16” barrel recoil

[Sambini]

Hello, 

How much recoil would a 16” barrel have versus say an 18”-20” barrel? 

[COBrien]

In my experience, felt recoil is more a function of gas system, buffer system, and muzzle device.

[COBrien]

I meant to add this example, but I waited too long to edit my post...

My DPMS LR-308T, with 16" HBAR, carbine-length gas system, DPMS-standard buffer and spring, and DPMS-standard flash hider, was a beast when I got it -- the recoil was quite substantial.

I added a heavy buffer and Armalite spring from Slash, and a Smith Enterprise "Good Iron" muzzle brake and it felt like a completely different rifle. Mild-mannered and well-behaved.

I then took it one step further and added an SLR adjustable gas block (which may make it possible to revert back to the DPMS-standard buffer and spring), but I haven't had an opportunity to get it out and tune it all up just yet.

[ARTrooper]

1 hour ago, Sambini said:

Hello, 

How much recoil would a 16” barrel have versus say an 18”-20” barrel? 

very little difference. might feel a little snappier, but there are ways to calm that down, and a lot of people still would have trouble feeling the difference.

[edgecrusher]

3 hours ago, COBrien said:

In my experience, felt recoil is more a function of gas system, buffer system, and muzzle device.

This

[Robocop1051]

These guys all said it. Recoil is recoil… You can’t change that it is the reaction of an action. That’s the physics of it. The mass and velocity of the projectile is what determines the “recoil”. It has nothing to do with barrel length. 

Recoil can be mitigated by controlling the gas system and the cyclic rate of the action. This doesn’t actually “reduce recoil“ but it does absorb the recoil into the action of the rifle.  A shooter actually feels to “recoil’s“ back to back, within a very short time. The first is the firing of the cartridge, and the second is the bolt carrier group and buffer slamming into the rear of the stock assembly. 

Controlling the gas and spring weight doesn’t reduce the recoil, but it does absorb a percentage of that recoil into the operating system of the rifle. The recoil still exist, just inside the rifle.

Adding a brake assists in braking the direction of the recoil by using the expanding gassed against the rearward impulse. Just like most compensators use the gases to maintain muzzle alignment. 

 The only other way to reduce “felt recoil“ if to add weight. Technically a 16 inch bull barrel would reduce more felt recoil than a 20 inch pencil white barrel. The heavier the rifle, the more energy will be absorbed by the weight before that energy will transfer to the shooter. 

Somebody correct me here if I’m wrong

[unforgiven]

I would concur. 

[98Z5V]

13 minutes ago, Robocop1051 said:

These guys all said it. Recoil is recoil… You can’t change that it is the reaction of an action. That’s the physics of it. The mass and velocity of the projectile is what determines the “recoil”. It has nothing to do with barrel length. 

Recoil can be mitigated by controlling the gas system and the cyclic rate of the action. This doesn’t actually “reduce recoil“ but it does absorb the recoil into the action of the rifle.  A shooter actually feels to “recoil’s“ back to back, within a very short time. The first is the firing of the cartridge, and the second is the bolt carrier group and buffer slamming into the rear of the stock assembly. 

Controlling the gas and spring weight doesn’t reduce the recoil, but it does absorb a percentage of that recoil into the operating system of the rifle. The recoil still exist, just inside the rifle.

Adding a brake assists in braking the direction of the recoil by using the expanding gassed against the rearward impulse. Just like most compensators use the gases to maintain muzzle alignment. 

 The only other way to reduce “felt recoil“ if to add weight. Technically a 16 inch bull barrel would reduce more felt recoil than a 20 inch pencil white barrel. The heavier the rifle, the more energy will be absorbed by the weight before that energy will transfer to the shooter. 

Somebody correct me here if I’m wrong

That fucking nails it, perfectly, in one post.  

[ARTrooper]

Yup, Rob basically covers it all.

 

I think some people see muzzle rise as recoil though also. this is incorrect though. I would describe muzzle rise as more of a side affect of recoil.

the barrel sits in line with the bcg and buffer assembly all above the shooters grip. when the rifle recoils, the grip is basically a pivot point causing the muzzle to rise instead of the whole rifle going straight back.

while most rifles are about the same in this, you can really see the difference in handguns. a handgun with a low bore axis, meaning the barrel being lower and closer to the firing hand, will have less muzzle rise and be quicker back on target than a handgun with a higher bore axis. the best example of this is a Chiappa Rhino versus a regular revolver. The Rhino's barrel lines up with the bottom of the cylinder instead of the top of the cylinder like most revolvers. There are other semi auto pistols out there currently being designed to have low bore axis. 

with bore axis, think of a lever in physics. a higher bore axis acts like a longer lever making that barrel easier to move, while a lower bore axis acts like a short lever making it more difficult to move.

That's all fine and dandy with pistols, but in an AR you basically have the same bore axis no matter what. So how do you try and limit muzzle rise since you can't change the bore axis? Weight and gas management. 

With weight, if you are front end heavy, this will help with muzzle rise because takes more force to make the heavy front rise in the first place. Now this is often times seen in long range bolt actions, but probably not the best idea for an already heavy 308AR platform. You would have to add a good couple of pounds to the front, which would quickly turn your rifle in to a 12+ pound rifle. and being front heavy, it would be exhausting to carry and shoulder for any period of time. 

The best bet these days to deal with muzzle rise is gas management. And I am talking about how the gas is directed as it exits the barrel. Compensators have long been used to tame muzzle rise, as the barrel wants to rise up, direct the gas to give it some force back down. A simple concept of thrust. Now with many designs the downside is you have gasses going up into the line of sight of your optics or sights, which can affect follow up shots. Luckily these days many good muzzle brakes have compensator slots or holes in them in different directions to prevent all the gasses from going up where you don't want them. I recently purchased one of many such items, a VG6 Precision brake. With this one, the majority of the gasses are directed out the sides, helping with the felt recoil, while a small amount goes through slits in the top to help tame muzzle rise. but even by limiting that felt recoil wanting to push back against that pivot point, that also helps with the muzzle rise remember. ?

[bubbas4570]

I know this is apples to oranges, BUT my 5.56 FUR is much easier recoiling (felt recoil) with the rifle gas system than either of my other 5.56 rifle with either carbine or mid length gas systems. The impulse is "slower" with the rifle length system methinks. The barrel weights are this.....HBAR with the rifle, and M4 with the others.

[bubbas4570]

And I forgot to add this in, but they are all 16".

 

And my 308AR is a 16" HBAR with a rifle length gas system......it's felt recoil was less than my Scout rifle.