Recoil

[Bullit]

I've often wondered technically what happens when a gun recoils. Does it start jumping before the bullet leaves the barrel? If so, how can the gun be accurate?

Anyone understand this and can explain what is happening for me?

[GregM]

As I understand it, the bullet does exert a force against the gun the instant it leaves the casing. This force is the product of the bullet's mass times its rate of acceleration. The acceleration is great, but the mass is so tiny that the resulting force is very, very small.

Most of the perceived recoil occurs after the bullet leaves the barrel, as the expanding gas behind the bullet pushes back against the muzzle. By this time the bullet is happily zinging its way downrange.

Hope I got that right ... physics never was my strong suit.

[selurcspi]

Every action has an equal and opposite reaction! Newton's Third Law



In recoil the gun comes straight back at the shooter; unless the muscles in the forearm are bigger than your thigh, there is insufficient strength to keep the wrist stable. This instability in the wrist causes it to bend; also, the shape of the grips cause the butt of the gun to pressure the heel of the hand first beginning the tipping motion, the bend in the wrist exacerbates the problem producing muzzle flip.

An interesting test for you (“WARNING” “WARNING” This is not for the inexperienced shooter and should only be performed with a single cartridge in the gun, “WARNING” “WARNING”) hold the gun upside down and fire it using your pinky on the trigger and the muzzle will flip downward bending your wrist in that direction.

[Ironbear]

I've often wondered technically what happens when a gun recoils. Does it start jumping before the bullet leaves the barrel? If so, how can the gun be accurate?

The short answer is that the gun starts moving when the bullet starts moving. It goes back to the old Newton's Law... For every action there is an equal and opposite reaction.

GregM got it partly right... F=ma (Force = mass X acceleration) except that it is the force (pressure created by the burning of power acting over an area) causing the acceleration (a = F/m). Since the mass of the gun is much larger than the mass of the bullet, the bullet accelerates much faster than the gun, and the distance the bullet moves in the time it takes to exit the barrel, is much farther than the distance the gun moves in the same time.

As to the accuracy issue. Accuracy requires consistency. If the bullet weight, power charge, shooter's grip, etc. are all the same; the gun will react the same way each time, and will shoot to the same point. Change anything and the results will change.

For example, at 30 feet, the trajectory difference, between a 1000 fps (feet per second) bullet and a 1500 fps bullet would be less than 1/10 of an inch. However, load those two different loads up, and you are likely to get more than 1/10 of an inch difference on the target!

If I can clarify anything, please ask.

[Ironbear]

In recoil the gun comes straight back at the shooter;
...

The gun will come straight back if and only if the line of force (ie. the bore axis) coincides with the center of gravity of the gun. Since the bore axis is typically above the cg (when held in a "normal" position ), recoil will always tend to rotate the muzzle up. Since the line of constraint (your hand and arm) are not on the bore axis, this only serves to exacerbate the rotation. Additional forces, such as those created by muzzle brakes and compensators, can be used to modify this reaction.

[Bullit]

So, do I have it right then that the bullet gets thrown upward a slight bit as it travels through the barrel? But, if all other conditions stay the same, the upward travel will be identical for every shot - so it is possible to get good groups.

On the other hand, for example, if you grip the firearm more tightly on one shot than the other, the effect of the recoil will be different and therefore will result in a more or less vertical pattern.

All the more reason for consistency, I see.

Thanks for the info guys!

[Seismic Sam]

An interesting test for you (“WARNING” “WARNING” This is not for the inexperienced shooter and should only be performed with a single cartridge in the gun, “WARNING” “WARNING”) hold the gun upside down and fire it using your pinky on the trigger and the muzzle will flip downward bending your wrist in that direction.

A more interesting test is go to Cokato when it's cold enough to freeze the balls off a brass monkey, give a bloody Limey a full loaded gun, and have him shoot it sidways: [i]"I say old boy, BUS CAPS, YO BEATCH!, I must strongly disagree with your opinion, GONNA CAP YO ASS!, and must accordingly respond by saying WHO's YER DADDY??, and besides that my bollocks are frozen to my leg, and Number 13. The Larch. The LAAARRRCCH. THE LAARRCH."i]

[Pat Cannon]

No more Monty Python for you, Sam!

[macphisto]

I really enjoy recoil and have come a long way from the time I rented a 1911 at Bill's and thought, "Wow, that's harsh! Wouldn't want to shoot that every day."

Now I can't get enough of the stuff. The best recoil generators in my current collection are my Colt .357 and Mossberg 12 gauge. The harshest-recoiling handgun I've shot to date was a .44 Mag, but I don't think I've reached my threshold. Who's got a gun I can shoot that will likely make me say, "Yikes, no thanks, I'm done!"?

[cobb]

Who's got a gun I can shoot that will likely make me say, "Yikes, no thanks, I'm done!"?

My Freedom Arms in a .475 Linebaugh?!?!

Some have said that after shooting my Lone Eagle in .358 Winchester, but I think the .475 is much more fun.

When do you want to play?

For those that say the 500 S&W, my .475 fits in any holster that a Ruger Blackhawk will fit into on your hip, a real handgun, not a revolver that is better carried with a sling, or the muzzle would slap you in your knees if you tried to wear it on your hip.

[macphisto]

When do you want to play?

You pick the place and I'll choose the time. Should I bring shooting gloves and a diaper?

[ttousi]

When do you want to play?

You pick the place and I'll choose the time. Should I bring shooting gloves and a diaper?

And a first aid kit

[macphisto]

I'm committed to not ever letting this happen to me: http://www.youtube.com/watch?v=wwLQewe4TrY

I think the fact that I weigh over a hundred pounds improves my chances of success.

[cobb]

I'm committed to not ever letting this happen to me: http://www.youtube.com/watch?v=wwLQewe4TrY

Not even close.

[Seismic Sam]

You can commit all you want to mac - when you pull the switch on a handload that puts a 325 grain bullet out the pipe at 1930 FPS from a Smith 500, reality skips like a bad internet feed. I shoot 50 rounds at a time with "wimpy" 1450 FPS loads (half the time one handed), and it's just good clean fun. You pull the trigger, the thing goes KABOOM and comes back at you hard, and you're fine. With the 1900+ loads, you pull the trigger and there is a perceptible GAP in reality where the thing starts to come back, and then it's all the way back and your hand feels all funny. BTW - I'm 6'3" and 240. Does that makes me 2.5 times more attractive than a 100 pound woman in a bikini shooting the same gun?

Ummmm..... NOTTTTTTT!!!!!