Powder type and charge vs felt recoil

Recoil is a result of accelerating the bullet and and /powder gas up the bore of the rifle. You can thing of it simple as F=ma where m is the mass of the bullet and the powder at any point in the barrel. That force is exerted on the rifle as well. You can go to SAAMI and find the recoil velocity and energy formula. The rate at which that force is changing is what we perceive as a push or a punch. A punch is what we feel when the acceleration is changing rapidly and a push is a more gradual rate of change in the acceleration. In the physics world this rate of change of acceleration is called "jerk" and no I'm not making that up. Because faster powders generate pressure faster the bullet accelerates faster and for a given bullet will make the recoil feel sharper than a slower powder which builds pressure slower and creates more of a push when giving the same velocity. It is also not unusual for a rifle cartridge to have the powder contribute 30 to 40% of the velocity that creates the recoil energy.

FEENIX said:

All of them as well as reloading manuals, and what SAAMI has in calculating recoil (felt/perceived) are simulations or references and YMMV. If you want an actual measurement, you need a means to measure the actual force/energy generated by a load combination. Ultimate Reloader had a similar set-up when they measure muzzle brake reduction effectiveness. His set-up was not cheap. He also wriote the software program to show what he was trying to measure.

A savvy QL or GRT end-user might be able to do a more informative simulation.

In your example in #1, whichever load combination has the higher energy would probably generate more felt/perceived recoil.

Good luck!

ADDED: This is with 190 Berger VLD out of my .30 Gibbs; same COAL/CBTO.

61g H4831SC, MV=2599 FPS/E=2850 FT-LBS

56g RL-17, MV=2778 FPS/E=3256 FT-LBS

Click to expand...

Rifle weight matters!!!

Assuming this is an ordinary hunting rifle, like a rechambered/re-barreled .30-06 that weighs 8.3 pounds with a nice 4-15X42 scope intended for carry in the woods for shooting deers & elks. Possibly 22-inch #2 barrel, aluminum rings, and a nice 1 inch thick recoil pad.

Or a heavier .30 Gibbs having a 24-inch, #4 barrel weighing 9.8 pounds. Possibly bigger scope & whatever attached to rifle.

Adding 45 fps, for the extra 2 inches of barrel length.

The laws of established science are inexorable. Newton, the real olde physics guy was probably energized to get into this stuff when the falling apple hit him.





The two screen shots are identical except:
The top SS shows the method for calculating rifle velocity (by momentum, P*V, vector) as the rifle is pushed back into the shooter body, like Wt1*V1 + Wt2*V2 / Wt3, Wt3 is weight of rifle in grains, like lbs * 7000 - keeping all units the same. The rifle velocity is calculated using the established physics laws of momentum, P = M * V, a vector having direction and velocity.

The bottom SS shows the method for calculating rifle kinetic energy (applied energy) as the rifle hits the shooters body,like R= 1/2 M*V^2. The velocity of the rifle has been determined, the standard mass calculation is made by division of acceleration of gravity converting pounds into slugs then the kinetic energy of recoil is determined.

Of all the recoil info stuff I looked at I liked the Robinette info best. In his presentation a photo was shown as powder gas out-accelerated the bullet. Robinette provided 1.7 times bullet velocity to get powder gas velocity. I used the 1.7 in my calcuations.

The momentum would be less as powder weight decreases. The powder gas velocity increase over bullet velocity provides an appreciation of various muzzle brakes.

I had a Vais brake on my .375 H&H and at one time when I fired it other nearby shooters thought I had a KABOOM! Muzzle brakes are noisy but work as they reduce the jet effect of raging powder gas acceleration.

Hugnot said:

Rifle weight matters!!!

Assuming this is an ordinary hunting rifle, like a rechambered/re-barreled .30-06 that weighs 8.3 pounds with a nice 4-15X42 scope intended for carry in the woods for shooting deers & elks. Possibly 22-inch #2 barrel, aluminum rings, and a nice 1 inch thick recoil pad.

Or a heavier .30 Gibbs having a 24-inch, #4 barrel weighing 9.8 pounds. Possibly bigger scope & whatever attached to rifle.

Adding 45 fps, for the extra 2 inches of barrel length.

The laws of established science are inexorable. Newton, the real olde physics guy was probably energized to get into this stuff when the falling apple hit him.


View attachment 610479
View attachment 610475

The two screen shots are identical except:
The top SS shows the method for calculating rifle velocity (by momentum, P*V, vector) as the rifle is pushed back into the shooter body, like Wt1*V1 + Wt2*V2 / Wt3, Wt3 is weight of rifle in grains, like lbs * 7000 - keeping all units the same. The rifle velocity is calculated using the established physics laws of momentum, P = M * V, a vector having direction and velocity.

The bottom SS shows the method for calculating rifle kinetic energy (applied energy) as the rifle hits the shooters body,like R= 1/2 M*V^2. The velocity of the rifle has been determined, the standard mass calculation is made by division of acceleration of gravity converting pounds into slugs then the kinetic energy of recoil is determined.

Of all the recoil info stuff I looked at I liked the Robinette info best. In his presentation a photo was shown as powder gas out-accelerated the bullet. Robinette provided 1.7 times bullet velocity to get powder gas velocity. I used the 1.7 in my calcuations.

The momentum would be less as powder weight decreases. The powder gas velocity increase over bullet velocity provides an appreciation of various muzzle brakes.

I had a Vais brake on my .375 H&H and at one time when I fired it other nearby shooters thought I had a KABOOM! Muzzle brakes are noisy but work as they reduce the jet effect of raging powder gas acceleration.

Click to expand...

It's as if you put some thought into this…

I have certainly felt a difference in the vibration to my face by switching powders; even when the bullet velocity was the same in both cases.

FEENIX said:

All of them as well as reloading manuals, and what SAAMI has in calculating recoil (felt/perceived) are simulations or references and YMMV. If you want an actual measurement, you need a means to measure the actual force/energy generated by a load combination. Ultimate Reloader had a similar set-up when they measure muzzle brake reduction effectiveness. His set-up was not cheap. He also wriote the software program to show what he was trying to measure.

A savvy QL or GRT end-user might be able to do a more informative simulation.

In your example in #1, whichever load combination has the higher energy would probably generate more felt/perceived recoil.

Good luck!

ADDED: This is with 190 Berger VLD out of my .30 Gibbs; same COAL/CBTO.

61g H4831SC, MV=2599 FPS/E=2850 FT-LBS

56g RL-17, MV=2778 FPS/E=3256 FT-LBS

Click to expand...

Good point on the energy! I hadnt thought of it that way but it makes sense.

FireFlyFishing said:

I must admit I have never considered this hypothesis mainly because I have not felt any noticeable differences in the cartridges I test and the respective powders for those test loads. Generally speaking, I care about precision of a test load far more than felt recoil. Both in velocity variance and group size. When shooting any rifle that has significant recoil, I reduce the recoil with a lighter bullet, a brake, a suppressor, or a combination of a lighter load and a muzzle device.
So I guess I'll ask...does it matter?

@FEENIX

Click to expand...

NOPE! Hahaha Just somethin fun to think about.
After huntin season Im gunna do a lil test with the appropriate powers I have and see if I can tell anything. Run a one one shot ladder to pressure. Then load 3 and try em. Just for the sake of learnin somethin.

FireFlyFishing said:

One more side note I will add:

This may be a little off target, but I have had test loads that were very spicy and yes, I could physically feel the difference in the recoil of the rifle. Like a substantial increase. These loads were also while using a muzzle device.

So, regardless of powder and projectile used in whatever cartridge, I ensure the final load used chambers without fail and and NO pressure issues regardless of ambient air temperatures. I've found my range finder, ballistics calculator, and reliable scopes will get the projectile on target...albeit a touch slower. Again, accurate and precise loads trump high velocity...for me anyway.

Click to expand...

Absolutely.

std7mag said:

I'll go on record as to different powders giving different recoil impulses with the same bullet.

Shooting 7mm-08AI with the 140gr Berger VLDH for example.

The recoil impulse from RL16 was sharp and harsh!
Way more than RL17, RL15, PP2000MR, H414, IMR4350.

Which seems strange because the PP2000MR is the fastest burning of those choices.

Click to expand...

Interesting! Thanks for sharin that. In certain rifle weights or stock designs that kinda recoil jus feels violent sometimes.

Hugnot said:

Rifle weight matters!!!

Assuming this is an ordinary hunting rifle, like a rechambered/re-barreled .30-06 that weighs 8.3 pounds with a nice 4-15X42 scope intended for carry in the woods for shooting deers & elks. Possibly 22-inch #2 barrel, aluminum rings, and a nice 1 inch thick recoil pad.

Or a heavier .30 Gibbs having a 24-inch, #4 barrel weighing 9.8 pounds. Possibly bigger scope & whatever attached to rifle.

Adding 45 fps, for the extra 2 inches of barrel length.

The laws of established science are inexorable. Newton, the real olde physics guy was probably energized to get into this stuff when the falling apple hit him.


View attachment 610479
View attachment 610475

The two screen shots are identical except:
The top SS shows the method for calculating rifle velocity (by momentum, P*V, vector) as the rifle is pushed back into the shooter body, like Wt1*V1 + Wt2*V2 / Wt3, Wt3 is weight of rifle in grains, like lbs * 7000 - keeping all units the same. The rifle velocity is calculated using the established physics laws of momentum, P = M * V, a vector having direction and velocity.

The bottom SS shows the method for calculating rifle kinetic energy (applied energy) as the rifle hits the shooters body,like R= 1/2 M*V^2. The velocity of the rifle has been determined, the standard mass calculation is made by division of acceleration of gravity converting pounds into slugs then the kinetic energy of recoil is determined.

Of all the recoil info stuff I looked at I liked the Robinette info best. In his presentation a photo was shown as powder gas out-accelerated the bullet. Robinette provided 1.7 times bullet velocity to get powder gas velocity. I used the 1.7 in my calcuations.

The momentum would be less as powder weight decreases. The powder gas velocity increase over bullet velocity provides an appreciation of various muzzle brakes.

I had a Vais brake on my .375 H&H and at one time when I fired it other nearby shooters thought I had a KABOOM! Muzzle brakes are noisy but work as they reduce the jet effect of raging powder gas acceleration.

Click to expand...

I am unsure if you meant to respond to me, but I appreciate the hard work you are showing me. I am also fully aware of how to arrive at those numbers. Cheers!

Doom2 said:

Recoil is a result of accelerating the bullet and and /powder gas up the bore of the rifle. You can thing of it simple as F=ma where m is the mass of the bullet and the powder at any point in the barrel. That force is exerted on the rifle as well. You can go to SAAMI and find the recoil velocity and energy formula. The rate at which that force is changing is what we perceive as a push or a punch. A punch is what we feel when the acceleration is changing rapidly and a push is a more gradual rate of change in the acceleration. In the physics world this rate of change of acceleration is called "jerk" and no I'm not making that up. Because faster powders generate pressure faster the bullet accelerates faster and for a given bullet will make the recoil feel sharper than a slower powder which builds pressure slower and creates more of a push when giving the same velocity. It is also not unusual for a rifle cartridge to have the powder contribute 30 to 40% of the velocity that creates the recoil energy.

Click to expand...

Nice! Thats a good explanation of it

FEENIX said:

If you want an actual measurement, you need a means to measure the actual force/energy generated by a load combination. Ultimate Reloader had a similar set-up when they measure muzzle brake reduction effectiveness. His set-up was not cheap. He also wrote the software program to show what he was trying to measure.

Click to expand...

@Wilderness Blacktail, here are the UL videos I was referring to.

FEENIX said:

@Wilderness Blacktail, here are the UL videos I was referring to.

Click to expand...

Thanks. I'll give them a look.