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3/20/2017 5:03:23 PM
Posted: 12/20/2001 8:33:11 AM EDT
A co-worker asked me what causes muzzle climb on rifles. We know it has something to do with gas pressure coming out of the muzzle. But we don't know exactly what causes it. Any info would be great.

Thanks!
Link Posted: 12/20/2001 8:43:09 AM EDT
Primary Recoil starts the split second the primer ignites. It starts the chain of reactions that all of us describe as recoil. The primer explodes causing the powder to ignite and burn. This creates the hot expanding gas that creates the pressure that forces the bullet down the barrel. starts the split second the primer ignites. It starts the chain of reactions that all of us describe as recoil. The primer explodes causing the powder to ignite and burn. This creates the hot expanding gas that creates the pressure that forces the bullet down the barrel. starts the split second the primer ignites. It starts the chain of reactions that all of us describe as recoil. The primer explodes causing the powder to ignite and burn. This creates the hot expanding gas that creates the pressure that forces the bullet down the barrel. Enter Newton's Third Law of thermodynamics:

For every action there is an equal and opposite reaction.

Here we are talking about the recoil while the bullet is traveling inside the barrel.

Secondary Recoil, better known as muzzle blast, takes place when the bullet exits the barrel and releases the hot burning compressed gas. This gas is expanding rapidly in all directions. This makes the rifle like a rocket, forcing it back and up with it's greatest force. Note: The reason for muzzle jump is quite simple. The centerline of the bore is above your shoulder.

Mike

Link Posted: 12/20/2001 8:44:44 AM EDT
Its becaues the centerline of the barrel is higher than the centerline of the butt stock so when the barrel tries to recoil straight back, its rearward motion is opposed by a force (you) acting against the butt stock. since the two forces are not aligned with each other, there is an upward movement at the muzzle.
Link Posted: 12/20/2001 8:59:32 AM EDT
Newtons Third Law of Motion: "If a force is acted upon the 1st body by a 2nd body, an equal and opposite force is exerted on the 2nd Body by the 1st Body."

In this case the force of the gas is exerted on the bullet which causes it to accelerate down the bore of the barrel..picking up speed. But at the same time force is being exerted against the rifle to accelerate it in the opposite direction of the bullet. This is called Recoil.

As for Muzzle Flip. If you hold up (most rifles and shotguns) you will notice that the butt stock is below the barrel. When the Rifle or Shotgun goes into recoil, this slight drop in the buttstock acts as a "moment arm". That is: the recoil of the rifle forces the rifle backwards, but the buttstock being placed against your should resists this backwards motion, but since the buttstock is slightly BELOW the line of the barrel, the backwards motion (or force) is not entirely canceled out and the rifle (or shotgun) will swing upwards.

Here is a simple example. Open a door so that its edge directly faces you (90 degrees). place your hand on the door edge and push it. Notice however hard you push on the door..it pushes back on your hand with an equal force ? (be careful when doing this!).
You can think of the door in this position as similating a centerline stock on a rifle.
The force of your hand against the door being the gas pressure inside the barrel.

Now..move the door just a little bit towards the doorway so that the door edge is very slightly misaligned with your hand. (that is the door is open at an angle slightly less than 90 degrees).

Now push VERY GENTLY against the edge of the door. Notice how the door swings. The force exerted by the door against your hand doesn't quite cancel out the force that you are exerting against the door.

This similates a normal stock. One in which the buttstock has a slight drop to it (below the barrel).
Link Posted: 12/20/2001 10:00:52 AM EDT
Originally Posted By Bostonterrier97:
Newtons Third Law of Motion: "If a force is acted upon the 1st body by a 2nd body, an equal and opposite force is exerted on the 2nd Body by the 1st Body."

Where and the heck were you when the rest of us were cutting that...that class ???
I'm not even sure you should use some of those words as women and children also use this site.
Weel maybe it is alright - you only have "two body's in motion." But if you had three....


Now how does a muzzle-brake work ??

Link Posted: 12/20/2001 10:33:14 AM EDT
5subsir5 asks:Now how does a muzzle-brake work ??


Muzzle Brakes redirect the flow of hot burning gasses 360°; thus neutralizing the "rocket force" (see previous post) and controlling the gasses released in such a way as to reduce the amount of energy aimed back at you.

Mike

Link Posted: 12/20/2001 10:48:18 AM EDT

Originally Posted By ECS:
Its becaues the centerline of the barrel is higher than the centerline of the butt stock so when the barrel tries to recoil straight back, its rearward motion is opposed by a force (you) acting against the butt stock. since the two forces are not aligned with each other, there is an upward movement at the muzzle.



I'll second this notion.

Note the minimal muzzle rise of the AR configuration. The top of the AR buttstock is ABOVE the centerline of the barrel, causing the recoil to go directly back in to the shoulder.

Comparatively, with the centerline of teh barrel ABOVE the top of teh buttstock, the rilfe recoils back and up once the backward motion is offet by the shoulder, making the rifle act like a hinge, with the shoulder being the pivot point.
Link Posted: 12/20/2001 12:31:55 PM EDT
Thanks guys! It makes sense to me. I'm off to see Todd now.

Brad
Link Posted: 12/20/2001 12:52:42 PM EDT
For every action, there is an equal and opposite reaction.


The weight of the projectile and it's energy vs. the weight of the firearm.

Don't get confused, however, with the energy measured in foot-pounds vs. the weight of the firearm. The bullet is the mass in the equation.
Link Posted: 12/20/2001 1:15:47 PM EDT

Originally Posted By mr_wilson:
5subsir5 asks:Now how does a muzzle-brake work ??


Muzzle Brakes redirect the flow of hot burning gasses 360°; thus neutralizing the "rocket force" (see previous post) and controlling the gasses released in such a way as to reduce the amount of energy aimed back at you.

Mike

I of course knew the answer all the time and was just testing you !!


Link Posted: 12/20/2001 1:37:15 PM EDT
Actually a muzzle brake directs gas about 90 degrees. 360 degrees is a full circle, and any muzzle brake doing that would make no sense.

Most brakes direct gas upward thus cancelling out the upward tendancy of the barrel.
Link Posted: 12/20/2001 6:33:26 PM EDT
Muzzle brake...

Imagine a large guy is running toward you, like the propelling gas traveling down a barrel. If you're standing still--like the ports on a brake are standing still on the barrel--and you bump the guy running just enough to slightly change his direction, you'll be knocked in the direction he's running. But, if you were the muzzle brake, you'd be conected to the barrel. And because the running guy you deflected pushes on you, you push on the barrel in the same direction the guy is going. Therefore, this pushing forward on the barrel causes some of the rearward force of the recoil to be cancelled, or braked.

To be more exact with the alalogy, the gas behind the bullet is trying to swell (expand)outward just as much as it ties to expand down the barrel. When the outwardly expanding gas reaches a port in the brake, it naturally tries to escape through that port. But, this gas still has a down-the-barrel speed, like the guy running toward you. So, the gas escaping through the port pushes against the wall of the port in the same direction the gas is going, which is down the barrel. So, the muzzle brake pulls on the barrel to cancel some recoil.

Make sense?
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