2ndsojourn
New member
Can someone explain why the 357 recoil is so much more than 9 mm if the saami pressure specs are the same?
http://handloads.com/misc/saami.htm
http://handloads.com/misc/saami.htm
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Pressure vs. recoil
- Thread starter 2ndsojourn
- Start date
g.willikers
New member
Some of the perceived recoil is from the caliber, some from the bullet weight and some from the design of the gun.
Even with the same pressure, there's many other aspects involved.
Even with the same pressure, there's many other aspects involved.
Weight of bullet and velocity have more to do with recoil than pressure does. Think about it, .243 at higher pressure than a 30 06 but kicks much less. The 30 06 with a 110 gr bullet will have much less recoil than the 30 06 with a 200 gr bullet even tho the pressures may be the same.
Recoil is calculated using a mathematical formula with 4 factors. Pressure isn't one of them.
Projectile weight
Projectile speed
Firearm weight
And probably the most important and the one most often overlooked is
Powder charge weight.
Some cartridges are much more efficient at using less powder to achieve equal, or nearly equal speeds. A 357 magnum may need as much as 3X as much powder in order to get just slightly more speed than 9mm. Even if everything is equal 50-100 fps adds recoil far out of proportion. I've seen 3-4% more speed equal 15-20% more recoil on some calculations I've run.
When you combine much larger powder charges, 50-100 fps more speed, and the fact that many 357's are loaded with heavier 158 gr loads vs 125 gr 9mm loads you get the perfect storm of greater recoil.
This is offset somewhat by heavier 357 guns. But the muzzle blast of that much more powder is wicked. The mind will perceive more noise as greater recoil even though it may not be so in reality.
You are on a good website, but the wrong page. Go here and plug in some numbers and it can be educational
http://handloads.com/calc/recoil.asp
Projectile weight
Projectile speed
Firearm weight
And probably the most important and the one most often overlooked is
Powder charge weight.
Some cartridges are much more efficient at using less powder to achieve equal, or nearly equal speeds. A 357 magnum may need as much as 3X as much powder in order to get just slightly more speed than 9mm. Even if everything is equal 50-100 fps adds recoil far out of proportion. I've seen 3-4% more speed equal 15-20% more recoil on some calculations I've run.
When you combine much larger powder charges, 50-100 fps more speed, and the fact that many 357's are loaded with heavier 158 gr loads vs 125 gr 9mm loads you get the perfect storm of greater recoil.
This is offset somewhat by heavier 357 guns. But the muzzle blast of that much more powder is wicked. The mind will perceive more noise as greater recoil even though it may not be so in reality.
You are on a good website, but the wrong page. Go here and plug in some numbers and it can be educational
http://handloads.com/calc/recoil.asp
Limnophile
New member
Recoil is calculated using a mathematical formula with 4 factors. Pressure isn't one of them.
Projectile weight
Projectile speed
Firearm weight
And probably the most important and the one most often overlooked is
Powder charge weight.
Don't forget the speed of the combustion gases. I believe most use a default assumption that combustion gas muzzle velocity is 50% greater than bullet muzzle velocity for handguns.
Good advice to play with a recoil calculator or formula to understand the physics involved.
The calculators and formulas provide free recoil. Felt recoil can seem less. For example, the mechanical nature of a semiauto absorbs some of that energy by putting it to work by, for example, moving the slide, compressing the recoil spring, moving the barrel, cocking the hammer, and feeding the next round. None of that happens in a revolver, so it is almost certain that the same 9 Luger round fired from a pistol and a revolver having the same barrel lengths will "generate" more felt recoil in the revolver.
My blowback-operated .380 has roughly the same felt recoil as my recoil-operated 9 Luger, likely because the blowback action does less work, so more of the recoil energy gets transferred to me.
Pressure has nothing directly to do with recoil. The two elements affecting recoil are the mass and the velocity of the projectile, which includes the gas and unburned powder.
The amount and distance of the recoil depends on the mass of the gun; its mass times its velocity is equal to the mass times velocity of the projectile. Since the gun is a lot heavier than the projectile, of course it moves less and more slowly.
Jim
The amount and distance of the recoil depends on the mass of the gun; its mass times its velocity is equal to the mass times velocity of the projectile. Since the gun is a lot heavier than the projectile, of course it moves less and more slowly.
Jim
For just math calculations, the listed factors matter. FELT recoil is different, and several other factors ALSO have significance.
The "platform" matters. The .357 Mag and the 9mm Luger are not the same round, despite having the same working pressure in SAAMI specs.
Most of the difference in felt recoil is due to the different guns used to fire the rounds. Semi auto vs DA or SA revolver.
The rest of the difference is the rounds themselves. Generally speaking the .357 Mag uses heavier bullets at higher velocities than the 9mm Luger.
Ask one of the guys who has a Ruger Blackhawk .357/9mm convertible what the difference in recoil is like. Same gun, you just change the cylinder. 9mm recoil is less, or so I've heard.
I have the other gun where an equal comparison can be made. I have a Contender with both a 9mm and a .357 Mag barrel (same length 6"). In that gun, 9mm is DEFINATELY less felt recoil.
Comparing the typical semi auto to DA revolver involves many factors that obscure the actual difference between the two rounds.
The "platform" matters. The .357 Mag and the 9mm Luger are not the same round, despite having the same working pressure in SAAMI specs.
Most of the difference in felt recoil is due to the different guns used to fire the rounds. Semi auto vs DA or SA revolver.
The rest of the difference is the rounds themselves. Generally speaking the .357 Mag uses heavier bullets at higher velocities than the 9mm Luger.
Ask one of the guys who has a Ruger Blackhawk .357/9mm convertible what the difference in recoil is like. Same gun, you just change the cylinder. 9mm recoil is less, or so I've heard.
I have the other gun where an equal comparison can be made. I have a Contender with both a 9mm and a .357 Mag barrel (same length 6"). In that gun, 9mm is DEFINATELY less felt recoil.
Comparing the typical semi auto to DA revolver involves many factors that obscure the actual difference between the two rounds.
Independent George
New member
My best guess: .357 pressure is lower due to a longer case and therefore larger chamber. If you've got equal pressure in a larger area, that means the charge is more energetic to begin with.
2ndsojourn
New member
From jmr:
"Recoil is calculated using a mathematical formula with 4 factors. Pressure isn't one of them.
Projectile weight
Projectile speed
Firearm weight
And probably the most important and the one most often overlooked is
Powder charge weight."
Thanks for your response. I understand the first three, but didn't get the fourth. I don't reload, and don't know the first thing about it, so the referenced reloading calculator didn't help me at all. And I fully understand the difference made by the bullet weight and the weight of the gun. But I thought with the pressure being equal and the bullet weight being equal (or close), that the recoil would be about the same.
From 44:
"Ask one of the guys who has a Ruger Blackhawk .357/9mm convertible what the difference in recoil is like. Same gun, you just change the cylinder. 9mm recoil is less, or so I've heard."
I have one of those and was shooting it a couple weeks ago. I don't know the bullet weight of the loose 357 cartridges I was shooting but the 9 mm was 124 gr Speer. The recoil was noticeably different. Hence the question.
....................
It seems most of the answer lies in the powder burn rate and the amount of powder. Thanks for your explanation.
"Recoil is calculated using a mathematical formula with 4 factors. Pressure isn't one of them.
Projectile weight
Projectile speed
Firearm weight
And probably the most important and the one most often overlooked is
Powder charge weight."
Thanks for your response. I understand the first three, but didn't get the fourth. I don't reload, and don't know the first thing about it, so the referenced reloading calculator didn't help me at all. And I fully understand the difference made by the bullet weight and the weight of the gun. But I thought with the pressure being equal and the bullet weight being equal (or close), that the recoil would be about the same.
From 44:
"Ask one of the guys who has a Ruger Blackhawk .357/9mm convertible what the difference in recoil is like. Same gun, you just change the cylinder. 9mm recoil is less, or so I've heard."
I have one of those and was shooting it a couple weeks ago. I don't know the bullet weight of the loose 357 cartridges I was shooting but the 9 mm was 124 gr Speer. The recoil was noticeably different. Hence the question.
....................
It seems most of the answer lies in the powder burn rate and the amount of powder. Thanks for your explanation.
Pressure isn't the best factor to use. The problem is that the figure given for pressure is the maximum pressure limit for the brass. It doesn't tell you anything about the volume or duration of the pressure impulse.
Recoil is basically momentum, which is basically bullet mass x velocity.
The .357 magnum typically fires a heavier bullet faster than a 9mm, so that's why recoil tends to be much higher. If you handloaded a .357 mag with the same bullet weight and velocity as a 9mm, it would have nearly identical recoil.
Recoil is basically momentum, which is basically bullet mass x velocity.
The .357 magnum typically fires a heavier bullet faster than a 9mm, so that's why recoil tends to be much higher. If you handloaded a .357 mag with the same bullet weight and velocity as a 9mm, it would have nearly identical recoil.