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Recoil reducing modifications.

Bardot

Bardot

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I see lots of posts and comments talking about modifications and tuning that reduce recoil. So can anybody tell me why the following does not apply?

Whenever a force operates in one direction there is always an equal and opposite force! (unless the laws of physics have changed since I went to school).
The end result of a firing cycle is a pellet leaving a muzzle traveling in one direction with a force of 12ft/lbs so there will be an equal and opposite force imparted to the thing that produced it. ('The recoil to the rifle'). So a rifle will recoil with a force of 12ft/lbs in the opposite direction to the barrel. So how do any gun mods REDUCE recoil ?

We can change how a gun sounds. We can change the way it feels and how it reacts when we fire it but we cannot reduce the recoil surely?
 
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Muzzle brakes and sound mods can reduce recoil as they are pushed forward (taking the rifle with it) by the expelled gasses hitting their internal surfaces.
Brakes can also redirect the expelled gas, reducing other recoil characteristics such as muzzle-flip.
With firearms there is more expelled gas travelling faster than the gas of air guns, so the effect more noticeable.
 
Sarge said:
Muzzle brakes and sound mods can reduce recoil as they are pushed forward (taking the rifle with it) by the expelled gasses hitting their internal surfaces.
Brakes can also redirect the expelled gas, reducing other recoil characteristics such as muzzle-flip.
With firearms there is more expelled gas travelling faster than the gas of air guns, so the effect more noticeable.
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Surely the same argument applies to any force pushing a muzzle brake or sound mod forwards an equal force will go the other way ! therefor no reduction in recoil. Any additional characteristics produced during the firing cycle such as muzzle flip can be counteracted by porting etc but they still do not reduce recoil.
 
The energy released by the mechanism is higher than the muzzle energy. A lot of the problems with spring recoil is that it has forward and backward motion, a sort of whiplash.
The ideal scenario would be to have equal and opposite forces canceling each other out but the real world model is more often to reduce the jolt component. A steady build up of force is much easier to account for than a fast build up, short pause a sudden reversal.

AFAIK tuning is more about not wasting energy in noise and friction, while reducing the amount of whip.
 
I think a better term is "reduced FELT recoil " , the problem being we are all different and like different things, so :for every advocate of a given tune or modification to a spring rifle, there will be as many who say the standard gun doesnt need any such modification 🤷🏼‍♂️, from experience , fitting (in my case)WW kits make for a more pleasant shooting experience with the guns I've fitted his kits to... , what I've also discovered is that I dont like the shot cycle/harshness of .177 spring rifles, regardless of the state of tune!! But that's just me!
 
Bardot said:
Surely the same argument applies to any force pushing a muzzle brake or sound mod forwards an equal force will go the other way ! therefor no reduction in recoil. Any additional characteristics produced during the firing cycle such as muzzle flip can be counteracted by porting etc but they still do not reduce recoil.
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There is a reduction. As you said: every action has an equal but opposite reaction. It is the law on the conservation of momentum.

So the bullet (or pellet) goes forward, along with a lot of very fast moving gas and other particles.
Instead of allowing all the gas to exit straight forward (which would maximize recoil), a muzzle brake has side vents or angled ports that direct the gas backward and/or sideways. This creates an opposing force that pushes the firearm forward, reducing felt recoil.

Savage Rifles, how a muzzle brake works
 
Steviewonder said:
Sounds (sorry for the pun ) interesting. Where do I find the article you mentioned ?
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They were published in Airgun World magazine a couple of years ago. I'm sure they are on the web somewhere, I did have them marked but the link is dead now. He is on here as @Nomads HFT , maybe if you ask nicely..............Shrug tt
 
The main components of recoil in a springer are the result of piston acceleration and deceleration. The movement of air mass and pellet are minor components. In a PCP the spring and hammer are minor components and the major contribution is from pellet and air mass. This explains why PCPs exhibit much less recoil than springers.

Acceleration of the piston (and most of the spring) causes a rearward force on the action. As the air pressure in front of the piston increases, the rearward force reduces, up to the point where the piston velocity peaks. What happens next is complex: the piston will start to decelerate so a forwards force is ceated by the air. Meanwhile the centre of mass of the spring is still moving forwards and, if the piston decelerates too quickly, a shock wave can be transmitted back down the spring, the piston may bounce, etc. All these effects waste energy (some dissipated in recoil) but tuning can reduce the enegy wasted.
 
Sarge said:
There is a reduction. As you said: every action has an equal but opposite reaction. It is the law on the conservation of momentum.

So the bullet (or pellet) goes forward, along with a lot of very fast moving gas and other particles.
Instead of allowing all the gas to exit straight forward (which would maximize recoil), a muzzle brake has side vents or angled ports that direct the gas backward and/or sideways. This creates an opposing force that pushes the firearm forward, reducing felt recoil.

Savage Rifles, how a muzzle brake works
Click to expand...
I have used ported firearms in the past and am aware of how gasses can help to stabilise the barrel /gun etc. I have never used a muzzle break so cannot comment on them as such but still believe that if it is being pushed forward somewhere there is a force pushing backwards. However I was originally aiming (if you pardon the pun) my comments towards air guns.
 
As others have said the majority of the recoil felt in a springer isn't the opposite force to the pellet leaving the barrel. A 10 grain pellet at 700 FPS isn't pushing back very hard on a rifle that weighs 49000 grains (7lb).
 
Cannon Fodder said:
As others have said the majority of the recoil felt in a springer isn't the opposite force to the pellet leaving the barrel. A 10 grain pellet at 700 FPS isn't pushing back very hard on a rifle that weighs 49000 grains (7lb).
Click to expand...
I'm asking why aren't the forces equal. Where is the forward force that is opposing the recoil.
 
Bardot said:
I'm asking why aren't the forces equal. Where is the forward force that is opposing the recoil.
Click to expand...
The forward force that opposes the recoil is the force acting on the piston to drive it forward.

Or in other words, the spring acts in both directions, however, because the piston has less mass than the rifle, it gets accelerated faster than the rifle.

That's why you pellet could go a few hundred yards, but your rifle will only move a few mm.
 
Sarge said:
There is a reduction. As you said: every action has an equal but opposite reaction. It is the law on the conservation of momentum.

So the bullet (or pellet) goes forward, along with a lot of very fast moving gas and other particles.
Instead of allowing all the gas to exit straight forward (which would maximize recoil), a muzzle brake has side vents or angled ports that direct the gas backward and/or sideways. This creates an opposing force that pushes the firearm forward, reducing felt recoil.

Savage Rifles, how a muzzle brake works
Click to expand...
Went away and did some reading up online. The article related to firearms rather than air guns. But reads as follows:
The rearward momentum transferred to the firearm by the primary recoil event will be equal and opposite to the momentum gain of the projectile in the forward direction (mfVf)=-(mpVp),where mf and Vf are the mass and velocity of the firearm, respectively, mp is the projectile mass, and Vp is the projectile muzzle velocity which is a function of the internal ballistics of the firearm [2]. Nothing can be done to reduce the magnitude of this momentum transfer to the firearm for a fixed projectile momentum. The situation is different for secondary recoil, however. To reduce secondary recoil, it is possible to vent the propellant gases from the barrel through ports or baffles located near the muzzle. The venting occurs after the projectile passes the ports just prior to leaving the barrel. By diverting a portion of the expanding gases through porting holes, in a direction perpendicular to the axis of the bore, the secondary recoil component is reduced. The gases can also be vented rearward reducing recoil or upward to reduce muzzle rise. This type of porting is common in both sporting shotguns and rifles.
 
Cannon Fodder said:
As others have said the majority of the recoil felt in a springer isn't the opposite force to the pellet leaving the barrel. A 10 grain pellet at 700 FPS isn't pushing back very hard on a rifle that weighs 49000 grains (7lb).
Click to expand...
The recoil does not move very much but when I put a 30g accelerometer on a rifle, the output saturated. A back of the envelope calculation gave me a 300g impulse. But its very short lived. A cheap alternative is a piezo electric microphone.
 
weepete said:
The forward force that opposes the recoil is the force acting on the piston to drive it forward.

Or in other words, the spring acts in both directions, however, because the piston has less mass than the rifle, it gets accelerated faster than the rifle.

That's why you pellet could go a few hundred yards, but your rifle will only move a few mm.
Click to expand...
Yeh I do understand the workings and science behind it ! It's why I always smile when you watch a film where some guy gets blasted by a shotgun at close range and fly's backwards. For this to happen the guy shooting the shotgun would need to fly backwards by the same amount. Forces always balance out.
 
BallisticBill said:
The main components of recoil in a springer are the result of piston acceleration and deceleration. The movement of air mass and pellet are minor components. In a PCP the spring and hammer are minor components and the major contribution is from pellet and air mass. This explains why PCPs exhibit much less recoil than springers.

Acceleration of the piston (and most of the spring) causes a rearward force on the action. As the air pressure in front of the piston increases, the rearward force reduces, up to the point where the piston velocity peaks. What happens next is complex: the piston will start to decelerate so a forwards force is ceated by the air. Meanwhile the centre of mass of the spring is still moving forwards and, if the piston decelerates too quickly, a shock wave can be transmitted back down the spring, the piston may bounce, etc. All these effects waste energy (some dissipated in recoil) but tuning can reduce the enegy wasted.
Click to expand...
So would this summery be roughly correct ? When shooting a springer the 'felt' recoil is in both forward and backwards directions. The net result of these is roughly balanced out but the actions are felt during the firing cycle. By tuning etc. the 'felt' actions of these forces is reduced and the experienced improved.
 
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