Highest Recoil Energy Known

Last night I laid there in bed trying to somehow quantify the seemingly unquantifiable, known as "Felt Recoil". It wasn't long before some ideas spun about, I climbed out of bed, grabbed a Gatorade and sat down at the kitchen table. With paper, pen, and calculator, I started attempting to create a formula that would derive a value which utilized rifle recoiling velocity in combination with recoil energy, to paint a more realistic picture of what one must actually endure to their body upon firing.

Now, for all intents and purposes, this is not actually a felt recoil "score", if you will. I perceive the idea of "felt" recoil as somewhat infinitely variable; it's anatomy-based, perception-based, buttpad-relative in so many ways, hold-relative, and etc. I will make my own generalization that no two people will ever witness the same "felt" recoil with the same gun and same load--which I firmly do believe to be true.

My attempt then becomes to summate a total of known factors which can be held as actual true conditions (conditions not perceived but real), while leaving the rest out of the equation and up to the shooter to analyze based on their own variables between gun and shoulder.

I initially began with equations containing far too much waste material, which was unneeded, as some of the new variables resulted from existing variables that were already well-formed Newtonian truths--from the free recoil energy equation itself. It was important to note first, that muzzle energy has nothing to do with recoil.

If it's attempted to use muzzle energy in any way to generate a total recoil "score", it could be derived until ending up at a point where the calculation can become weighted by muzzle energy while essentially producing no recoil at all.

The inverse of this would be deriving a value with extreme recoil, yet no muzzle energy much at all, like 20Ft-Lbs. However, this situation can be entirely valid and true, unlike the inverse previous situation.

Here is why:
Every action has an equal and opposite reaction, as someone once said. Imagine that the action is a burst of explosive pressure within a confined space such as the middle of a tube. If a bullet of equal weight exists in each end of that tube, at equal distance from the explosion pressure epicenter, the expanding gases will yield the same force on both bullets, propelling them opposite directions with the same velocity. Thus they will have the same total energy as each other, but traveling opposite directions. Now, if the experiment is repeated, yet this time one bullet is made of a denser metal containing more mass than the other original bullet, the same explosive pressure force will need to act for a longer duration on the heavier bullet for it to reach the original speed of a bullet in the first test. However, during this event it must be kept in mind where the center of average volume would exist, while the original weight bullet accelerates away from the starting point more rapidly. As it is moving more rapidly than the other bullet, volume behind it increases more quickly. Therefore, the average volume-center moves in the direction of the lighter bullet, following it that direction until exiting the tube. Once it leaves the tube, pressure falls as confinement disappears. The heavier bullet ceases to incur any more reactive force as the gas vents, leaving it stalled at a velocity value that did not utilize the available tube length. Because of this, the heavier bullet is pushed on for a shorter time duration, and it's energy becomes less than the bullet which already left and utilized the full available tube length. The lighter bullet is said to gain energy through this simple idea. As the opposite bullet gains weight, the original bullet gains energy, so on and so forth.

Take these common sense ideas now and imagine the extreme version; one bullet weighs as much as an average rifle, while the other stays at original, fixed light weight. Put a stock on the lighter fixed-weight bullet--for imagination purposes it's a gun stock that weighs nothing and is considered the rifle itself. The "stocked" (call it a miniature rifle backwards in a tube) bullet has more energy than the actual opposing bullet; in other words, what we would normally call the projectile has less energy than the gun!

Anyways, off on a bit of a tangent there I went, but I think it's critical for some readers to understand why the rifle recoil energy isn't equal to the bullet energy, it's merely an issue of time duration under pressure. Both ARE pushed on equally, under the same opposing force, but that force is able to escape more quickly on the side with lighter "plug", thus it appears to bias energy travel also in that direction.

In conclusion to this, it summarizes why muzzle energy cannot be definitively tied to recoil energy, in any way, or the formula is then corrupt.

Traveling backwards a bit now, I attempted to chain any other variables together, in any way to produce a final "recoil severity score" that could not be fooled at any level. What I arrived at became stripped of complexity, short, and beautiful to me. That's not to say it's a flawless prediction, but through countless efforts I found it to essentially mimic what one would feel from the same rifle as recoil increases, or from the same butt pad as the load and/or rifle weight changes.

I call it, Marshall's Recoil Severity.

The formula is as follows:

(Recoiling velocity²)*(Free recoil energy in FT-LBS)/1000

Or

Vᵣ² * Eᵣ
1000 = Sᵣ (Recoil Severity)

I believe two reasons for this equation form to hold a high representative value of recoil severity. 1. The credibility of output from the original FRE equation--that being classic Newtonian derived--at least to a high degree, yields an acceptable basis of recoil formation law. 2. FRE is raised to an exponential value of a square of recoiling velocity, from which the square tumbles right out of the energy equation itself--meaning a given energy containing mass which is raised 2x in velocity yields a square representative (4x) energy, and is self-reducing or inherently checked upon by the variables needed to form the FRE value itself. With lowered FRE the end value is inversely reduced upon exponentially in calculated output by the FRE equation factors themselves, which include mass. Finally, a denominator of 1000 keeps the output more organized or easily generalized into I.E., 2 or 3 whole numbers of output using most existing rifle weight/cartridge combinations known to regularly exist.

Please feel free to critique any errors or problems you can find with this method for predicting recoil severity.

So, would you fire it from the shoulder?

What almost went through the 70Lb sandbag, and snapped the redneck rest plate off 5 wood screws was a light load in this particular gun. Actually a very light load from what it appears at this point. The rear bag was on a non-fixed piece of wood 2*12" with no catch or anchor points on the bench for it. It had every opportunity to slide backwards. Recoil was so severe, that the butt almost drove itself completely through the bag, with a towel double wrapped around butt. The gun was anchored down to a front bag so strongly that it was impossible to get another click on the ratchet strap without bending the strap lever. The strap was placed over chamber area behind heavy rear sight block so that if the rifle slid about 2", the sight block would catch the strap. Both 3/8" eye-bolts anchored into bench top became tilted inward after first firing. They had to be driven deeper for subsequent firing so their bent side compressed against wood firmly.

This "proof" test, which wasn't a proof test by any means, just a redneck "make sure it don't blow up with this loading" test, generated ~250Ft-lbs FRE @ 45.2 FPS recoil speed. This is at very low pressure without any primer flattening.

This particular shot would have a "Marshall Recoil Severity" rating of 511 on the shoulder.

Jim Watson said:

Considering that energy is 1/2 MV^2, you are going by the fourth power of recoil velocity. That seems a bit extreme.
Have you done any shooting to get a feel for felt recoil calculated that way?

Back in the late 19th, early 20th century when the ballistic pendulum was being employed, the likelihood of "gun headache" seemed correlated with recoil velocity.

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The calculation could need a revision, I had already begun to see this problem developing earlier today when I ran some lower numbers through, such as something like a 270 Win, 45-70 Gov't, and 458 Win Mag. They score very low values, at least at the point of 270 Win. Given what I have felt personally however, if I was to fire a load actually representative of say a strong 458 Lott loading in a 7.5Lb gun, and run it through that formula, for some reason my own perception seems to detect a force of impact far less than the FRE equation alone says I should when the FRE energy is the same but the weight of gun is actually 10Lbs (meaning the load is much heavier than a 7.5Lb Lott). At 240-250Ft-Lbs from <8Lb gun, it seems the force of impact is more than 2.5x the force of 100Ft-Lbs from 10Lb gun. Way more. It is however my perception telling me this, and that doesn't make it valid by any means. I need a lot more time to attempt to quantify what is going on mathematically to explain this. From watching high speed video of myself, it appears the faster moving lighter gun generates much more shock travel through tissue movement than a heavier gun with more FRE but less recoiling speed. Although, this should be obvious and I feel I'm just regurgitating common sense. I'm not arguing that the calculation is correct, though. Just that the severeness of bodily harm I feel exponentiates wildly more than FRE predicts as recoiling velocity starts to climb. Much more about the hold and position begin to effect the feel and impact as the recoil velocity rises substantially. Everything must be near perfect and proper in the hold, or the shock force will not disperse down the arm, torso, and legs, but will ram the shoulder with uneven distribution of force, and that hiccup which momentarily occurs because of it will move the shock down the wrong path entirely, towards the head. People who are getting retinal detachment and headaches are improperly distributing the recoil with their hold position. I learned this very early on; at only 95Ft-Lbs or so, I could easily hold improperly, and immediately after the shot began seeing stars flutter about, like standing up too fast does, but not as extreme as heading towards blackout. I'd call them "minor stars".

It scared me, because I knew this was G-force snap to the head causing it. Which immediately makes me think of retinal detachment. I started to study the way the body was moving in videos, and I could see corrections I could make which became obvious in video. Making those corrections, I realized I could jump higher and higher in energy levels without feeling any pain at all. A few times I held maybe a 1/4" higher or lower with the butt I thought, and felt pain. I analyzed those videos and determined it was forward lean angle change, along with slight firing arm droop. I practiced getting the same position repeated from the shots which I didn't feel hardly at all by studying screen shots as I was about to dry fire until it started to become muscle memory.

To answer your question, yes, I have practiced for some time to be able to handle high recoil well. I shot NRA 3P small bore in the late 90s for some years, 3x weekly practice with many competitions mixed in every other weekend or so, shooting camps, and finally started center-fire a bit more in high school. Caught the bench/long range bug with my first good shooter; a custom McMillan stocked Mauser action in 6.5-284 Norma. I know, a Mauser you say, but was all I could afford in HS for bench gun, even hated Mauser feeding/extraction--"whoops chambered it without box feeding it, beat on table or grab dowel rod now". It blew my mind how well it was built and shot that I even regret getting rid of it to this day. Then came the big bore bug after college, 50BMG, 338 Lapua. Then the "big big bore" bug. I seem to be around that phase now along with a lot of pistol training every other day or so. I live on a 500+ yard range mowed out to backstop mostly, can get out to 900+ just gets tougher to get there because of cat tails in between. So I walk out the door a couple hundred feet to the bench and get to shoot often because of it.

I will make a video for you guys if you want to see proof of load recoil. I can mount press on bench, then video shell loading at bench /powder on scale, followed by gun on scale, followed by round insertion, and firing through chronograph with no cut in video or round leaving scene. How much recoil do you want to see? 200, 250, 275Ft-Lbs? I haven't passed 260s yet but they are not too bad so I think I can maybe get 300Ft-Lbs if I'm feeling good in the moment about it. 300 might be where bruising starts.

Rifle has custom milled action with custom bbl but uses Savage 210 bolt and composite factory stock, stock butt pad, no extra padding anywhere or weight added--7.57Lbs. Firing 1062gr bullet out up near 1600FPS, gas seal is 25gr, 150-160 grains powder for 1525-1600FPS+. That's at chrono 40ft out. Gas seals can bite the chrono rods pretty well I found out. Took them off.

I'd call it a 12GA FH-Short. Full brass 3" cases. I just received full length cases for 50gr more powder, but I would need to drop to 880gr bullet or less to use them at this rifle weight or my shoulder would look like that sandbag probably (and throw sectional density in the trash as if that weren't enough). I really like the 1062gr bullets though they are designed very well and hardened well. At well under 1300FPS I think they penetrated further than 416 Rigby and others at the Linebaugh big-bore seminars probably 6-7 years back or so. They may have went the deepest at the seminar as I recall, wet paper+cow femurs+wet paper. 48" or something like that. Hard to remember now.

I weigh usually 172-174.

I've spoke with the guy that owns the 600NE pistol, he's about twice my size. Remember the energy won't be 600NE level because of barrel length. He told me it's not as bad as it looks it's when guys don't know how to hold it right.

If you put a stock on a 460SW pistol you'd think it kicked more than holding it in your hands. Recoil can be deceptive often enough until you learn how to disperse it, then you will laugh over it. But a giant guy with giant hands can probably always grip a pistol stronger than me.

Jim Watson said:

You are way ahead of me.
I am the guy who shoots .223 F class and .40-65 BPCR so I don't get kicked around by .308 and .45-70.

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BTW I think heavy recoil can only be tamed standing, but that's Captain obvious speaking again. Possibly kneeling, but not a conventional kneeling position, probably look pretty funny to do it right. The position required to shoot effectively prone is way off of an anatomy-matching position for high recoil. The butt needs to contact the muscle the same over its entire surface area to prevent bruising. To get this to happen, the shooting arm in fact needs to be high and outward, elbow top level with shoulder. Someone said that you need to lower your elbow. Don't do that! The extended out arm acts like a harmonic dampener. The shock will send a wave of skin flapping down to the elbow, and that absorbs recoil because it travels for a duration and away from point of location. Tucking arm in or down condenses the path for shock to travel, faster absorbed shock creates more forces of pressure locally to the area of origination. Lowering the arm also reduces the leverage effect of resistant force your arm has to stabilize and absorb or help out the shoulder impact. It helps out when it becomes on-plane with the rifle recoil.

If you guys want to know a trick to figuring out how to feel much less recoil, take a piece of foam or folded towel and the gun you feel kicks hard. Set the padding on the floor. Now put the muzzle on the floor against the padding. Bend forward and use the gun somewhat like a crutch, only put it where it should go on the shoulder. Press it against you hard, put your weight on it. Now move your firing arm in different positions. Even try moving the butt to slightly different places on the shoulder and repeat. You should be able to find places that pinch, and one place with one arm position you could rest on for a while. If you find it, note everything about where things are in that moment and try to repeat it firing. Fire until you are satisfied, then try forward lean positions. You want a forward slant, but not excessive where your chest gets ahead of forward knee--that's excessive. The gun barrel should rise well, that is dispersing energy down to the legs, but it shouldn't be rising because of lack of grip or looseness. If you video and note the barrel is staying closer to flat, you're taking a harder hit most likely in the shoulder and forward lean may be too much there.

Here is a video of rifle at 198Ft-Lbs FRE. It was played at 50% speed for 2 shots then 100%. It had become too dim for high-speed video to work.

Note the difference in hold.

His shoulder bruised, broke blood vessels in a line, mine did not.

Stevie-Ray said:

.600 Nitro pistol. This is downright crazy. I have a .45-70 T/C Contender with a tapered barrel, and shooting factory 300 grain Rems or Wins are downright painful. Feels like a firecracker going off in your hand every time. (And yes, I've had that happen for comparison)

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I'm going to have to figure out what pistol forum I was on speaking with the owner of 600NE pistol, there were a lot of exotic TC Contenders and bolt action pistols on the forum IIRC. Email search will probably locate it from years back. That guy in the video is not the guy I spoke to. He either bought it 2nd hand or had it built and there are multiples out there.

He sent me two or three videos of him firing it, 900gr @ 1650FPS or something similar to that. Big muzzle brake. He told me he always wore leather gloves to fire it so it can't slip--that's what I do with big game guns and the gloves do help. I remember the videos he sent me, and he made 600NE pistol look like nothing! The muzzle rise was only about 20-25° when he shot it. He held firmly at the forward grip and rear, really proved it could be handled when done properly. I wanted one because of him!

I don't know why the guy in video started running backwards after the shot. I think he was adding just a touch of video drama.

Capstick1 said:

Heavy recoiling guns can be difficult to master. You should take this into consideration when you're trying to decide on a DGR. Accuracy is more important than muzzle energy. If you have a pissed off African Cape Buffalo charging at you you'd better be able to hit him with that first shot. If you're using a heavy recoiling gun and having flinching issues you may not have time to get off a second shot if you miss with the first one. When I bought my first DGR 15 years ago I could have bought a Weatherby Mark V in 460 WM. This gun produces 102 ft pds of recoil energy and is unmanageable for most people. I instead chose a Ruger M77 African in 416 Rigby with about 60-70 ft pds of recoil energy. Recoil is still hard but with a little practice it's much easier to focus on hitting your target instead of thinking about getting hit by Mike Tyson like you would on the mighty 460 WM. Some people might even find the 416 Rigby recoil too much and instead choose a 375 H&H. When it comes to dangerous game though you should always use a rifle you can confidently hit your target on the first shot.

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I agree fully that the hit against deadly opponent is in great favor of your life when it's made properly first against that opponent!

Upon reaching that stage--first shot being fired--I draw some of my own conclusions on the outcomes that shot could yield; the opponent's death, or merely a time reduction to your own death.

At some point in the DG scale you do need high energy, but also a high projectile momentum and design to promote non-deflection of projectile's intended path.

Data on some of the toughest dangerous game calls for wound channel depths exceptionally long. To achieve this, you need very heavy stout bullet, with proper meplate design to balance nose-torque effects from bone collision--but still able to achieve penetration depths needed.

High sectional density actually has been known to--in rare but notable instances--work against the charged hunter when they used longer/faster projectiles instead of slower and heavier projectiles at higher weight and diameter. One of the instances I recall was a round having far excess energy than required to defeat the thickest part of elephant skull. However it didn't, bounced off head most likely due to bullet length. With lengthy bullet designs, they streamline air well, but are leveraged off-course more easily by sufficient disturbances.

The problem with bullets is that, opposite of rockets, the center of aerodynamic pressure (CP) is ahead of the center of gravity. Any frontal drag on the bullet (air/flesh/bone) continuously wants to compress CP back towards CG. One force must eventually give to the other force. The CP buildup tilts off axis until CG energy pushes the rear ahead of CP, and a wild tumble can begin without much bias to either. Centrifugal force is the only force acting as a gyro keeping the bullet from veering. (Hence at long distances, the bullet path arcs, but the bullet axis of initial aim does not--striking eventually with the belly of nose instead of nose.) So as long as the spin is staying high, bullet has a tough battle leveraging out of that spin or imposed axis of travel. As soon as impact occurs with something though, some spin is lost and so is straight-line stability. Naturally this occurs more greatly in longer bullets requiring more stabilizing spin. If the stability from spin forces is then exceeded by a leveraging from the nose (veering off a bone), the energy "snap" that occurs is a more violent transition the longer the bullet.

There was a study done in PA about why shotgun slug hunting was permitted and not rifle hunting, since the claim was laid that ricochets were most likely to carry far away with rifle bullets. The study found the inverse to be true. After deflecting, the slugs carried much greater downrange energy than the rifle bullets of similar muzzle energy and superior BC. This was because when the longer rifle bullets deflected, they released a large amount of their energy during the deflection phase because of the CP leveraging described previously, and deflected at higher angles. The rifle bullets also had very large cross sectional area gains while tumbling through air afterwards. It was then shown that the shotgun slugs deflected with more energy preservation into the ricochet transfer, deflecting at lower angles. Finally, due to their shorter length, their cross-sectional area wasn't all that much greater in a tumble than when straight! The entire ricochet philosophy was debunked; it was the shotgun slug which did what the rifle bullet was accused of doing--being a greater threat from ricochet.

There's some assurance knowing the bullet is going to go down the path chosen, both in the air and in the dangerous game especially. You might even consider it an extension of accuracy.

mshootnit said:

what amazes me is the form of some guys who just handle those rifles like a boss, then other guys look good but their form is bad somehow, they get knocked off the ball.
I am pretty good at handling 17 HMR out of a heavy varmint rig offhand. Pretty mean stuff.

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Without a lead sled for that HMR? Get out!

Would any of you be interested in learning how to handle the recoil, as you say, "like a boss"? I'd be willing to try and guide with videos instead of my unending paragraphs no one probably finishes reading. I try to be much more on-point in a video.