Recoil-less AR build? (For the wife)

[HammsBeer]

A soft shooting AR would be a 20" barrel with a rifle length gas system and rifle length buffer. No comp or brake, 5.56 is loud enough already. Anything shorter in barrel or buffer length will increase recoil and noise.

 

[MistWolf]

A shorter barrel will have less recoil (if the weight of three rifle remains the same) not more, because velocity will be reduced

 

[readyeddy]

I feel like I'm sitting in the back row of high school physics.

How about shooting the gun in zero gravity? No air pressure so no recoil. But then the gun is weightless, so recoil increases.

Maybe shoot the cheap steal cased stuff that's under powered and soft shooting.

 

[barnbwt]

Mistwolf, don't forget that powder gas velocity is a very significant component of rifle cartridge recoil --especially in short barrels. You might get some reduction, but again, the bark will get so bad as to become a bite itself. I also thought short AR gas systems have to cycle more violently, in order to harvest enough "go" from the barrel gasses to cycle reliably.

For a soft shooter AR anyone will love shoot, why doesn't the OP sign up for a can? Wait times are supposed to be falling rapidly these days...

"There are many brakes that make that advertisement. However, not a single one of them can overcome the laws of physics. If any extra energy is directed forward, then more force is directed backwards."
The corollary to this statement is that the recoil of an AR is a far, far weaker stress on the shooter than the muzzle blast, otherwise a forward-directed brake would make shooting unbearable. Despite unavoidably increasing recoil (this type of brake is also called a recoil booster in machine guns, for cryin' out loud!) shooters proclaim the rifles are "more controllable" and "softer shooting." Softer on the ears, maybe

TCB

 

[HammsBeer]

Typically the shorter the barrel, the more unburnt powder there is to burn at the muzzle. Granted a good flash hider can stifle some of that, but you still have higher gas pressures coming out in shorter barrels which contributes to noise pressure.

The shorter the buffer tube, the shorter the space for the buffer to slow down before bottoming out in the rear. Also, the rifle length buffer weighs more than most of the heavy carbine buffers, helping to slow down the cycling velocity of the action.

Think of a pistol, if the caliber remains the same, then the smaller the gun the more recoil you absorb. If you shrink the size of the rifle, it has less room and weight to burn powder or cycle the action.

 

[Autopistola]

Well I'm pretty sure she wants a collapsible stock for her small frame, so the Vltor A5 would be the softest recoiling in that regard. Perhaps the increased recoil from a linear comp could be offset by a shock absorbing stock or special buffer.

My personal AR is 18" rifle gas, rifle buffer. I don't notice recoil much in the 10lb (with optic) rifle, just a change in sight picture. It has the dreaded Bushmaster mini-Y comp on it (for now), the concussion is awful if you are anywhere near other stuff.

 

[MistWolf]

Mistwolf, don't forget that powder gas velocity is a very significant component of rifle cartridge recoil --especially in short barrels...

The velocity of the gas exiting the muzzle is the same whether it exits a 7 inch or 24 inch barrel and that constant is roughly 5700 fps. The pressure has nothing to do with recoil. It's velocity and mass

Typically the shorter the barrel, the more unburnt powder there is to burn at the muzzle. Granted a good flash hider can stifle some of that, but you still have higher gas pressures coming out in shorter barrels which contributes to noise pressure

Actually, the powder burns completely in a very short distance. The reason there is a larger muzzle flash for a shorter barrel is because the gas is under greater pressure and temperature. When it mixes with the oxygen rich air as it exits the muzzle, the gas itself ignites. A flash suppressor works by dispersing, cooling and mixing the hot gas from the muzzle with the fresh air at a slower rate

The shorter the buffer tube, the shorter the space for the buffer to slow down before bottoming out in the rear

This is not so. The carrier has to travel the same distance regardless of buffer tube length. What changes is how short the spring is when it's fully compressed. The ratio of relaxed length to compressed length is greater in a carbine carbine tube assembly than it is in an A5 or rifle tube assembly

Think of a pistol, if the caliber remains the same, then the smaller the gun the more recoil you absorb. If you shrink the size of the rifle, it has less room and weight to burn powder or cycle the action.

Free recoil is affected by the mass of the bullet, powder charge & rifle and the velocity of the bullet and gasses exiting the muzzle. Action type does not increase or decrease how much recoil is generated. It can change vector and duration, which is what we call "felt recoil". How much recoil the exiting gas adds is the same whether the barrel is short or long. However, a longer barrel lets the bullet accelerate to a higher velocity and higher velocity results in higher recoil. So, an 8 lbs AR launching a bullet at a lower velocity due to a shorter barrel, has less recoil than an 8 lbs AR launching a bullet at higher velocities due to a longer barrel.

When the BCG of the AR opens, it stores some of the recoil energy and does not fully transfer it to the rifle and thus to the shooter, until it reaches the limit of it's rearward motion. At that point, the energy is stored in the spring. When the spring is relaxes, that energy is released, pushing the BCG forward and the rifle back. What's happening is part of the recoil energy is delayed and redirected, softening recoil, but not reducing it

 

[d2wing]

I have a 16 inch carbine and a 20 inch rifle. While total recoil is a wash, the rifle feels less sharp. The shorter gas tube in the carbine means higher and quicker pressure on the BCG and spring. An H2 buffer helps but it is still sharper than the rifle. The rifle is smoother and quieter to shoot and the recoil is spread over more time so it feels less.

 

[MistWolf]

in short barrels...You might get some reduction, but again, the bark will get so bad as to become a bite itself...

I know this is a bit late, but I wanted to address this issue. I meant to in my earlier post, but it got lost in the shuffle. The point barnbwt makes here is very important. Many shooters will tell you a firearm kicks harder simply because it's louder and has more concussion. barnbwt is right- the extra concussion of a very short barrel increases the perception of recoil although the recoil is reduced. This is why I don't like short barrels on youth model centerfire rifles

 

[Inebriated]

I have a 16 inch carbine and a 20 inch rifle. While total recoil is a wash, the rifle feels less sharp. The shorter gas tube in the carbine means higher and quicker pressure on the BCG and spring. An H2 buffer helps but it is still sharper than the rifle. The rifle is smoother and quieter to shoot and the recoil is spread over more time so it feels less.

This is why I'm a fan of Dissipators from a comfort standpoint. Rifle-length gas, carbine-length barrel. Very smooth shooters. If I wanted to go for the minimum amount of recoil, I'd look at going with a Dissipator upper.

 

[Captain33036]

Sorry, if this was mentioned, or obvious, but...a rubber pad on the AR stock might make it a bit more comfortable for her.

I definitely agree with longer barrel, no comp and different buffer. All excellent ideas.

Hope this helps