Does Muzzle Energy = Felt Recoil...?

A

Aristides

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Assume I'm looking at a handgun ballistics table for 357 magnum. A certain 110 grain bullet is listed at 1295 fps and 410 lbs muzzle energy, while another 125 grain bullet is listed at 1220 fps and 413 lbs muzzle energy. Assume the same gun is used.

Will the higher velocity of the 110 grain bullet cause more felt recoil?

Or will the higher weight of the 125 grain bullet cause more felt recoil?

Or should I assume that since the muzzle energy is about the same, these two bullets will give me about the same felt recoil?
 
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Felt recoil involves many things. Muzzle energy, recoil velocity, gun weight, bullet weight, stock design [or gun shape], how the gun fits you. Even things like muzzle flash and blast have an effect.
 
Other variables exist as well. For instance, many (most) ballistics info for .357 uses a 6" barrel. If you are shooting a 4" barrel, there will be a correction factor for bullet velocity for each weight...and this waill affet felt recoil as well.
 
Do not confuse FELT recoil with ACTUAL recoil. Actual can be calculated - there are various calculators on the web for that. Felt recoil is subjective and depends on how well your gun fits. In the case of handguns, action types and grip style and material all play a factor
 
I feel like some of you are missing the point of my question. I realize you are correct to mention these variables that will effect recoil, but remember that we are assuming the exact same gun/fit/weight/length/etc.

So, to restate my original question...

With all those "variables" being constant, I'm wondering whether I can look at a ballistics table and sort of take a "shortcut" to the recoil question by looking at the muzzle energy. Does muzzle energy at least roughly equate to felt recoil, where I can expect that a bullet with less muzzle energy will have less recoil? I.e, are muzzle energy and felt recoil closely related, assuming those other variables are constant??

Or, should I pay more attention to velocity? Would a higher velocity round likely result in more recoil, even if muzzle energy is about the same (410 and 413)?

Or will the heavier bullet mean more recoil, even though muzzle energy is the same?
 
Generally a heavier bullet will give more push. But if you launch a light bullet really fast it can generate a snappy kick. But no, you really cannot look at a table and make any kind of meaningful assumptions. There are a lot of variables here. Forget about the numbers and go shoot it.
 
Spartacus, the recoil of the heavier bullet will create more actual recoil. Newtonian physics states that for every action, there is an equal and opposite reaction. You will have 413 ft/lbs of energy in reaction to launching the 125gr bullet. The 110gr bullet will yield 410 ft/lbs of energy in reaction.

The felt recoil is dependent on the design of the gun and grip, among other things. The forward energy is contained in the tip of the bullet. The recoil, on the other hand, is spread out in the gun's frame, your hand, etc.

The entire event is not perfect. Energy is bled off in directions other than straight back or straight forward. Some is bled out through the cylinder gap, in the case of a revolver; and a certain amount of leakage into the chamber, in the case of a semi-automatic. (No chamber creates a perfect seal.) The gun attempts to rotate around its own axis, and that of the axis created by the hand gripping the gun.

I did get something from Mr. Ford's physics class at Male High School in 1964-65.
 
Recoil is proportional to the product of the mass of the ejecta (everything that comes out of the muzzle of the gun) and the velocity of the ejecta.

If you want to get a rough idea of the recoil difference between two different rounds out of the same gun you can multiply the bullet weight by the muzzle velocity. The higher the result the more recoil--all else being equal.
 
Given the scenario you presented (15 gns, 75fps and 3ft/lbs of difference), you felt or perceived recoil should be very similar. I would guess that the 125 gn load would have slightly more actual recoil. All else being equal, you'll feel the heavier bullet more.
 
The momentum of the gun is equal and opposite of the momentum of the bullet and powder gasses.

Notice that it is momentum that is equal and opposite, not energy.

Heavy, slow bullets have high momentum but low energy, they make guns kick hard.

Light, fast bullets have high energy but low momentum, they don't make guns kick as much.

If energy was what made guns kick, then a .22-250 varmint rifle would kick more than a 12 gauge shotgun.
 
The plane on which the recoil is directed also makes a difference. This comes particularly into play when comparing loadings with differing bullet weights. Generally, heavier bullets cause more muzzle climb than lighter ones do, so given two loadings with equal energy but different bullet weights and velocity, the lighter, faster bullet will direct more of it's energy straighter backwards directly into the shooter's hand while the heavier, slower bullet will direct more of it's energy upwards causing a more rotational recoil arc. This can make a difference in how the shooter percieves recoil.

Another variable is how a particular loading performs in a particular gun. For example, Federal's 357B 125grn .357 Magnum loading is listed at 1440fps for 575 ft.lbs. energy from a 4" barrel while their 357E 158grn .357 Magnum loading is listed at 1240fps for 539 ft.lbs. energy from the same length barrel. If you shoot these loadings in a shorter barrel, however, the velocities and thusly energies will be different. 125grn loadings typically run 200-250fps slower than their published velocities from a 2" barrel while 158grn loadings typically run only 100-150fps slower. So if we're shooting those Federal loadings from a 2" barrel and getting 1200fps with the 125grn bullet and 1100fps with the 158grn bullet, the heavier bullet will actually give us more energy (424 ft.lbs. as opposed to 399 ft.lbs.).
 
Others have already said it, but recoil is proportional to mass x velocity. Both factors contribute equaly to recoil- a bullet twice as heavy has the same effect on recoil as driving a bullet twice as fast.
 
Bullet Weight effects recoil much more then the velocity of the bullet.

Fixed sight revolvers are designed for a certain bullet weight. Most being 158 grins. If you use lighter bullets, the impact will be lower, if you use heavier bullets, the impact will be higher. Increasing the powder charge, thus velocity, wont affect the recoil or jump.

The barrel of a pistol and revolver are higher the the hand holding it, so when fired the gun pivots. Manufactors compensate for this by having the sighes lined up forcing the gun to shoot higher then the plain of the barrel at about 20 yards.

For this reason for my revolvers I choose the Lyman 378477 SW bullet for SD or hunting and a 148 grn WC cast bullet. Saves me from fooling with sights, or hold overs on my fix sight pistols.

It will take quite a bit space here to show the differant formula's used to prove them.

I'd recomend going to the library and checking our (or better yet ordering your own copy) of HATCHER'S NOTEBOOK MG Julian S. Hatcher. The chapter on "The Theory of Recoil.

Actually no one who is serious about shooting should be without this book.
 
I think the "weight x velocity" formula is the answer I've been looking for, with the other responses also helping me understand how to think about this question.

I did some math, comparing rounds with different "weight x velocity" assumptions, and could see that I got different relative results from when I compared just the muzzle energy numbers.

So, the answer to my question seems to be...No, one cannot use muzzle energy as a direct indicator of recoil.

But Yes, I can use use the ballistics table to give me an estimate of relative recoil between two rounds, and that estimate is "bullet weight x muzzle velocity", all other factors being equal.

Thank you, gentlemen.
 
To illustrate the difference between momentum and energy, compare a bowling ball going about 15 mph to a .22 long rifle bullet.

The bowling ball has lots of momentum but little energy.
The .22 bullet has lots of energy but little momentum.

The bowling ball will send ten bowling pins flying if it hits them just right.
The .22 bullet might tip over a pin if you hit it just right.

Bullet momentum is what makes guns kick and what makes steel silhouette targets tip over. That's why the pistol silhouette shooters like to use something like a .44 magnum and 300 grain bullets instead of a .221 Fireball shooting 50 grain bullets, even though the .221 Fireball may have just as much or more energy.
 
felt vs. free recoil

Very good review.
In actuality, as was pointed out early in this thread, actual or "free" recoil can be calculated. The best calculations involve three different formulae, not just one. One is for the free recoil impulse in lb.secs. The second is for the free recoil velocity of the firearm in fps. The third is for free recoil energy of the gun in question in ft.lbs. You need the first to do the second and the second to do the third.

The "felt recoil" question is unanswerable. This was also noted early. Everyone perceives recoil differently - based on all the variables already mentioned. Your body weight, how strong you are, the size and shape of your hands, whether you shoot one handed or two handed - all play a part in how a recoiling firearm "feels". So, to a large degree, does experience play a part. You get used to recoil.
Pete
Experiment: Take a snub nosed .38 revolver. Load it with 135 grain +p ammo. Shoot five rounds. Note the felt recoil. Take a lever action carbine rifle chambered for the round. Load the same ammo in. Shoot five rounds. The bullets will have a higher velocity and more ME but the felt recoil will be less (for most people....)
 
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Nerd Alert

Here's an equation which might cover what darkgael just said, from Appendix B of Lyman 49th:

Free Recoil Energy (ft-lbs) = (W1 * Vp + 4700 W2)(squared) / 64.348 * Wg

Where:
W1=weight of bullet in pounds. (grains divided by 7000 equals pounds)
W2=weight of powder charge in pounds.
Wg=weight of gun in pounds.
Vp=muzzle velocity of bullet in feet per second.

So, assuming I fired your bullets from my beloved GP-100, and using Unique powder loads from the same manual (which, of course, are probably not the same as yours), the 110 grain bullet would render a recoil of 31.75 ft-lbs, while the 125 grain bullet would give 36.81 ft-lbs. It doesn't sound like a big jump, but load up some 180 grain Buffalo Bore black bear stoppers, and the recoil jumps up to around a whopping 80 ft-lbs! :eek:
 
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