Highest Recoil Energy Known

I have done some research about this subject, and it seems to end with murky answers somewhere up around 180Ft-Lbs recoil energy and I expect some other results to be added here which may even approach >200Ft-Lbs. At least for what can be proven or even credible based on calculation from real data that we know isn't "made up".

I believe with near certainty, it is not the 950 JDJ. My reasoning for this is because the load and ballistic data, with original rifle weight of 50lbs, put into a calculator yields <247Ft-Lbs recoil (not "277" as often listed). However, this is neglecting the fact that it has a heavy muzzle brake, thus recoil couldn't be that high.

To quote Chuckhawks.com on muzzle brakes;

"A properly designed muzzle brake can significantly reduce recoil. The actual effectiveness depends to an extent on the cartridge for which the rifle is chambered. Ahlman's claims a 50% recoil reduction when their Recoil Reducer muzzle brake is used on large magnum rifles. Mag-na-port International claims recoil reduction of up to 45% for their Mag-na-brake. Browning, whose BOSS (Ballistic Optimizing Shooting System) is both a muzzle brake and an accuracy tuning device, claims a recoil reduction of up to 30%. Weatherby, who claims that their Accubrake is the most effective on the market, claims recoil reduction of up to 53%.

In their literature, Weatherby compares the effectiveness of the Accubrake to several other makes of muzzle brake. According to Weatherby, who used a .416 Weatherby Magnum rifle for testing, the Recoil Reducer reduced recoil by 39%, the KDF Slimline reduced recoil by 40.6%, and the KDF Regular reduced recoil by 49%. These devices reduced recoil by an average of 42.86%. I find that pretty impressive."

Assuming a conservative value that the brake only reduces even 35% of recoil, it means a shouldered 950 JDJ would have ~161Ft-Lbs. It isn't shouldered, and some recoil must be friction absorbed by its resting areas. I think with even this much info, it can be argued that the 950 JDJ isn't the highest recoiling rifle.

At 13.6Lbs, the A-Square 577 T-Rex seems to be at least one of the top kickers, calculation shows it can surpass 140-150Ft-Lbs easily, and even go beyond 160Ft-lbs. However, even that specific rifle known by videos, has 3 mercury recoil-reducers in the stock. It must have less than it's highest predicted value, in that case.

This is where it gets murky. The 700 Nitro Express could potentially have >180-190Ft-Lbs if the 1000gr bullet is pushed over 2150FPS, with at least 220gr powder. It appears these rifles are often heavy. One of the values for one I found, and so used in calculation, is 18Lbs. They could be pushed harder, faster FPS, etc., but I have not seen this documented (yet) with a rifle at or less than 18Lbs.

The potential exists for heavy numbers to spiral out of this if they can be shown to credibly exist, at least from a shoulder fired gun somewhere.

Has anyone a source for something higher, that has been shoulder fired?

I'm just going to say it, that's likely an old wife's tale about the broken collar bone from a 50BMG with a muzzle brake that "fell off" (How? Spun in circles without being noticed until it unthreaded? Shot off, yet didn't notice?). First off, feel your collar bone. Do you put a rifle butt there to fire a rifle? If anyone put a recoiling firearm against their collar bone, my first thought is that they shouldn't be shooting a rifle--because that's up near your neck--a buttpad is placed far outside and lower than that on the body.

I see the Anzio 20mm in person at least once a year in Knob Creek, KY. It's huge, and the brake looks very efficient. The recoil from it would be nothing in comparison to that generated by rifles intended to be carried to stop dangerous game. The 20mm fires a 1500gr bullet about 3200FPS max from an Anzio, due to a shorter barrel than the 72" length design spec for M-61 cannons--those being capable of around 3400FPS.

I'm not going to tell anyone who has fired a 50BMG, 20x102mm, 20x138mm Lahti, etc., that the gun didn't have a great amount of recoil as compared to everyday rifles. Of course they have more recoil energy than typical rifles. However, they won't realistically make it into the "highest recoil contest" because of the already stated factors.

Factors include:

#1 Those are guns which use muzzle brakes. Muzzle brakes are most effective with high powder amounts of slow-burning powder, because slow-burning powders sustain higher pressure levels until muzzle exit of the projectile. Thus, there is not only more gas available, but it's still at fairly high pressures to push-off on redirect ports and counter a "rocket induced" recoil addition the rifle would have without one. This is probably why Weatherby used the 416 Wby Mag as the cartridge to demo their brake data. Bigger cases get bigger recoil reductions from brakes with all else being equal. 50% reduction is most likely obtained at minimum at such case sizes that fire high pressure rounds.

#2 Such rifles are ground-rifles or bench rifles. They lose additional recoil from tripods stuck into dirt, or even bipods sliding on a table. While those reductions can't be quantified easily, we know they produce further reductions in recoil.

#3 (This one can be argued that I am splitting hairs, or adding a new standard to the discussion, but I must make note of it.) Those cannon cartridge guns are often so heavy, that they certainly cannot be shouldered standing, but that's also not my main point with this one. They are so heavy, the actual speed of the recoiling firearm itself is incredibly low upon firing. Instead of a high speed object striking your shoulder, a low speed object with high weight simply pushes on your shoulder for a longer period. As such, the strike-PSI to the shoulder muscles is not as high as a light gun moving at a high speed--so they'll have a very low chance of even bruising you being such heavy guns. Your body may move further, giving appearance of high recoil, but what they have is high-momentum and low striking-PSI at the buttpad. In other words, they simply hurt less than dangerous game guns which are made to be carried on the hunt.

Think about this: a 9lb gun striking your shoulder at 38FPS, or a 35lb gun at only 19FPS, both having ~205Ft-Lbs recoil--which would your shoulder prefer when they initially impact it?

Finally, the 4 bores and 2 bores! Very interesting! Yes, they do seem to potentially have some credibility at first glance for world record recoil numbers. My intuition has just one thing on my mind I'd like to point out--for the sake of being able to get closer to good calculation data. The use of black powder--it's known to have a lower specific impulse energy than smokeless powders can generate. I suspect there is an average, maybe even somewhat arbitrary value used in recoil calculators, that generates a factor of energy added as a gas total yielded from current-day smokeless powders. Knowing what we know, BP simply doesn't produce the same kind of volumes of gases evolved when it decomposes into a gas. I'm not even sure if it is 40% as energetic as current single or double-base smokeless powders, assuming 100% charge weight is consumed before projectile muzzle exit (the rest is powder not fully adding gaseous impulse if it leaves the muzzle still having some solid % left to burn). With that in mind, I take it that rifle recoil energy calculators do not account closely in their output for BP use. Halving, or applying down to 40% the value of powder weight used as BP may yield a considerably closer number to the actual recoil they produce. 40-50% is just my guess from knowing a little about BP vs composite fueled rocket motors. It would be interesting to find the correct translative values for BP guns.


So...375Ft-Lbs probably gets knocked back a bit, though I do not contest the ability to shoulder fire 300Ft-Lbs or more of recoil. It can be done.

>600Ft-Lbs, though. I consider that really freaking hairy to imagine!

To be honest, that 2-bore looks like barely anything to handle in the video, especially with the wimp pads! Come on, that's cheating!

Good stuff guys. Good stuff. I wonder what the fastest recoiling rifle then becomes, at high energy--that could* be considered the most painful. Well, that's a whole new can of worms I'll save for another reply.

Goosey said:

Ed Hubel's 12GAFH makes 134 ft lbs. A whaling gun can make about 160 ft lbs if I assume a muzzle velocity of 200 ft/s. John Ross has a 4-bore for which I calculate 204 ft lbs. For Samuel Baker's "Baby" I get about 219.

But this 2-bore rifle at 536 ft lbs of free recoil energy using claimed figures is the top I bothered to calculate.

Click to expand...

Wow 536Ft-Lbs! Now I'm definitely wondering, can you provide more details on that gun? Such as who owns it, or some info closer to the source etc? Curious what data you used (not for the intention to call you out to say it's wrong, I just am really trying to find real-world values that people--or someone--actually shoots offhand).

I'd really like to do some research on the BP vs smokeless thing, and look at the formulas being used to come up with recoil calculation within the powder domain of the function. When I get some more time I will look into the conversion factors which may or may not occur.