1911Tuner
Moderator Emeritus
Cowboy...Sure. Not only is the dwell time signifigant...but the force requirement between the two is a whole different critter. Force forward is force backward.
Bullet weight & recoil
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That is what I said!
That is why I said think in terms of momentum. Inertia being a measurement of a body's resistance to changes in momentum.
So if you think in terms of momentum imparted to a projectile, the projectile with higher momentum will create higher recoil in a given weight firearm.
Since all projectiles start with virtually 0 momentum before being fired , the higher the momentum reached by a given projectile, the greater the inertia that is overcome.
While momentum is very easy to compute with readily available figures given for most cartridges..
So the most practical way to think of it and put it to use in regards to firearm projectiles is to simply determine the momentum the fired projectile has.
The higher the number the more recoil is imparted fighting the inertia of the projectile.
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1911Tuner
Moderator Emeritus
Yup. Missed it. Dog feedin' time. 17 of'em...13 in the house... Gotta hit and run this time of the day.
Yup Yup. Mass X Velocity. Theoretical equal momentums...absent outside force. Very little practical difference even with outside force.
tjj
Member
"That is what I said!
That is why I said think in terms of momentum. Inertia being a measurement of a body's resistance to changes in momentum.
So if you think in terms of momentum imparted to a projectile, the projectile with higher momentum will create higher recoil in a given weight firearm.
Since all projectiles start with virtually 0 momentum before being fired , the higher the momentum reached by a given projectile, the greater the inertia that is overcome.
While momentum is very easy to compute with readily available figures given for most cartridges..
So the most practical way to think of it and put it to use in regards to firearm projectiles is to simply determine the momentum the fired projectile has.
The higher the number the more recoil is imparted fighting the inertia of the projectile. "
Kinda. Inertia is the resistance of a stationary mass to motion. Momentum is the moving mass's resistance to stopping. Front door - back door sorta thing. I think most everyone intuitively knows what is happening but it's difficult to describe in words.
That is why I said think in terms of momentum. Inertia being a measurement of a body's resistance to changes in momentum.
So if you think in terms of momentum imparted to a projectile, the projectile with higher momentum will create higher recoil in a given weight firearm.
Since all projectiles start with virtually 0 momentum before being fired , the higher the momentum reached by a given projectile, the greater the inertia that is overcome.
While momentum is very easy to compute with readily available figures given for most cartridges..
So the most practical way to think of it and put it to use in regards to firearm projectiles is to simply determine the momentum the fired projectile has.
The higher the number the more recoil is imparted fighting the inertia of the projectile. "
Kinda. Inertia is the resistance of a stationary mass to motion. Momentum is the moving mass's resistance to stopping. Front door - back door sorta thing. I think most everyone intuitively knows what is happening but it's difficult to describe in words.
hammerklavier
Member
1911Tuner wins the physics prize, good explanations.
Don't forget there are two components to recoil, the force, and the velocity. With velocity it's like a shove verses a punch, both can have the same force, but the punch hurts more.
Don't forget there are two components to recoil, the force, and the velocity. With velocity it's like a shove verses a punch, both can have the same force, but the punch hurts more.
1911Tuner
Moderator Emeritus
Well...I hesitate to use muzzle velocity. While it's certainly related and can be used as a rough indicator...it's really not definitive. Basically, it boils down to the rate of acceleration and the force required to achieve that rate.
The force is generated by the expanding gasses and the pressure that they develop. Since pressures peak surprisingly early, that's the point at which peak force is applied, and hence the peak recoil impetus. As long as the bullet is being pushed, the brechblock is being pushed...but after the peak...the rate of acceleration isn't as high as it was at the peak.
Another reason is that, with some powders and barrel lengths...it's completely possible for the bullet to be moving faster before it exits the muzzle than it does at the muzzle. Hypothetically...a rifle barrel that's long enough to let the gasses run out of steam...recoil will be produced without the bullet ever leaving the muzzle.
That was demonstrated several years ago by a gun writer...can't remember who...when he lopped off a rifle barrel an inch at a time, and tested velocities with different powders suitable for the caliber...ranging from fast to slow. With a couple of the faster numbers, the rifle actually produced higher velocities with shorter barrel lengths. So...more barrel length doesn't always produce higher velocities. I have to at least suspect that the same thing happens with pistols. For instance...with the .45 ACP...you'll notice that Bullseye sometimes produces lower velocities at pretty much equal pressure levels than a slower but equally suitable powder for the cartridge. More...in my own experience...I've found that sometimes recoil is noticeably sharper with a quick powder, even though the chronograph shows that the velocities are lower.
One thing is for sure. Ballistics is an altogether interesting hobby and a fascinating science.
I always thought most of the Recoil was from the expanding/exiting high-pressure Gasses leaving the Barrel behind the Bullet...after the Bullet has left.
Lay down any old mostly full or plum full Oxy-Acetylene Oxygen Jug, wham off the Valve with a Sledge Hammer, and, that fifty-sixty pound Jug takes off like-a-Rocket...going right through Walls, Cars, Bulk-Heads, you name it.
Imagine that as 'Recoil' where no 'projectile' is even present.
The Gasses exiting behind a Bullet, are often of greatly higher pressure than the 3,000 or so PSI of Bottled Oxygen.
Lay down any old mostly full or plum full Oxy-Acetylene Oxygen Jug, wham off the Valve with a Sledge Hammer, and, that fifty-sixty pound Jug takes off like-a-Rocket...going right through Walls, Cars, Bulk-Heads, you name it.
Imagine that as 'Recoil' where no 'projectile' is even present.
The Gasses exiting behind a Bullet, are often of greatly higher pressure than the 3,000 or so PSI of Bottled Oxygen.
1911Tuner
Moderator Emeritus
Oyeboten...
With some high pressure, large capacity bottlenecked rifle cartridges, it's possible for the recoil produced by the gasses following the bullet to equal or maybe even exceed that from the bullet itself. The big bottle/small neck creates a venturi effect that is essentially a crude rocket.
Not long ago, on a similar discussion, I had a member load up a .45 ACP blank with 10 grains of Bullseye held in place by a tuft of cotton to show that the slide on a 1911 could be made to move with a small level of force and without a bullet. It didn't move far...but it did move.
The one factor that many fail to consider is that the the mass of the burning gasses equals the mass of the unburned powder, and that during the mechanical action/reaction event...while the system is closed...that mass is added to the mass of the bullet. In effect, a 150 grain bullet pushed by 50 grains of powder essentially means that there's a 200 grain "projectile" hurtling down the bore. So, a combination in which the gas jet effect recoil exceeds that of the actual closed system event is pretty rare.
I've very often had a hard time convincing some people that the gun is in full recoil while the bullet is still in the barrel...that with the term "Equal and Opposite" the operative word is "Equal."
With some high pressure, large capacity bottlenecked rifle cartridges, it's possible for the recoil produced by the gasses following the bullet to equal or maybe even exceed that from the bullet itself. The big bottle/small neck creates a venturi effect that is essentially a crude rocket.
Not long ago, on a similar discussion, I had a member load up a .45 ACP blank with 10 grains of Bullseye held in place by a tuft of cotton to show that the slide on a 1911 could be made to move with a small level of force and without a bullet. It didn't move far...but it did move.
The one factor that many fail to consider is that the the mass of the burning gasses equals the mass of the unburned powder, and that during the mechanical action/reaction event...while the system is closed...that mass is added to the mass of the bullet. In effect, a 150 grain bullet pushed by 50 grains of powder essentially means that there's a 200 grain "projectile" hurtling down the bore. So, a combination in which the gas jet effect recoil exceeds that of the actual closed system event is pretty rare.
I've very often had a hard time convincing some people that the gun is in full recoil while the bullet is still in the barrel...that with the term "Equal and Opposite" the operative word is "Equal."
twoclones
Member
Without all the math... I've let friends shoot my .500 S&W revolver with 325 gr. rounds first then 440 gr. rounds next and they sure notice the difference in recoil. It feels like you've moved up to a larger caliber!
Recoil energy and felt recoil are two different things.
Recoil energy is a precise, physical quantity that is a function of the weight (mass) of the bullet, the weight (mass) of the powder charge, the muzzle velocity of the bullet, the muzzle velocity of the powder gases, and the weight (mass) of the gun. If you have those quantities for a given load in a given gun, you can calculate the amount of recoil energy produced when that load is fired in that gun.
Felt recoil is a subjective matter. It's how you experience the recoil, and it's really something that only you can decide for yourself. In general, for example, a lighter, fast bullet may produce recoil energy comparable to that of a heavier, slower bullet. But the recoil energy of the load with the lighter bullet will be manifest in a shorter pulse (distributed over a shorter period of time), while that with the heavier bullet will be distributed over a longer period of time. Depending on how you, personally experience these two types of recoil pulses, one may seem greater to you than the other, even though they really have similar recoil energy.
If you're interested, you can calculate the recoil energy of a given load using the following formula:
WG = Weight of gun in pounds
WB = Weight of bullet in grains
WP = Weight of powder charge in grains
VB = Muzzle velocity of bullet in f/s
I = Interim number (Recoil Impulse in lb/sec)
VG = Recoil velocity of gun (f/s)
EG = Recoil energy of gun (ft lb)
I = [(WB * VB) + (WP * 4000)] / 225218 VG = 32.2 * (I / WG)
EG = (WG * VG * VG) / 64.4
This formula is from the Q&As at http://www.frfrogspad.com/miscella.htm (specifically the question about why some guns of the same caliber kick harder than others). John Schaefer (FrFrog) notes that, "..."4000" is the nominal velocity of the powder gases at the muzzle for commercial smokeless powder and the observed range is between 3700 and 4300 f/s. It is sometimes stated as 4700 in some sources but this is based on observations of artillery, not small arms...."
Recoil energy is a precise, physical quantity that is a function of the weight (mass) of the bullet, the weight (mass) of the powder charge, the muzzle velocity of the bullet, the muzzle velocity of the powder gases, and the weight (mass) of the gun. If you have those quantities for a given load in a given gun, you can calculate the amount of recoil energy produced when that load is fired in that gun.
Felt recoil is a subjective matter. It's how you experience the recoil, and it's really something that only you can decide for yourself. In general, for example, a lighter, fast bullet may produce recoil energy comparable to that of a heavier, slower bullet. But the recoil energy of the load with the lighter bullet will be manifest in a shorter pulse (distributed over a shorter period of time), while that with the heavier bullet will be distributed over a longer period of time. Depending on how you, personally experience these two types of recoil pulses, one may seem greater to you than the other, even though they really have similar recoil energy.
If you're interested, you can calculate the recoil energy of a given load using the following formula:
WG = Weight of gun in pounds
WB = Weight of bullet in grains
WP = Weight of powder charge in grains
VB = Muzzle velocity of bullet in f/s
I = Interim number (Recoil Impulse in lb/sec)
VG = Recoil velocity of gun (f/s)
EG = Recoil energy of gun (ft lb)
I = [(WB * VB) + (WP * 4000)] / 225218 VG = 32.2 * (I / WG)
EG = (WG * VG * VG) / 64.4
This formula is from the Q&As at http://www.frfrogspad.com/miscella.htm (specifically the question about why some guns of the same caliber kick harder than others). John Schaefer (FrFrog) notes that, "..."4000" is the nominal velocity of the powder gases at the muzzle for commercial smokeless powder and the observed range is between 3700 and 4300 f/s. It is sometimes stated as 4700 in some sources but this is based on observations of artillery, not small arms...."
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