharp stab, would be different due to different burn rates required by each cartridge?

More scientific curiosity than anything. What has been your experience?

Mike

I am going to throw a cat in among the pigeons here.
My comments will be based upon MY OWN PERSONAL EXPERIENCES with a WSM cartridge against an "equivalent" magnum cartridge.
Unfortunately this experience was not with 30 cal as per this post but with 325WSM vs 338WinMag.
I hope that what I mention below may give you some clarity and guidance from my own personal experience as against what some people might think or read somewhere or what physics would indicate or what energy recoil tables might tell you.
I hope I do not to make any enemies here based upon the truth of my experiences..
I am sure you will find what I have to say will be somewhat interesting and something that was not expected.
I owned both of these rifles below and conducted tests at the same time side by side on the same day to determine various issues regarding recoil with my handloaded ammo. All ammunition was chronographed with my Magneto Speed chronograph.
One rifle was a Browning Titanium Mountain TI in 325WSM pushing a 220 grain Sierra Game King at 2790fps with 3802 ft/lbs energy. Rifle with scope weighed 7lbs 6 0zs
Second rifle was a Sauer 101 in 338WinMag pushing a 225 grain Hornady round at 2730fps with 3723 ft/lbs energy. Rifle with scope weighed 8lbs 9ozs.
Both rifles were shot from a bench rest with sandbag at the rear.
Recoil results were not as some might have expected.
The lighter rifle (lighter by some 1lb 3ozs) produced LESS felt recoil than the heavier rifle.
In other words the more efficient 325WSM produced LESS felt recoil than the 338WinMag with comparable bullet weights
I hope that this finding hasn't confused you any more but may have provided some credible information and clarity from the so called facts out there.
In the end it is up to you as to what you are guided by to determine which way to go.
Be wary of comments made by some who have never owned one or both of these cartridges in their rifles.

 

[ridge rider]

I've been considering a 300WM recently and have been reading about cartridge efficiency, overbore and the like. I came across something regarding powder charge weights and their relationship to recoil in short mag's vs standard length magnums. Maybe those of you who own or have shot both can enlighten me.

I read that a 300 WSM (for example) can produce near identical muzzle velocities as a 300 WM with the same bullet with say...10% less powder. But that recoil would somehow be less. It would seem to me that all things being equal (rifle weight, barrel length etc), the amount of force required to drive the same bullet to the same velocity would require the same amount of force to be exerted by the propellant and thus recoil force should be the same. Perhaps the recoil impulse, a longer push vs a sharp stab, would be different due to different burn rates required by each cartridge?

More scientific curiosity than anything. What has been your experience?

Mike

I am going to throw a cat in among the pigeons here.
My comments will be based upon MY OWN PERSONAL EXPERIENCES with a WSM cartridge against an "equivalent" magnum cartridge.
Unfortunately this experience was not with 30 cal as per this post but with 325WSM vs 338WinMag.
I hope that what I mention below may give you some clarity and guidance from my own personal experience as against what some people might think or read somewhere or what physics would indicate or what energy recoil tables might tell you.
I hope I do not to make any enemies here based upon the truth of my experiences..
I am sure you will find what I have to say will be somewhat interesting and something that was not expected.
I owned both of these rifles below and conducted tests at the same time side by side on the same day to determine various issues regarding recoil with my handloaded ammo. All ammunition was chronographed with my Magneto Speed chronograph.
One rifle was a Browning Titanium Mountain TI in 325WSM pushing a 220 grain Sierra Game King at 2790fps with 3802 ft/lbs energy. Rifle with scope weighed 7lbs 6 0zs
Second rifle was a Sauer 101 in 338WinMag pushing a 225 grain Hornady round at 2730fps with 3723 ft/lbs energy. Rifle with scope weighed 8lbs 9ozs.
Both rifles were shot from a bench rest with sandbag at the rear.
Recoil results were not as some might have expected.
The lighter rifle (lighter by some 1lb 3ozs) produced LESS felt recoil than the heavier rifle.
In other words the more efficient 325WSM produced LESS felt recoil than the 338WinMag with comparable bullet weights
I hope that this finding hasn't confused you any more but may have provided some credible information and clarity from the so called facts out there.
In the end it is up to you as to what you are guided by to determine which way to go.
Be wary of comments made by some who have never owned one or both of these cartridges in their rifles.

 

[J E Custom]

There are two types of recoil in every firearm. One is produced by the bullet being accelerated down the barrel, the other is recoil produced by the powder charge. If the bullet weight remains the same
and the velocity is also the same, the inertial recoil (From the bullet being accelerated down the barrel) will be the same.

If the bullet weight and the velocity are the same and less powder is used due to a more efficient case design or chamber improvement, powder recoil will be less. So if you can reduce the powder charge reducing the gas(powder)recoil and maintain the same velocity with the same bullet weight,
total recoil will be reduced.

There is one other thing in the equation and it is called recoil velocity. It is the rate that the weapon moves in the opposite direction. Recoil velocity can be effected by the weapon weight or the burn rate of the powder. (The faster it burns and delivers the pressure to move the bullet at the same velocity or the lighter the weapon the sharper the "felt recoil" will be.

Only testing on an accurate measuring device will show the real difference. perceived recoil is hard to quantify by the shooter because of the difference in recoil tolerance of different people.

There are so many things that effect recoil that makes it difficult to predict the actual recoil and the felt recoil (Recoil velocity). But to answer the posters question' Less powder, with all other things being equal = Means less recoil.

J E CUSTOM