This cartridge vs that one aurguments lately always seem to contain this statement, and I don't get it.

Please explain how it's possible to have two cartridges that are loaded to equal pressure, equal projectile weight, yet one is supposed to get higher velocity with less powder and less recoil.

Physics I understand would be that in order to propel a projectile at a higher velocity it would need more pressure exerted on it. More pressure should have an equal and opposite effect, meaning more recoil. To do this it should need more propellant if they are using equal propellant burn rates. Nate

quote:

Originally posted by BigNate:
This cartridge vs that one aurguments lately always seem to contain this statement, and I don't get it.

Please explain how it's possible to have two cartridges that are loaded to equal pressure, equal projectile weight, yet one is supposed to get higher velocity with less powder and less recoil.

Physics I understand would be that in order to propel a projectile at a higher velocity it would need more pressure exerted on it. More pressure should have an equal and opposite effect, meaning more recoil. To do this it should need more propellant if they are using equal propellant burn rates. Nate

Imagine a graph where time is plotted on the x axis and pressure ( which will be directly proportional to the force exerted on the base of the bullet) on the y axis.

From your high school physics you'll remember that the amount of work done on something, or in this case the amount of velocity the rifle bullet produces, is directly proportional to the force applied to that projectile and the time over which that force is exerted.

It is therefore the area under the graph, being a product of force and the time over which it applied, that determines the speed imparted to a given projectile and not the peak chamber pressure.

This is why progressive burning powders can sometime produce more velocity than standard powders having about the same burn rate.

A further factor seems to be that burn rate is a function of combustion pressure and the same powder will behave differently in two different calibres.


I have a 308 that produces about the same velocity as my 30.06 with standard loads, albeit with a barrel 2" longer.

If I load optimum powders for each however, (RL15 for the 308 and RL17 for the 30.06) The 30.06 comfortably eases ahead with heavier bullets.

A rifle kicks for two separate reasons. Firstly with the bullet accelerating from rest to muzzle velocity and secondly when it uncorks from the muzzle and gas vents forwards. The first allows the rifle to move rearwards about 3 millimetres. The second causes the rifle to try to fly backwards because it has become a rocket engine. The second dwarfs the first in perceived recoil because your shoulder is next in line behind the rocket.

The second is governed largely by the residual muzzle pressure and fast burning powder usually results in reduced muzzle pressure, compared to slower powder. Muzzle pressure is also why recoil brakes work.

More speed can also be gained in more ways than one. Exerting more pressure on the bullet is one way. The bullet having less resistance to accelerating would be another.

Gerard's explanation does a good job of explaining. A lot of the recoil is due to the gas exiting at 6000 to 8000 fps after the bullet leaves. The time/pressure curve is what governs it while the bullet is accelerated down the barrel, but not after it exits. The violent expansion/acceleration of the gas afterward is responsible for a lot of it. This is the reason cartridges at higher pressure/lower charge rates kick much less than overbore cartridges at lower pressure. The 416 Taylor vs 416 Rigby is a classic example. The much higher weight of powder yields much higher recoil. The contribution from the bullet is the same in both cases.

Think of it as two recoils, one due to bullet weight and velocity and one due to essentially powder weight. Research has shown that the powder jet velocity doesn't vary that much.

I don't have it here, but there was an article early last year, I believe, in American Rifleman, that concerned the development by Marlin of one of their rifles, and it addressed this issue in detail and had a lot of data. It was very revealing, and should be read by anyone contemplating a very large case at low pressure.

What determines burn rate of poweder "in a cartrdige" is the shape of the cartride, the caliber or bore size, the weight of the bullet, and the amount of friction the bullet provides. That's why you can't always go by a burn rate chart which is a test by powder manufacturers and is entirely different then how it burns inside a cartridge.

Recoil is determined from the powder gases forcing both the weight of the powder charge and weight of the bullet out.

BigNate: You've gotten some answers that may not necessarily be addressing your question, and are also partially from the School of Physics Phantasy.

If perhaps you would cite an example of two cartridges/loads that illustrate the meat of your question then maybe the answers would be more concise.

quote:

from the School of Physics Phantasy.

quote:

Originally posted by Ghubert:

quote:

Originally posted by BigNate:
[b]Please explain how it's possible to have two cartridges that are loaded to equal pressure, equal projectile weight, yet one is supposed to get higher velocity with less powder and less recoil.

Imagine a graph where time is plotted on the x axis and pressure ( which will be directly proportional to the force exerted on the base of the bullet) on the y axis.

From your high school physics you'll remember that the amount of work done on something, or in this case the amount of velocity the rifle bullet produces, is directly proportional to the force applied to that projectile and the time over which that force is exerted.

It is therefore the area under the graph, being a product of force and the time over which it applied.

.

This quote above is both the why and how.

Look at it this way...

If one powder burns at X safe maximum pressure, for Y time, it will impart a certain velocity to a 150 grain bullet of particular diameter (base area, actually).

If another powder is burning at a slower rate of speed it can either burn at a lower pressure, which may reduce the bullet speed if the same amount of powder is used, OR

it can burn until the same pressure is reached, and by using more powder, extend the time of burn to maybe 1.2 Y, and produce a higher velocity.

Whether that produces more recoil or less depends on the operating pressure of each cartridge AND the fact that both any unburned powder and any produced gas both have mass which are being pushed down the bore as well as the bullet. That powder and gas in effect increases the weight of projectum fired and may increase or decrease felt recoil. If recoil velocity is slowed, the amount apllied to the shooter's body is less at any given moment, even if in total it may actually be more.

The muzzle pressure's "rocket" effect also comes into play as was explained ealier by Ghubert IIRC.

Most recently the aurgument of .30-06 vs the 8x57 I believe it was. The example was both shooting 200gr bullets.

I understand how recoil is generated. I understand changes in powders will effect velocity.

If both are using equal weight bullets, equal pressure, equal length barrels, and the same propellant, the only only variable is the surface area behind the bullet matched to case volume.

If one were to machine a banded solid (less friction) with a dished based (increased surface area) the bullet would be abaout as effeciant as possible. Though as long as the bullets are the same weight the diameter of the base is the actual variable. This only leaves case geometry and charge weight.

If you can impart the same pressure over a larger surface area the imparted force will be greater. If case capacity is larger I would think being able to provide that pressure for a longer period of time would yield higher performance. Yet the aurgument seems to be that the smaller case with less powder will equal the performance (338-06 vs 338WM) or exceed it. (8x57 vs .30-06)

It seems clear to me that an overbore case vs straight walled will have more felt recoil due to the thrust over a longer time frame, where the straight case sees a much quicker drop in pressure so the velocity of the recoil drops quickly. These two are entirely different in performance though. One launches a larger bullet usually slower velocity, but of a heavier weight for a short distance, while the other is a longer range higher velocity. it's apples and oganges.

But in the case of the .338-06 and .338 WM they are the same caliber, same purpose. With equal weight bullets and equal length barrels, proponets of the .338-06 swear to being able to produce equal velocities with less recoil. How is this possible?

I could see equal velocities playing with different powders and charges but can't imagine the recoil being less while doing it.

Of course on the internet you can find data to support any aurgument if you look long enough. I have learned that the .338-06 will outperform the .338WM with bullets up to 225grs and equal it with 250's. Whatever, I'm not throwing out my rifles and buying all new ones, it's just that I don't get how this works and it comes up in every aurgument.

Personally, I like getting the job done with my inferior equipment. Nate

Equal velo with equal length barrels between the 338-06 and 338 WM...Hummmm...I don't buy into that, there is a 15 gr case capacity difference between the two. Even if you load the two to identical pressures the 338WM will come out ahead.

I have a long throated 26" bbl 338-06 that will do 2720 fs with a 225 gr Horn SP, IMR4320 and Varget powders but requires more powder because of the throating amoung other things. It has been doing that velo(at sea level) with that bullet and load since it was built in the early 69's That is just about what SOME FACTORY numbers are for the 338 WM...or were last time I looked at factory numbers, quite a while back...but I guarantee you I can go WELL beyound that velo with handloads in the 338 WM and the additional powder space...ACTUAL chronoed numbers not some wistfull thinking.

There is a whole lot of HOT AIR being blown about on the internet...you have to remember people say the darndest things and compare apples to cumquates, believe in ghosts and goblins, have to prove a point, get drunk and do bad things. HOW can you take anything said on forums as gospel...I've been at this game a long time and have learned tricks the hard way that a whole lot of people have never heard of on how to increase the velo for a specific cartridge...apply those same tricks to the 338 WM and watch the 338-06 eat its dust.

That's not dissing the 338-06...I like mine fine and it does the job on any animal I ever pointed at, but the 338WM has a ~15 gr larger case capacity, that's about 18% greater usefulness...anything you can do to increase the velo in the '06 case can be done in the WM case and when you run out of steam in the '06, you still have 18% more to go in the WM case.

The recoil difference is in the AMOUNT of powder difference being used, keeping the same bullet weight, barrel length, and pressure...less powder of a slightly different burn rate translates into less recoil...simple physics. Check out the latest Sierra and Hornady manuals...all the data is there to read...forget the krap coming out of the ether.

The 338-06 with a 225 gr Hornady bullet and a 23.5" bbl uses ~53-55 gr of 4 different powders to attain 2700fs...the 338WM with the same bullet in a 24" bbl uses ~69-73 grs of 6 different powders to attain 2800fs...that's a good 20 gr difference. 17-20 extra gr of powder translates into an additional amount of recoil...not much due to the powder weight but you have to add in the gas jet the extra powder generates...YOU can go online to a recoil calculator to find out how much.

The Sierra Manual uses a 21.5" bbl in the 338WM, 215gr bullets and between 71 and 76 gr of 2 different powders to achieve 2900fs. The 338-06 with a 25" bbl and 55-66 gr of 3 different powders hits 2700fs.

John Barsness has written many excellent articles on this sport...including a very good one on how to calculate the differences between two bullet weights, two different case, two calibers and the increase in velo by "Ackleyizing" a case...Check out Handloader #187, page 24, "Case Capacity and Velocity - Do the simple math." it might help.

Different barrel lengths, different rifles, different powders, different times and places, different reloading and shooting conditions, different...different...different.

ALL these differences have to be taken into consideration and understood as to how each affect the outcome.

If you don't fully understand all the excellent information that was posted in this link, don't feel bad...many others don't. Ghubert and Gerard did give good answers, but the subject of ballistics is full of physics, math, and things most people don't even begin to understand, so trying to explain is an exercise in futility, not to mention the considerable amount of BS that gets spread around by the peanut gallery, and the totally wrong answers that creep in there also.

Now I threw in my pennies and confused the issue even more. What can I say? NOTHING in this sport is black and white and you can't believe ANYONE...for all the obvious reasons.

Suffice to say, if you want to get deep into ballistics, you need a good chrono, a couple of software programs so you can crunch the numbers, and a bunch of different caliber rifle to provide you with data.

Luck.

Generally speaking, I agree with you Nate.

There ARE specific cartridge comparisons which, with just the right combo of bullet, barrel length, and load may do the trick of more velocity with less powder and recoil, but that certainly is not true across the spectrum of loads in those cartridges.

Matter of fact, where it does happen, it is usually an extreme example of "cherry picking" both cartridge comparisons and data, in my opinion.

And I'm with you on the .338 Mag vs. .338-'06 data. I've shot many various enlargments of the old '06 clear back to the very early 1960s, and I simply disregard those claims as wishful thinking.

They are all good cartridges, my own favourite being the 8mm/06 AI. But even it ain't gonna commonly run with the bigger cartridges of the same bore. To believe otherwise is to deny the laws of physics.

Now I suppose we'll get a ream of carefully selected data proving it not only is possible but happens all the time. Ya sure, you betcha, Sven. In your Vodka dreams. Certain selected loads, MAYBE. Across the board, no way Jose.

I put that claim right in there with the one about illegal aliens contributing more to our country than they get from it. Maybe one out of a thousand, but that's no reason to blindly idolize them or credit them with superpowers they don't possess.......

Thanks guys for the input. I'm probably a poor student but the deeper I dig the cloudier the puddle! Nate

Two recoil events are generated when a rifle is fired.

The bullet unplugging from the muzzle and gas venting forwards, remains by far the greatest factor.

Example 1:

Place a rifle in a fixture that is free to slide to the rear when the rifle is fired.
Fire the rifle with a given load and measure how far it moves.
Fit a recoil brake to the rifle, thereby increasing the weight of the rifle by 2%.
Fire it again with the same load.
Recoil reduces by much more than 2%. More like 40% to 50%.

Same bullet, same pressure, same muzzle velocity. What has changed? The gas escaping from the muzzle no longer vents straight to the front.

Example 2:

Place a rifle in a fixture that is free to slide to the rear when the rifle is fired.
Fire the rifle with a 200gr bullet and measure how far it moves.
Fire the rifle with a 100gr bullet at the same pressure level and measure how far it moves.
This reduces the bullet and powder weight by about 40%.

I will put money on it that it will not even be close to 40% or 50%. More like 20%

The weight of the bullet and powder is not worth fretting over, other than choosing components that will reduce muzzle pressure as much as is practical.

I believe there is more to it. Recoil will depend on the weight of the rifle (let us assume good stock design in all cases), bullet weight and velocity, plus the residual pressure of the gas at bullet exit, plus the diameter of the bore, plus the weight of powder and the volume of the barrel and chamber. It would be a very complex high order differential equation that would determine the total recoil considering al these factors. However it is clear that a 50 caliber rifle shooting a 500 grain bullet with a given exit pressure and velocity will recoil more than a 45 caliber rifle firing the same weight bullet at the same exit pressure and velocity, because the gas has more area of atmosphere to operate on to produce the recoil. Force = pressure times area. However a 45 caliber rifle could not propell a 500 grain bullet at the same velocity as a 50 caliber rifle with the same pressure curve as it has less area of bullet to operate on. So it must operate at higher pressure overall. (not necessarily exit pressure). Therin lies the complication. I am sure the 505 Gibbs can drive a 500gn bullet at 2600fps. (I have taken mine to 2500fps with the 525gn bullet, and it is still mild pressure), but I am sure that you will get more recoil out of that than out of the 460 Weatherby driving a 500 gn bullet at 2600fps. For two reasons. 1.) you need more powder in the Gibbs. 2.) you have a bigger bore, so there is more area for the gas pressure to act on. I don't believe you can ever really compare apples with apples in this argument. Big bores recoil more than small bores. Magnum calibers recoil more than non magnums (of the same bore diameter), and heavy projectiles recoil more than light ones, (when driven as fast as they can be in a given caliber). That is all you really need to know.

Gentlemen:

Gerard is 100% correct. It's simple physics and it's the same principles used when big guns are designed.

quote:

Originally posted by Alberta Canuck:


The muzzle pressure's "rocket" effect also comes into play as was explained ealier by Ghubert IIRC.

I wish AC, I took the question to be one of velocity and went off on one.

Gerrard of course did a superlative job of explaining recoil and it's contribution to recoil.

As a side note I've looked into it from first principles and off course it makes perfect sense.

To check my understanding of the matter, I hope Gerrard or one of the other knowledgeable blokes will put me right if I've got this wrong, I'll just go into the mechanics of it for a moment.

Recoil arises as a result of Newtons third law which stated simply is that for every action there is an equal and opposite reaction.

Therefore whatever the total energy of all ejecta from the rifle, ie the bullet and the combustion products will be equal to the total recoil energy of the rifle itself, minus small losses for noise, light, heat etc.

Kinetic energy is equal half of the mass of an object multiplied by the square of it's velocity.

This is where what Gerrard is talking about becomes clear, taking the example a 30.06 loaded with a 10 gram (156 grain) bullet at 880 M/s (2900fps) loaded with 4 grammes (62 grains) of powder.

The kinetic energy of the bullet is 1/2mv2 = ~3870 joules.


The KE of the powder ejecta ( gasses and unburnt powder ) is calculated from a velocity of ( From my researches) around1830 M/s ( about 6000fps ) and a mass of 4 grammes ( or 62 grains).

1/2mv2 gives a kinetic energy to the ejecta of almost 6700 joules.

It can be seen then that the effect of the bullet on total recoil energy, ignoring losses for a moment, is almost half of the powder ejecta component.

I'm not sure about the nozzle effect of the muzzle as mentioned above, from what I do know about rocket motor design a venturi of some sort is vital to producing usable thrust and I'm not at all sure how it would work from a straight tube. I need to do some more research I think.

quote:

Equal velo with equal length barrels between the 338-06 and 338 WM...Hummmm

A person can claim anything they want. As to saying equal pressure how many have pressure equipment.

I have a larger version of the 338-06 called a 340PDK. Think a Rocky Gibbs type case plus a little. The 340PDK had a 24" I had a 338Wmag with a 22". My handloads in my 340 had no trouble beating factory 338wmags for 225gr and less. 250s and the 338 pulled away. Now comparing handloads to handloads light bullets my 340 could basically equal my 338 but used 2" more barrel to do it.

Did the same comparison for a 280PDK and 7mag. Basically same results.

I've done a lot of comparison and testing in the last 40 years. What I found is capacity will win unless you are SUPER OVERBORE. Maybe not by much but it will win. With lighter bullets can a smaller case beloaded to equal larger facotry sure. Handload to handload cpacity wins. Will that last few fps cost you in required powder and recoil? Darn right it will.

As I tried to say above, this whole issue centers around, basically, how much powder it takes to reach a given muzzle velocity. You can theorize to your heart's content about pressure curves etc, but they relate to efficiency and instantaneous values. The free recoil (not felt recoil) of a rifle depends on only five things. Rifle weight, bullet weight, powder weight, bullet exit velocity, and gas exit velocity. Nothing else has any impact on free recoil. Nothing. Barrel bore area, cartridge base area, case shape and volume, bore drag etc, etc, etc, only enter into how you end up with one of the last two values listed.

Look at a 416 Rigby and a 416 Taylor. Both in 10 pound guns. Both with 400 grain bullets. Both with 2300 fps bullet velocities (to avoid that 2400 argument). The Taylor will do this with about 71 gr of Rl-15. The Rigby requires about 98 gr of RL-22 to do the same thing, due to the larger case. Yes the Rigby has more potential, but you pay for that by having to use 38% more powder. How does that effect recoil? The recoil attributed to the bullet is constant (400 grains at 2300). The energy from the powder is 38% higher for the Rigby than the Taylor. With the Taylor, the powder charge accounts for 32% of the total recoil. With the Rigby, the powder charge accounts for 39% of the recoil. In the same weight rifle, the Rigby recoils with 12% more free energy than the Taylor. This is why one of the advantages most people who use a Taylor quote, that they can use a rifle that weighs 1-2 pounds less.

The same holds true for a 30-06 vs a 300 Weatherby. A165 gr bullet in the 06 requires about 56 gr of powder to get 2900 fps. The 300 WM requires about 75 gr for the same velocity. The 30-378 would require 90-100 grains to do this as a reduced load. Which would you think kicked harder, stiff 30-06 loads or reduced loads in the 30-378? The truh is that firing reduced practice loads in the 30-378 would kick about 50% harder than full house 06 loads. Everything has a price.

These discussions seem to always go down the road of everybody's opinion of how you arrive at the numbers, but the truth is that the 5 variables listed above are all that affect free recoil. They are the only values that appear in the free recoil equation. The other issues pertain to recoil velocity, felt recoil, and internal ballistics, but have no direct bearing on recoil energy.

I cannot improve upon the excellent physics explained already which helps one to understand some of the seemingly contradictory issues.
I first noticed the "less recoil and powder but same velocity" issue when I built a lightweight .284 around a Mex Mauser. At the time I also had a Ruger 77 in .280, so there existed in hand the means to test perceived differences readily.
From the very first shots my first impressions of my .284 was surprise at how mild the recoil felt. I had also had another very light 7X57 built on a Mex Mauser which weighed scoped 7.3#s and had used it quite a bit. The .284 seemed to have even less felt recoil then the 7X57, which I mostly used 140's at 2800 in.
The various .270's I have owned and which I usually try to push 130's to 3100 in, have more perceived recoil then the mentioned R77 .280 with 140's around 3000. The .284, even in a lighter rifle, seemed easier on the shoulder then the .280 with loads which matched in weight and velocity.
I thought this an anomaly until the first short magnums arrived on the scene. I recall both hearing and reading that the .300WSM had less felt recoil then similar loads out of the full length magnums, with explanations of why related to the wide body, short length and how it affected burning etc. The .284 could be considered the first of the short magnums with its magnum width and short case albeit not for the same reasons.
Thanks to all for the time to explain the issues involved.

The original question related to equal calibre, equal projectile, same powder and different cartridge capacities delivering the stated effects.
*everything else being equal the available case volume has the biggest effect on max pressure.
- powder choice has an effect that skews the results........you can only validly compare loads of a powder that burns equally well in both the cartridges chosen.
- choosing a powder that burns well at 100% burn in one cartridge but not the other, produces anomalous results.
This is a major cause of data that claims velocity advantages for smaller case capacities.

*you cannot compare cartridges of wildly different capacities because those cartridges use different powders to be efficient & faster powders efficient in smaller case capacities cause pressure spikes in significantly larger case capacities

Given a powder in the comparison that produces 100% burn in both of the cartridges chosen for a valid comparison & the powder is efficient in both cartridges...........it is an immutable fact that the larger case must use more powder to achieve the same max pressure. Available volume for gas expansion in the first millisecond of ignition is the principle influence on max pressure.

Similarly, the lower powder charge in the smaller cartridge, producing the same pressure results in a different pressure curve during the push down the barrel and a lower exit velocity, as the area under the pressure curve is smaller for the smaller cartridge, provided the max pressure really is the same as for the smaller cartridge.

that puts paid to the higher velocity claims for the smaller cartridge with everything else being equal .

- how equal the ASSUMED pressures really are & the basis of the claimed equal pressure seriously affects the claimed result.
- choice of cartridges for the comparison affects the result.
- choice of powder for the comparison affects the result

- All affect the available energy imparted to the projectile, its exit velocity and total ejecta energy.
- felt recoil is a different thing to free recoil...........its significantly influenced by parameters outside of the inherent energy of the cartridge & its load.

Those examples ( selectively chosen by the proponent) that claim higher velocity at lower recoil in the context of the OP question are inevitably and absolutely the result of invalid test conditions that are inherently anomalous.

quote:

Originally posted by BigNate:
This cartridge vs that one aurguments lately always seem to contain this statement, and I don't get it.

Please explain how it's possible to have two cartridges that are loaded to equal pressure, equal projectile weight, yet one is supposed to get higher velocity with less powder and less recoil.

Physics I understand would be that in order to propel a projectile at a higher velocity it would need more pressure exerted on it. More pressure should have an equal and opposite effect, meaning more recoil. To do this it should need more propellant if they are using equal propellant burn rates. Nate

You have to believe in magic.

What the hey...EVERYONE cherrypicks fer chrisakes. I do it everytime I want to OPTIMIZE and MAXIMIZE the potential of ANYONE of my rifles...WHO DOESN'T?? and if you don't you are missing out on that extra velo/energy. That DOESN'T mean jacking the loads into meltdown...it means to develop an OPTIMIZED AND MAXIMISED load for the weather and terraine conditions I expect to be hunting in, the animal I expect to shoot and the distances I expect.

And WHAT crime is it to cherrypick...except to keep the pot stirred or to whiz on someones argument.

John Barsness's simple formula for calculating velocities is 1/4 the percentage difference times the lower velo, added to the smaller cases lower velo equals a very close approximation of the actual difference in velocity seen in every reloading manual AND software program number crunching going back to Powleys cardboard slipstick calculators.

"VELOCITY INCREASES AT 1/4 THE RATE OF CASE CAPACITY" John Barsness.

The percentage difference between the 338-06 and 338 WM is about 18%...1/4 of 18% is about 4.5%...4.5% times 2700fs(roughly the velocity of the 339-06 using a 225gr bullet in a 26" bbl) = ~121.5fs added to the 2700fs = ~2821fs...go check out a reloading manual and see that is roughly the difference between the 338-06 and the 338 WM...WITHOUT CHERRYPICKING...JUST WHAT I POINTED OUT.

I run this little calculation time and time again, THEN actually test it out when I finish building that specific wildcat.

Anyone wanting to crunch some numbers can do a succession of 338, 35, 375, 416 cal cases starting from 338/375-06 and on through my next project, a blown out 338/375 Rigby, not certain which just yet...it doesn't take long with a calculator...and most of the case volume data is available online.

MOST of the examples keep saying the same thing with different words and examples.

Physics is fizziks...otherwise we would NEVER have made it to the Moon, Mars, or to the edge of OUR universe.

DenisB said it very well in his last sentence...Art S gave excellent examples with his comparisons keeping the velo constant and can be used with many other caliber/case comparisons...GHubert used the "normal" formula for calculating K.E, but Newtons second law, F=MA also comes into play also, or in this case maybe A=F/M...Gerard gave to excellent examples and the results can be calculated easily enough.

Anyone who has played around with muzzle brakes can atest to the affect of the gas component being redirected. Varmint Al has s recoil calculator that will account for the gas component being subtracted from the total recoil, and also give the recoil between the two bullet weights.

You also have to keep in mind that energy increases at the SQUARE OF THE VELOCITY, but only PROPORTIONAL TO THE BULLET WEIGHT.

NOW...if there were some way to put ALL these excellent arguments into ONE simple to understand, short, cogent treatise and put it in a sticky, then maybe it would turn on the light for all those that are lost in the dark.

One can only hope.

Luck

quote:

Originally posted by Art S.:
... Nothing else has any impact on free recoil. Nothing. Barrel bore area, cartridge base area, case shape and volume, bore drag etc, etc, etc.

If free recoil is the number representing the area under the recoil curve then perhaps that is correct. However if you have two barrels, one smaller in diameter than the other, but longer, so that the volume is the same, and both have the same residual exit pressure, they will both have the same weight of gas. However I doubt that they will have the same rocket effect, simply because the gas in the long thin barrel will take longer to discharge, and so the recoil curve will be different.
Take it a bit further a 378 Weatherby loaded with 110gn of powder behind a 300gn bullet will achieve about 2920fps (there are a number of powders that will achieve that). Similarly a 416 Rigby loaded with 110gn powder behind a 300gn bullet will achieve the same velocity, (and there are a number of powders that will achieve that). Freely available recoil programs give the same recoil numbers, but I doubt that the recoil will be the same from these two examples, given equal weight rifles and identical stock design. If anyone has acces to both calibers in rifles with the same stock design and weight who would be able to test this theory, I am sure all of us would be very interested in the result.

you are looking at a couple things "Wrong" ..
work is the area under the pressure/time curve

less powder doesn't mean less work (or even less pressure)

pressure, within a range, as an absolute, is meaningless in terms of vel

charge weight, within a range, is meaningless across powders, for work

recoil has many factors, and many ways to restate recoil, as there's not REALLY an ansi forumula

if you have a 400gr bullet, and 80 gr of powder, in a 10# gun, going 2400fps, you get X recoil, basis OLD methods of computing recoil

if you change that for 65 gr, there is 15gr less ejecta, and therefore, by formula, there is less recoil

it doesn't mention or know that we are talking h1000 vs h335 .. with likely about the same PEAK pressure (lets assume so) but the h335 comes to peak pressure sooner and keeps peak pressure longer, so the bullet comes out faster, or the same speed with less powder, and by calc, less recoil

however, it is nearly ALWAYS true that faster powders result in a FASTER recoil speed, which some people find obnoxious.

quote:

it is nearly ALWAYS true that faster powders result in a FASTER recoil speed, which some people find obnoxious.

Why is that?

As I mentioned, there was a very good article in American Rifleman that pointed out the facts of this very issue. It was about Marlin developing one of their new rifles ( I think the 450 Marlin). It appeared within the last year or two. Unfortunately, the magazine is at my other house, and NRA doesn't have an online back issue listing. If anyone has a copy, they could post the volume and issue numbers.

Gee,

I understand this example pretty simply, with the examples giving the 338/06 vs the 338 Mag, and let's add in the 340 Weatherby...

you guys seem to complicate the entire thing.. sort of like asking what time it is, and the answer given is how to build a watch...

338/06, smaller sized container, take less powder to build up your pressure...so less recoil...

same when comparing the 338 Win to the 340 WBY..

less powder to build up pressure, less recoil..

I wonder how many guys answering this question above are trained engineers... or else physics professors...

hence the detailed explanation to a simple concept...

( no intention of offending anyone,if that happened..)

So the stirring continues...

Calculating recoil has NOTHING to do with the container SIZE, i.e., case size...you're forgetting that the case is nothing but a "container inside a container"...a paper container the size of the powder charge, plus an ignition source is all that is required. The calculation parameter requirements are FIREARM WEIGHT, VELOCITY, POWDER CHARGE WEIGHT, and BULLET WEIGHT...it doesn't ask WHAT case you are thinking about.

Basically your run of the mill Momentum F(p)=MA, and Kinetic Energy formula., 1/2 mass times velocity squared formula combined...classically derivations of Newtons 2nd law. Go to Wikipedia...it's ALL there. Look at the forumulas as a basic "my dear aunt sally"...MDAS...multiply, divide, add, subtract, forget the Calculus jargon and you're home free.

You're right seafire...we need to get out to this "I'm smart" schtick and back to the REAL REALITY of everyday life and understanding.

You don't need to be a rocket scientist or even be much of a mathematician to understand...just be able to read...ALL the information on Nate's original question is found in reloading manuals and you can see it just by looking and comparing, as long as you forget about the smoke and mirrors, posturizing and total BS on the internet forums.

Or just use Barsnesses simple formula.

If you have a penchant to exersize your "little gray cells", by all means, break out the Calculus and "areas under AND over the curves" and, go to it...but don't expect many to understand or even care when you try to explain it outside an academic miliau...K.I.S.S works very well in everyday life.

Hell, I'm a fairly well educated swine, Welding Engineer wannabee, and have studied Ballistics over well over 40 year years, well before the advent of the PC and pre-pocket calculator and I'M having trouble figuring out what some posters mean and even a harder time trying to give a cogent, simple explaination without resorting to SOME mathamatical model.

Besides...say "area under the curve" and most men think about the frontal lobes or posterior, median section of some movie star, porn queen or just about every woman they see.

But all this still ISN'T answering the original posited question...I think that will require some extensive research by Nate, OUTSIDE the forums.

Luck

All I can say is that if anyone expects to understand something as complex as interior ballistics without exercising his little gray cells, tough luck.

(Ignorance may produce bliss, but it doesn't produce understanding.)

There is nothing at all wrong with operating in a state of graceful bliss...in fact that is likely one major reason a lot of us go shooting. We can enjoy a sport which, in many ways, we don't HAVE to understand well to DO well in.

But then we shouldn't expect an understanding of interior ballistics without practice and skill in using our gray cells, just like we shouldn't expect to make the national Palma team without practicing riflery A LOT!!

quote:

Originally posted by jeffeosso:
... however, it is nearly ALWAYS true that faster powders result in a FASTER recoil speed, which some people find obnoxious.

I have also heard the opposite, that slow burning powders produce more recoil. Although that could generally be because you need more powder to generate the same velocity, and so there is more weight ejected. I would still be very interested if someone could do the practical test mentioned in my previous post. I also agree with the post above where it was stated that the recoil energy is a simple 1/2 MV*V equation, and nothing else comes into it. However the V of the gas is not a simple number. It is a curve, and while it is usually simplified to a simple number you can clearly get very different "recoil" from a fast rise high peak curve and a slow rise lower peak curve that both have the same energy (area under the curve).

Agree that you cannot provide simple answers to complex issues with lots of variables.

Its the simplicity of the examples quoted by the proponents of less powder more velocity & less recoil that leads to the flawed claim based on the evidence chosen.

The proponent doesn't exercise his grey cells to realise that the simple examples he has chosen are not really equal in the basic parameters he is comparing the results from

Myths are born from fertile but misguided imaginations.

quote:

Big bores recoil more than small bores. Magnum calibers recoil more than non magnums (of the same bore diameter), and heavy projectiles recoil more than light ones, (when driven as fast as they can be in a given caliber). That is all you really need to know.

Does anyone disagree with this basic premis?

I am of the opinion that all the technical stuff is of academic interest, but in the end it doesn't really matter.

As long as you are comfortable shooting your chosen rifle, and have fun with it who really cares about the recoil?

quote:

Originally posted by 338User:
I am of the opinion that all the technical stuff is of academic interest, but in the end it doesn't really matter.

As long as you are comfortable shooting your chosen rifle, and have fun with it who really cares about the recoil?

I certainly agree with that statement.

That IS is of the nice things about rifle shooting. One doesn't really need to know why the recoil occurs to determine whether it is within one's tolerance level or not.

If it is, they can just enjoy. If it isn't, well THEN they can try to figure ot why it happens and what can be done about it. Or, they can just shoot something known to have less recoil.

Another nice thing about rifle shooting or any other shooting for that matter, is that one can get into the various aspects of it as much or as little as they like. Knowing what happens and why it happens is fun for me, so I try to learn and understand it. I also try not to take it to obsessive levels and to sort the Honey from the BS.

To each his/her own.

Relatively true general statements for the recoil situation, but you could pick your examples to try to prove the general rule does not necessarily apply.........if you were silly enough to want to do that.
The one with the most risk is the first one ( big bore bigger recoil) taken on its own & interpreted in different ways.

Its drifted away from the OP concept of the free ride where you can supposedly get higher velocity at lower recoil from a smaller cartridge in the same bore with the same .
projectile & same pressure.

the problem with sorting "the Honey from the BS" is that you typically need a little more than a basic understanding of the dynamic to be able to tell the Honey from the BS.
a lot of BS sounds logical from a limited data set.
a) you need to be able to recognise that the data set is inadequate & you need more info to be able to make a valid conclusion from the results obtained from the tests undetaken or data investigated on the subject.
&
b) to do that, you need to know more about the dynamic to recognise that you need more data to reach a valid conclusion.

The misguided imagination that creates myths is most often an imagination ,suffering from & misguided by , an omission of necessary information, to form a valid opinion.........but that doesn't stop people from doing it over & over again.

Thats human nature & the basis of his/her own.
If you are comfortable with it in your rationale & it ain't gonna kill you.......go with it.

quote:

Originally posted by 338User:

quote:

Originally posted by jeffeosso:
... however, it is nearly ALWAYS true that faster powders result in a FASTER recoil speed, which some people find obnoxious.

I have also heard the opposite, that slow burning powders produce more recoil. Although that could generally be because you need more powder to generate the same velocity,...

The legendary 340wm has a strong founded reputation for recoil that the .338win simply does not share!

Load the 340wm with slower powders for optimum case volume [to same pressure you would typically load a .338win with its faster burning optimum volume powder]...and you will get more recoil momentum from the 340wm.


The duration of the "rocket engine effect" that Gerard mentions, will be longer from the 340wm muzzle than the .338win,..simply be-cause the 340 has a larger charge of propellant- that results in a higher volume of gas that's required to escape from the same size orifice.

Loading say a 340wm to peak .338win vel. or a 338win to .33/06 peak velocities generally requires more powder than you would stuff in the smaller case....with rifles of equal weight[and equal bullet weight] means the larger case[more propellant] will produce more recoil momentum.

worst case scenario would be an optimum case vol. slow burning[not low pressure]powder load in a light weight 340wm, where because of the lighter rifle, it recoils at a higher speed than a heavier rifle,....... A heavier rifle would spread recoil over a longer time period, thus feel less severe.

However you can reduce the recoil momentum in the light weight 340wm by selecting faster burning[lower charge weight] powders.

The lighter the firearm the faster it accelerates toward the shooter. But, it has less mass and slows at a faster rate. The more mass the rifle has the slower it accelerates. That’s why heavy rifles shooting heavy bullets feel softer than light rifles with heavy bullets.

and generally speaking, a Muzzle brake[of same design] will reduce a higher % of recoil in the higher gas volume producing rounds, than the smaller ones.
e.g: a muzzle braked 7mmRem mag will show a higher percentage of recoil reduction than say a muzzle braked .280 rem.

quote:

Originally posted by 338User:

quote:

Originally posted by jeffeosso:
... however, it is nearly ALWAYS true that faster powders result in a FASTER recoil speed, which some people find obnoxious.

I have also heard the opposite, that slow burning powders produce more recoil.

please re-read my post, which may be poorly worded, as several are infering i said MORE recoil ...

i said FASTER recoil, as in FPS of the gun recoiling..

100ft of recoil is pretty tough to shoot well..

100ft is 30FP is FAR tougher to take than 100ft at 20fps....


i find slower burning powders may kick MORE, but slower, than a faster burning powder....

and, perhaps i am over thinking this.. but i prefer mercury tubes to the same weight in poured in lead for recoil reduction, as it spreads the recoil out longer, over time ...

some folks can't tell the difference.. i certainly can

quote:

Originally posted by jeffeosso:

i find slower burning powders may kick MORE, but slower, than a faster burning powder....

Jeffe,
if the higher charge weight slower powders and the lower charge weight faster powders are loaded to the same pressure,velocity of exiting gases at the muzzle, would be the same.
Hence thrust the rifle back at the same initial rate,yet the gas flow duration period from the muzzle, would be less for the faster powder lower gas volume charge,...correct?
With gas velocity being the same for both loads[at the muzzle] immediately after bullet departure, I dont see one resulting in a slower recoiling rifle than the other , just a difference duration period for gas flow.
Hence the faster powder load with its same gas vel. but lower gas volume charge, would thrust the rifle back for a shorter period of time, resulting in lower recoil momentum.

One way of putting it would be that;
- the faster powder charge results in a shorter pulse/burst?/duration of gas discharge-rifle push back,... the slower burning-higher charge weight powder would offer a longer pulse/burst period[due to higher gas volume], but not necessarily a slower gas vel. or slower rifle recoil velocity.

Barrel length is measured from the bolt face.

Therefore having a 7mm WSM @ 2.80" COAL in a 24" barel will have .6" more barrel length for the gasses to work on the bullet than a 7MM Rem Mag @ 3.40" COAL.

The shorter cartridge has effectively added .6" of barrel length W/O increasing the physical length of the barrel itself.

It can (in theory) achieve the same Mv W/a lighter powder charge W/less recoil W/a given weight bullet.

If you have a 24.6" barrel and you cut .6" off to bring it to 24", you will see about 15fps to 18fps difference, using identical ammo. No one could tell the difference that finely.

When measured from the bolt face, if two different cartridge rifles each have a 24" barrel, the barrels are 24" regardless of case length. The one will have more length of rifled section but pressure is built within the entire closed system of chamber and rifled section.

Remember what Jeffeosso said... AND RECOIL has TWO components...the actual ftlbs of energy coming back and hitting you AND the rearward SPEED of the rifle...BOTH can be changed by changing powder burn rates, which causes a change in the peak pressure AND the point/time at which that peak pressure occures and the length of time it continues...Ref TRAX.

I think this is the basis for many misunderstandings/problems when it come to "felt/subjective" recoil...and also the fact that running one or two numbers through a recoil calculator doesn't give much real data, but a TON of bogus data...plus the fact that "the speed of recoil" isn't understood by many AND the bigger the recoil number, the BADDER the gun.

Very few brag about how "LITTLE" their 14.792 cal, sumpn-sumpn from somewhere, Leroy Brown from Southie, Brontosaurous Basher, recoils...it's ALWAYS how HARD MY SHOOTER KICKS!!!

While all this is theoretically applicable, in real life it is nothing but smoke and mirrors and how much you believe in Santa Claus.

Just HOW many average hunters bother with working out all the nuances for their hunting loads...about as many as the thumbs on one hand, barely. Most just pick out a load from a manual, see how it shoots and if it keeps inside a 9" pie plate at 50 yds they go hunting and have NO trouble filling their tags.

I agree with Alberta Canuck...in many cases Bliss can be a comfort...you just "getrdone" and forget the small stuff.(or don't remember in the first place)

One thing about the Mercury recoil reducers...in the ones I have, the mercury can move back and forth a small amount which has a small effect on spreading the recoil rate over a small amount of time...the object of which is to reduce the felt recoil...AND snow the heck out of people by the advertising boys...it SOUNDS like is would work, therefore it DOES...HOW much would take a lot of testing...OBJECTIVE TESTING...leaving out the human SUBJECTIVE component.

Hey...all this conjecture and such DOES SELL SOMETHING...and MONEY makes the world go 'round.

The modern calculators that use Powley algorithms DON'T use barrel lengths per se...they use the barrel length from muzzle to boltface, the LENGTH of the cartridge case, the bullet length AND the overall loaded cartridge length and manipulate that data in an algorithm to calculate velocity...in the earlier Powley programs you had to calculate the USABLE barrel length and therefore the expansion ratio by doing some of the adding and subtracting youself and keep it within 1/4" of the distance from the muzzle to the case mouth to calculate velocity.

Much, MUCH simpler in todays programs where all those calculations are included in the algorithms PLUS all the data that has been developed over the years included into a HUGE database. I LOVE IT.

Luck