You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
Bullet weight and recoil?
- Thread starter USNRet93
- Start date
NoSecondBest
New member
For every action there is an equal and opposite reaction. What ever muzzle energy is going out the front is going to generate the same going back.
Muzzle energy (kinetic) equals one-half the mass of the bullet times velocity squared. E=.5mvv
Load them up and shoot them over a chronograph. Measure the velocity of several shots to get an average. A little math and you'll have your answer. The greater muzzle energy will have the greater recoil.
Load them up and shoot them over a chronograph. Measure the velocity of several shots to get an average. A little math and you'll have your answer. The greater muzzle energy will have the greater recoil.
Gary Wells
New member
Everything else being equal, the heavier bullet will have more recoil than the lighter bullet.
sigarms228
New member
IMO that is a more complicated question beyond the pure physics than it may first seem as recoil experiences are somewhat subjective in a semi automatic pistol due to the characteristics of the recoil. I find I like shooting 147 gr vs 124 in 9MM as it seems to be more of a push and less of a snap that 124.
I don't think this question has a simple answer.
The "power factor" that is used to determine classes in USPSA and IDPA competition is a measure of projectile momentum. It is based on a simple product of projectile mass and muzzle velocity (momentum=mv), specifically projectile mass in grains x muzzle velocity in feet per second divided by 1000.
Conservation of momentum is an important law of physics governing the interaction and movement of bodies. This law would suggest that the momentum imparted to the projectile by the expansion of gasses in the barrel will equal the momentum imparted to the slide.
But perceived recoil may depend on more than just slide momentum even when shooting various cartridges from the same handgun. The velocity imparted to the slide might significantly affect the perceived recoil. Projectiles that leave the barrel more slowly might therefore result in somewhat slower slide velocity.
Here is a somewhat interesting article which attempted to control for barrel length and pistol weight, measuring magnitude of recoil based on the extent of pistol movement when it was fired clamped into a Ransom rest:
http://www.handgunsmag.com/editorial/recoil-comparison-pistol-competition-cartridges/137951#
The authors also attempted to control for different powders and powder charges used in different commercial loads by firing hand loaded cartridges that had been charged with the same powder.
They then adjusted the hand loads to match the same power factor comparing .45 ACP to .40 S&W and 9 mm Luger to 38 Super.
They found that when the power factor was matched the recoil, as measured by Ransom rest pistol movement was virtually identical for .45 ACP compared to .40 S&W, and for 9mm Luger compared to 38 Super. This makes sense to me since they controlled for pistol weight. Therefore the momentum imparted by the powder charge to the projectile (power factor) would equal the momentum imparted to the pistol which would result in equal movement of the pistol within the rest, given the same pistol weight.
The measured recoil of .45 ACP and .40 S&W was quite similar even when powder charge and power factor were not adjusted for. But as many who shoot both calibers would say, .45 ACP recoil is often perceived as a slower "push" whereas .40 S&W recoil is perceived as a sharper "snap". The authors opined that the faster .40 S&W projectile which dwells in the barrel a shorter time than the .45 ACP projectile, produces a faster recoil impulse. This makes sense to me.
If you have an accurate measure of muzzle velocity, projectile momentum is easy to calculate for any given projectile mass. It is momentum in lb-ft/sec equals projectile mass in grains times muzzle velocity in feet per second divided by 7000. If you compute the projectile momentum for similar 9 mm Luger loads (FMJ from the same maker, for example) for 115, 124, and 147 grain projectiles, you will usually find that the momentum increases by 0.8-1.0 lb-ft/sec as you step up each projectile weight. That would imply that the recoil will increase with increasing projectile mass. But those heavier projectiles also have lower velocity and dwell in the barrel longer, so the velocity imparted to the slide might be less.
For what it is worth I have heard some claim that 115 grain produces more recoil than 124 grain when shot from the same gun, and some the opposite. And I have heard some say the 147 grain shoots softer than 124 grain, and some the opposite.
The "power factor" that is used to determine classes in USPSA and IDPA competition is a measure of projectile momentum. It is based on a simple product of projectile mass and muzzle velocity (momentum=mv), specifically projectile mass in grains x muzzle velocity in feet per second divided by 1000.
Conservation of momentum is an important law of physics governing the interaction and movement of bodies. This law would suggest that the momentum imparted to the projectile by the expansion of gasses in the barrel will equal the momentum imparted to the slide.
But perceived recoil may depend on more than just slide momentum even when shooting various cartridges from the same handgun. The velocity imparted to the slide might significantly affect the perceived recoil. Projectiles that leave the barrel more slowly might therefore result in somewhat slower slide velocity.
Here is a somewhat interesting article which attempted to control for barrel length and pistol weight, measuring magnitude of recoil based on the extent of pistol movement when it was fired clamped into a Ransom rest:
http://www.handgunsmag.com/editorial/recoil-comparison-pistol-competition-cartridges/137951#
The authors also attempted to control for different powders and powder charges used in different commercial loads by firing hand loaded cartridges that had been charged with the same powder.
They then adjusted the hand loads to match the same power factor comparing .45 ACP to .40 S&W and 9 mm Luger to 38 Super.
They found that when the power factor was matched the recoil, as measured by Ransom rest pistol movement was virtually identical for .45 ACP compared to .40 S&W, and for 9mm Luger compared to 38 Super. This makes sense to me since they controlled for pistol weight. Therefore the momentum imparted by the powder charge to the projectile (power factor) would equal the momentum imparted to the pistol which would result in equal movement of the pistol within the rest, given the same pistol weight.
The measured recoil of .45 ACP and .40 S&W was quite similar even when powder charge and power factor were not adjusted for. But as many who shoot both calibers would say, .45 ACP recoil is often perceived as a slower "push" whereas .40 S&W recoil is perceived as a sharper "snap". The authors opined that the faster .40 S&W projectile which dwells in the barrel a shorter time than the .45 ACP projectile, produces a faster recoil impulse. This makes sense to me.
If you have an accurate measure of muzzle velocity, projectile momentum is easy to calculate for any given projectile mass. It is momentum in lb-ft/sec equals projectile mass in grains times muzzle velocity in feet per second divided by 7000. If you compute the projectile momentum for similar 9 mm Luger loads (FMJ from the same maker, for example) for 115, 124, and 147 grain projectiles, you will usually find that the momentum increases by 0.8-1.0 lb-ft/sec as you step up each projectile weight. That would imply that the recoil will increase with increasing projectile mass. But those heavier projectiles also have lower velocity and dwell in the barrel longer, so the velocity imparted to the slide might be less.
For what it is worth I have heard some claim that 115 grain produces more recoil than 124 grain when shot from the same gun, and some the opposite. And I have heard some say the 147 grain shoots softer than 124 grain, and some the opposite.
Bill DeShivs
New member
Of course it has a simple answer.
Heavier.
Heavier.
LineStretcher
New member
A heavier bullet requires more energy to move it.. Because it is harder to move, chamber pressures in all directions also increase. So yes, the heavier the bullet the greater the felt recoil. Simple answer..
NoSecondBest
New member
Doesn't matter what your opinion is about it, the law of physics are set in stone. Newton got it right hundreds of years ago. The simple answer is heavier.
If the light and heavy bullets are both moving at the same velocity, then the heavier bullet would have more muzzle energy, and according to Newton more recoil...all else being equal. Typically, the lighter bullet is moving faster than the heavier bullet because we adjust the powder charge. Since velocity is squared in the equation, that would have much more impact on recoil.
Recoil is made up of 4 things that all are important.
Weight of the projectile
Weight of the powder charge
Weight of the firearm
Velocity of the projectile
If the weight of the projectile goes up and the powder charge and velocity remain the same you get more recoil
BUT.... When you go up in bullet weight in the same cartridge the powder charge will be less and velocity will be less.
It is a complicated issue with no easy answer.
You also have to consider recoil velocity. If 2 guns have exactly the same recoil in ft lbs, it is very common for one of them to recoil FASTER. That will make recoil SEEM like it is hitting you harder than another gun that spreads the same exact recoil out over a longer period of time. Generally heavier bullets recoil slower than lighter, faster bullets.
A 35 Whelen with a 250 gr bullet has almost exactly the same recoil as a 300 WM shooting 180 gr bullets. The 300 uses about 50% more powder and is shooting a lighter bullet about 600 fps faster.
But because of recoil velocity most people find a 35 Whelen more comfortable to shoot.
Plug in the numbers here and stop guessing
http://www.handloads.com/calc/recoil.asp
Weight of the projectile
Weight of the powder charge
Weight of the firearm
Velocity of the projectile
If the weight of the projectile goes up and the powder charge and velocity remain the same you get more recoil
BUT.... When you go up in bullet weight in the same cartridge the powder charge will be less and velocity will be less.
It is a complicated issue with no easy answer.
You also have to consider recoil velocity. If 2 guns have exactly the same recoil in ft lbs, it is very common for one of them to recoil FASTER. That will make recoil SEEM like it is hitting you harder than another gun that spreads the same exact recoil out over a longer period of time. Generally heavier bullets recoil slower than lighter, faster bullets.
Of course it has a simple answer.
Heavier.
A 35 Whelen with a 250 gr bullet has almost exactly the same recoil as a 300 WM shooting 180 gr bullets. The 300 uses about 50% more powder and is shooting a lighter bullet about 600 fps faster.
But because of recoil velocity most people find a 35 Whelen more comfortable to shoot.
Plug in the numbers here and stop guessing
http://www.handloads.com/calc/recoil.asp
Last edited:
Jim Watson
New member
If the OP really means the OQ
"with same 'powder' load, which bullet weight has more recoil? A lighter one or a heavier one? 115gr or 124 gr? 9mm?"
Then the heavier bullet will have the greatest recoil.
For many powders, a maximum load for a 147 is a starting load for a 124 and a powderpuff load for 115 grain bullet. Velocity is not much different so the heavier bullet will have the most momentum.
"with same 'powder' load, which bullet weight has more recoil? A lighter one or a heavier one? 115gr or 124 gr? 9mm?"
Then the heavier bullet will have the greatest recoil.
For many powders, a maximum load for a 147 is a starting load for a 124 and a powderpuff load for 115 grain bullet. Velocity is not much different so the heavier bullet will have the most momentum.
Here's an answer based on data. The question was which produces more recoil when they use the same powder load. The answer depends on what actually happens when bullets of different weights get the same load.
The answer is: generally, the heavier bullet will produce more recoil. Now let's qualify that with data. With handgun rounds, generally, the heavier bullet can actually go faster than the light bullet when they are loaded the same.
The data at this link shows what happens when you load different bullet weights with the same powder charge. See Table 2. http://www.shootingtimes.com/editorial/power-factor-recoil-bullet-weight-gives-edge/99399 It is 45 Auto data but there's no reason to think it's different in the 9mm.
Since the heavier bullet is going faster, or at least around the same speed as lighter bullets, it will produce more recoil.
There are some caveats for this data. The bullets need to be the same shape and seated to the same OAL. If you start changing bullet shape or OAL, the answer might change because both of these can have a significant effect on velocity (and pressure) and these can alter the recoil.
The article at that link explains the effect of bullet weight on recoil when the different weights are loaded to the same power factor, something that other folks have mentioned. I won't bother with that since that was not part of the original question.
The answer is: generally, the heavier bullet will produce more recoil. Now let's qualify that with data. With handgun rounds, generally, the heavier bullet can actually go faster than the light bullet when they are loaded the same.
The data at this link shows what happens when you load different bullet weights with the same powder charge. See Table 2. http://www.shootingtimes.com/editorial/power-factor-recoil-bullet-weight-gives-edge/99399 It is 45 Auto data but there's no reason to think it's different in the 9mm.
Since the heavier bullet is going faster, or at least around the same speed as lighter bullets, it will produce more recoil.
There are some caveats for this data. The bullets need to be the same shape and seated to the same OAL. If you start changing bullet shape or OAL, the answer might change because both of these can have a significant effect on velocity (and pressure) and these can alter the recoil.
The article at that link explains the effect of bullet weight on recoil when the different weights are loaded to the same power factor, something that other folks have mentioned. I won't bother with that since that was not part of the original question.
Here is a somewhat interesting article which attempted to control for barrel length and pistol weight, measuring magnitude of recoil based on the extent of pistol movement when it was fired clamped into a Ransom rest:
http://www.handgunsmag.com/editorial/recoil-comparison-pistol-competition-cartridges/137951#
The authors also attempted to control for different powders and powder charges used in different commercial loads by firing hand loaded cartridges that had been charged with the same powder.
Not sure why you say 'authors' and 'they'. There is only one author.
Last edited:
Aguila Blanca
Staff
Not so simple. Remember, the question stipulates two bullet weights with the same powder charge.LineStretcher said:A heavier bullet requires more energy to move it.. Because it is harder to move, chamber pressures in all directions also increase. So yes, the heavier the bullet the greater the felt recoil. Simple answer..
The fundamental rule of Physics is "For every action there is an equal and opposite reaction." The action in firing a handgun is the rapid combustion of the powder. This combustion generates energy/force. This energy/force acts equally in all directions. Radially, the force is constrained by the surrounding cartridge case and barrel. That leaves two directions in which the energy can act -- forward (pushing the bullet), and rearward (pushing the slide and then the firearm).USNRet93 said:with same 'powder' load, which bullet weight has more recoil? A lighter one or a heavier one? 115gr or 124 gr? 9mm?
In this case, since the powder charge has been stipulated to be the same, what's going to change is how fast the charge can push the bullet. It's axiomatic that for the same powder charge a heavier bullet will result in more felt recoil than a lighter bullet. This appears, at first, to be contradictory. Since the force is acting on a lighter bullet, it would seem that the opposing force (recoil) would also be less. The overlooked factor is that the lighter bullet accelerates faster and exits the barrel sooner. As soon as the bullet leaves the barrel, there's nothing there for the column of expanding gas to push against. From that point forward in time, any gas left in the barrel and chamber basically dissipates without adding anything to bullet velocity or recoil.
The overlooked factor is that the lighter bullet accelerates faster and exits the barrel sooner.
The light bullet generally goes slower than the heavier bullet (see the link in my previous post), so I'm not sure it will exit the barrel sooner.
As soon as the bullet leaves the barrel, there's nothing there for the column of expanding gas to push against. From that point forward in time, any gas left in the barrel and chamber basically dissipates without adding anything to bullet velocity or recoil.
The exiting gas does add to the recoil, in accordance with "for every action there is an opposite and equal reaction" - just like you said. The gas exits at speed, faster than the bullet exits, producing a forward force. This creates a reciprocal backward force. https://en.wikipedia.org/wiki/Recoil#Including_the_ejected_gas
Formulas that calculate recoil require the weight of the powder to be included in the calculation of the recoil force in accordance with the conservation of mass. The powder weight is considered part of the ejecta. e.g. http://kwk.us/recoil.html
And there's this: http://www.shootingtimes.com/editorial/gunpowder-contribution-to-recoil/328788