Weapon recoil

[GreyWanderer]

Ok, according to Newton’s third law the force that acts on the bullets is equal and oposite to the force that acts on the gun, the recoil.

But I heard there are systems that prevent recoil. How do they work?

[herman_and_bill]

They don’t prevent the recoil, just lessen the felt effects. Muzzle-breaks work by redirecting the gasses backwards, or off to the sides. Weights in the gunstock spread out the effects of recoil over a longer period of time.

[silenus]

You don’t prevent recoil, you harness it. Recoil springs in a semiautomatic weapon use the recoil force to cycle the action, eject the spent shell, and chamber a new round. Fire a .45cal revolver, then fire a .45cal auto. You can feel the difference.

[GreyWanderer]

@herman_and_bill

They don’t prevent the recoil, just lessen the felt effects. Muzzle-breaks work by redirecting the gasses backwards, or off to the sides. Weights in the gunstock spread out the effects of recoil over a longer period of time.

Do the gasses really contribute so much to the recoil effect? I would guess the bullet would play a much larger part.

I can understand that weights can spread out the effect over a longer time, but what about automatic guns?

[herman_and_bill]

They are kind of like a rocket engine in reverse, pulling the gun away from your shoulder. They can be pretty nasty to be next to on the range too. I have a friend with a 50 BMG rifle, when he first got it he shot a few rounds and then got to wondering if the break really did do its job, he took it off and fired a round, resulted in a deep gash on his fore head and across the bridge of his nose.

[JXJohns]

On most rifles, recoil will also tend to life the barrel of the gun up. Many muzzle brakes are designed so that the ignited gasses are released in a direction to help force the barrel back down. An effective brake on a full auto rifle will allow the shooter to keep the gun more or less at point of aim even during rapid fire.

This comes at a cost however, excess noise. An AR-15 or AK-47 are not especially loud when equipped with typical flash suppressors as the escaping gasses are directed away from the shooter. When a muzzle brake is added, the gasses are typically directed upwards, which is not always problematic for the shooter, but any observers will be in extreme discomfort without adequate hearing protection.

[Ranger]

M-16’s and their varients also have recoil springs in their stocks.

[Eleusis]

Recoilless Rifle

The recoilless rifle functions somewhat like a rocket launcher in that its projectile is propelled with a rocket charge that vents at the rear of the weapon. However the difference is that the RCL is not open at the end as in a rocket launcher, and therefore avoids the “backblast” that would otherwise make rockets of this size dangerous to use. Instead the RCL uses a breech-block that vents to the front of the weapon, allowing the propellant gases to be redirected forward to balance the recoil of the projectile. Hence the launcher is “recoilless.” The venting of the gas expensive in terms of propellant, reducing the range.

Unlike a rocket launcher, which fires fin-stabilized rockets from a smooth bore, recoilless rifle rounds resemble conventional artillery shells. They generally have a rifling band preformed to engage the rifled launch tube, spin-stabilizing the projectile, hence the term “rifle.”. The “case” area of the shell is perforated to vent the propellant gases to the rear. The rocket stops burning when it leaves the tube, preventing injury to the operator.

[Spiny_Norman]

@Eleusis

Recoilless Rifle

Just to clarify: “Recoilless rifle” is a poorly chosen name in that it makes people think along the lines of an infantry rifle, which it does not resemble at all. So while it is indeed a recoilless weapon, it’s generally speaking a heavy, crew-served one - a sort of “portable artillery” - not the individual weapon most think of when they hear the term “rifle”.

And I disagree with the cite in that quite a few recoilless rifles (certainly all I’ve ever seen) actually do vent their gases backwards. The 84 mm Carl Gustav still in use and the venerable 106 mm Recoilless (shown mounted on one of my homeland’s imposing tank-killing vehicles) certainly generate backblast. Lots.

[gbrohman]

Now there is a guy that learns from the “School of Hard Knocks”!

@herman_and_bill

They are kind of like a rocket engine in reverse, pulling the gun away from your shoulder. They can be pretty nasty to be next to on the range too. I have a friend with a 50 BMG rifle, when he first got it he shot a few rounds and then got to wondering if the break really did do its job, he took it off and fired a round, resulted in a deep gash on his fore head and across the bridge of his nose.

[Una_Persson]

I’m fortunate to have an old Savage Arms .22 that can be switched from semi-automatic to “bolt-action” (manual) mode by pushing the slide pin in before firing. Even on a .22 you can feel the difference between allowing the energy to move the bolt and not. Or at least I can, but then I’m small.

[Eleusis]

[quote=Spiny Norman]
And I disagree with the cite in that…
The beauty of www.wikipedia.com is that you can submit corrections and addendums. The fight against ignorance expands beyond the walls of the SDMB.

[Daylon]

@GreyWanderer

Do the gasses really contribute so much to the recoil effect? I would guess the bullet would play a much larger part.

I can understand that weights can spread out the effect over a longer time, but what about automatic guns?

Just my experience - I shot a .50AE Desert Eagle and a .454 Casull revolver last weekend. The Casull kicked much harder than the deagle. With an automatic you have that top slide absorbing the recoil of the gases when you pull the trigger, in a revolver the recoil just goes straight back into your wrist.

Muzzle breaks / porting will definately lessen the percieved recoil of any gun, as will stronger slide springs and better grips.

In short, gasses DO contribute to recoil… think “for every action, there’s an equal and opposite reaction”… more gas pressure = more ‘push’ against your hand.

D.

[Kansas_Beekeeper]

@Una Persson

I’m fortunate to have an old Savage Arms .22 . . . .

Slight hijack. Una Persson, is that a Savage 6A? I’ve got one of those. I’ve never met anyone else who had one. Kind of an unusual design, but of all my guns it’s my favorite. My daughter and I were out this afternoon target shooting with it.

I’d never tried it before, but you are right, the recoil is different if you push the bolt in and don’t let it cycle.

[Una_Persson]

@Kansas Beekeeper

Slight hijack. Una Persson, is that a Savage 6A? I’ve got one of those. I’ve never met anyone else who had one. Kind of an unusual design, but of all my guns it’s my favorite. My daughter and I were out this afternoon target shooting with it.

I’d never tried it before, but you are right, the recoil is different if you push the bolt in and don’t let it cycle.

Well, I took a look just to be certain, and it says:

STEVENS
Savage Arms Corporation
Chicope Falls, Mass, USA
.22 Short, Long, and Long Rifle
Model 87B

It’s one of the coolest guns I’ve used. Can fire short through long rifle, in manual or semi-auto mode. It even has a special thing where when you pull the trigger and hold it firm (in semi auto mode), the bolt, after firing, stays open - allowing you to easily manual feed in another round - and then when you release the trigger, it shuts.

[viking]

@GreyWanderer

Do the gasses really contribute so much to the recoil effect? I would guess the bullet would play a much larger part.

Somewhat larger, yes, but I load 130 grain bullets in front of 55 grains of powder (7000 grains is a pound). Now, unless you’re getting all relativistic and converting mass to energy, the weight of the gases should be the same as the weight of the powder (there’s a negligable amount of soot left, and the gunpowder produces its own oxygen, as there just wouldn’t be time for oxygen to diffuse in from outside to power the combustion). So, with no recoil deflection, you’ve got 180 grains of stuff flying out the end of the barrel. If you were to deflect all the gas straight out sideways, you’d have 130 grains, or 2/3 as much, stuff flying out. If you deflect the gases out and slightly back towards the shooter, you can reduce the momentum transmitted to the gun even more.