Thread: Suppressors - Am I missing something

All I know for certain is that when I used the 7mmRemMag without the suppressor, it hurts after 5 or 6 rounds, but with the suppressor I can do a whole pack of 20 and still feel fine. (Wallet hurts a fair bit but the shoulder is fine....) Yes @gadgetman you know the one.....

When all is said and done, it does not worry me how it works, all that matters is that it does.

Originally Posted by timattalon

All I know for certain is that when I used the 7mmRemMag without the suppressor, it hurts after 5 or 6 rounds, but with the suppressor I can do a whole pack of 20 and still feel fine. (Wallet hurts a fair bit but the shoulder is fine....) Yes @gadgetman you know the one.....

When all is said and done, it does not worry me how it works, all that matters is that it does.

Absolutely it works. And saves your ears at the same time.

That one you speak of is at Gunworks getting a noise sharing device added at the moment. I thought it would be good to get one and share the 'love' that we received at last years Toby shoot. Mostly I'll use it with the suppressor. Even TR loves hers with the more than sufficient muzzle brake effect of the suppressor.

Originally Posted by timattalon

And as a final note, the air thrust forward in your cartoon has been shown to actually work. Poorly but with some gain in forward momentum. Mainly due to the same aerodynamic principle that means an anemometer works. The dome shape at the front resists the air less than the shape behind it.

@timattalon,
Yes, blowing into a large sail with a big fan actually can produce a forward drive. I saw that Mythbusters episode, and it was really good they bothered to test it as the result was forward motion of the craft!!! The reason for this apparent miracle is that the sail deflected the blast of the fan sideways and rearwards. I.e. it nevertheless still illustrates an open system, not an enclosed system like a muzzle brake enclosed in a can and unable to ultimately direct blast in other directions than forwards.

Originally Posted by timattalon

Put more briefly, A muzzle brake by itself actively provides a physical forwards push to counteract the recoil. But my understanding of a suppressor is that rather that reduce the amount of energy, is slows the energy transfer to take longer reducing the time that the impact takes place. Same amount of energy transferred (or very similar) but by taking longer the speed / force of the impact is reduced.
To use the car analogy, think of a muzzle brake as an anchor attached to a chain thrown out the back that grabs the ground and applies a pull to the rear that slows the car. Where a suppressor is the act of apply a foot brake that is part of the car. (Not quite the same but I think close enough to get my point.

For all those that are telling us that suppressors cannot reduce recoil forces, please explain why most shooters find suppressed rifles are more pleasant to shoot with what certainly feels like significantly reduced recoil.......

My 7.62x54R boots like a bastard without a suppressor and leaves bruises on my (slightly built) hunting mate after a few shots, (and has flames you can almost spotlight with) but add a suppressor and he can put a couple packets through with no problems or bruising. (And I know this to be true as I have seen it and experienced the difference myself.) If suppressors do not have any effect on recoil, please explain this for us as this is very close to what the OP asked.

@timattalon,

I do not hear many say suppressors do not reduce recoil (which by definition have to mean felt recoil). The cooling and thus contraction of muzzle gases with resultant loss of pressure will reduce recoil. The slower release of gases will reduce felt recoil, just like it is more comfortable to accelerate to 100km from standstill over 15 seconds rather than 5 seconds! But the final energy of the car is the same.

As for your little friend and your gun, if he is a seasoned shooter and has that problem, I take it he is shooting prone?

Shooting Big Guns 101. Shoot a full power battle rifle without having it firmly against your shoulder. It will fly backwards at the speed of a fast marching pace. When it thus contacts you (rams you), you will hurt, likely bruise, no matter your body size. Thus people who shoot for the first time may be put off the sport as their fears of recoil are doubly confirmed when they hold the butt too lightly against their shoulder.

A slight lady shooting standing or kneeling with her rifle pressed firmly to her shoulder will absorb the recoil into her shoulder, and her torso will give and twist, with minimal or no hurt therefore to the shoulder. No such luck if she shoots prone.

Someone like myself shooting the same rifle in the standing position will just have a bit more local shoulder hurt to contend with, as my body is simply too big to recoil back as much as hers. My rifle butt will instead dig in more locally into my shoulder region. If I change to the prone shooting position I don't really notice much extra recoil therefore, but the wee girl will experience a relatively larger increase in recoil on shooting prone.

Just watch youtube funny videos of "I lent my wee girlfriend my big manly gun" and you usually see failure to make firm shoulder contact. All it says is, "her boyfriend is an idiot and will he never get a girlfriend who enjoys shooting with him".

Your wee friend should maybe shoot standing or kneeling, with a firm shoulder contact, even though he may feel safer handling a big gun lying prone. But things are not what they seem.

Of course, especially in shooting positions that allow your body to recoil back with the gun, having a gradual power release from the suppressed gun will allow your body to absorb the recoil more widely and move back with the gun. On an accuracy point, the suppressor allows you to hold the gun less firmly against your body, and thus less heartbeat oscillation is transmitted to it.

Hope this is helpful.

Originally Posted by timattalon

Yes the amount of energy in each direction is the same, but the impact on the shoulder is the speed of the rifle squared x the mass of the rifle. Adding a brake reduces the velocity by directling energy in a different direction. A suppressor slows the speed with which the gas can thrust the rifle back thus spreading the same amount of energy over a longer period of time (Reduces speed of the impact on the shoulder.) As the speed is squared in E=MC2 then reducing speed has a more significant effect on the impact on the shoulder. Total force (work done) remains the same but not as sudden or as violent.

E(KINETIC)=1/2 mv^2
Kinetic energy= half mass times velocity squared
E=mc^2 is relativity and deals with release of energy when mass is converted directly to energy in a nuclear reaction.
Energy= mass times the speed of light squared. Little relevance here.


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Originally Posted by Cordite

@timattalon,

I do not hear many say suppressors do not reduce recoil (which by definition have to mean felt recoil). The cooling and thus contraction of muzzle gases with resultant loss of pressure will reduce recoil. The slower release of gases will reduce felt recoil, just like it is more comfortable to accelerate to 100km from standstill over 15 seconds rather than 5 seconds! But the final energy of the car is the same.

As for your little friend and your gun, if he is a seasoned shooter and has that problem, I take it he is shooting prone?

Shooting Big Guns 101. Shoot a full power battle rifle without having it firmly against your shoulder. It will fly backwards at the speed of a fast marching pace. When it thus contacts you (rams you), you will hurt, likely bruise, no matter your body size. Thus people who shoot for the first time may be put off the sport as their fears of recoil are doubly confirmed when they hold the butt too lightly against their shoulder.

A slight lady shooting standing or kneeling with her rifle pressed firmly to her shoulder will absorb the recoil into her shoulder, and her torso will give and twist, with minimal or no hurt therefore to the shoulder. No such luck if she shoots prone.

Someone like myself shooting the same rifle in the standing position will just have a bit more local shoulder hurt to contend with, as my body is simply too big to recoil back as much as hers. My rifle butt will instead dig in more locally into my shoulder region. If I change to the prone shooting position I don't really notice much extra recoil therefore, but the wee girl will experience a relatively larger increase in recoil on shooting prone.

Just watch youtube funny videos of "I lent my wee girlfriend my big manly gun" and you usually see failure to make firm shoulder contact. All it says is, "her boyfriend is an idiot and will he never get a girlfriend who enjoys shooting with him".

Your wee friend should maybe shoot standing or kneeling, with a firm shoulder contact, even though he may feel safer handling a big gun lying prone. But things are not what they seem.

Of course, especially in shooting positions that allow your body to recoil back with the gun, having a gradual power release from the suppressed gun will allow your body to absorb the recoil more widely and move back with the gun. On an accuracy point, the suppressor allows you to hold the gun less firmly against your body, and thus less heartbeat oscillation is transmitted to it.

Hope this is helpful.

He is a seasoned shooter that weighs about 45kg dripping wet. And I agree that holding it tight back into the shoulder is what he is supposed to do. I am certain that he is as well, but the gun is nearly the same size he is.....and most of his shooting is at a bench standing up. The way I see it, the harder you pull the gun into your shoulder the more it makes the two masses (shooter and gun) into the same mass to be affected by recoil. Thus increasing the resulting rearwards acceleration by increasing the mass.

Originally Posted by Feather or Shoot

E(KINETIC)=1/2 mv^2
Kinetic energy= half mass times velocity squared
E=mc^2 is relativity and deals with release of energy when mass is converted directly to energy in a nuclear reaction.
Energy= mass times the speed of light squared. Little relevance here.


Sent from my GT-I8190T using Tapatalk

Yeah, looks like I got my formulae muddled. I knew it was energy = mass x velocity squared, but got the letters mixed up...... I havn't studied physics since the late 80s so perhaps a little rusty, but I do use a lot of arithmitic at my job so numbers and actual calculations are usually pretty easy for me....

Originally Posted by timattalon

He is a seasoned shooter that weighs about 45kg dripping wet. And I agree that holding it tight back into the shoulder is what he is supposed to do. I am certain that he is as well, but the gun is nearly the same size he is.....and most of his shooting is at a bench standing up. The way I see it, the harder you pull the gun into your shoulder the more it makes the two masses (shooter and gun) into the same mass to be affected by recoil. Thus increasing the resulting rearwards acceleration by increasing the mass.

@timattalon,
Yes, energy transfer butt-to-body is hampered by an air gap. And one misses out on the longer power transfer time offered by the suppressor.

The other one that affects felt recoil is force =mass x acceleration. A tight hug ads your weight to the equation, and slowing the acceleration by prolonging the gas escaping the suppressor both reduce the force on your shoulder.