How does powder burn rate effect recoil

[ckc123]

I had the chrony out this weekend, and I was using WWB as a "base" to see the accuracy of the chrony.

One thing I did notice.. the WWB (.40 180 grain) had a lot more felt recoil, then the loads I was using (both where 990 fps, and 180 grain).

I'm using Titegroup which is a fast powder (I'm assuming it faster then the unlisted powder winchester uses)..

Is it a fair assumption that the difference was due to the slower powder in the WWB?

(there was also a OAL differnce of 1.125 for WWB and 1.2 for my reloads)

 

[the rifleman]

Recoil as per ft/lbs to your shoulder is only determined by the weight of the gun, weight of the bullet, and the velocity.

"Percieved" recoil, does vary with powder, as to the spike. Slow burning powders seem to give a push, rather than a kick as faster powders may.

 

[mrefaat]

it is not the burn rate, but it is the velocity of powder gases that has an impact on recoil.
I = (Wb*Vb + Wc*Vc)/225400 I = recoil impulse, lb.-sec.Wb = bullet weight, grainsVb = muzzle velocity of bullet, f.p.s.Wc = weight of powder charge, grainsVc = velocity of powder gases, f.p.s. 225400 = unit correction factor (7000 gr./lb.*32.2 f.p.s.2)

I tested Bullseye to determine the Wc, and it was ~2000FPS.

now once this is done, you can calculate the Recoil energy:
E = Wg*(Vg)2/64.4Where: E = free-recoil energy, ft.-lbs.Mg = mass of the gun (Wg/32.2)Wg = weight of gun, lb.64.4 = acceleration of gravity*2, f.p.s.2Vg = free-recoil velocity of the gun, f.p.s

here is another way to calculate the Recoil Energy:
E = 1/2 (Wg / 32) (Wb x MV + 4700 x Wp / 7000 x Wg)squared
Where E = recoil Energy in ft. lbs.,
Wg = Weight of gun in pounds,
Wb = Weight of bullet in grains,
M = Muzzle, V = Velocity in feet-per-second,
Wp = Weight of powder in grains

 

[Andy]

The amount (weight) of the powder also factors into the recoil equation, so for a given muzzle velocity, the slower powder will yield more recoil.

 

[ckc123]

here is another way to calculate the Recoil Energy:
E = 1/2 (Wg / 32) (Wb x MV + 4700 x Wp / 7000 x Wg)squared
Where E = recoil Energy in ft. lbs.,
Wg = Weight of gun in pounds,
Wb = Weight of bullet in grains,
M = Muzzle, V = Velocity in feet-per-second,
Wp = Weight of powder in grains

Unfortunatly I didn't keep any rounds left from the WWB, but in theory..
if I measure the power differences between the WWB and my load (4.8 grains) I should be able to come up with a "recoil factor between the two rounds.. (as they are the same FPS, and the same gun, and the same weight)

 

[Boomer]

Rather than a long winded explanation I'll just show you the data I took from my recoil calculator.

.375 H&H
rifle weight - 8 pounds
bullet weight 300 grs
velocity -2440 fps
67.0 grs IMR-4064 = 43.7 ft/lbs of recoil
82.0 grs H-4831 = 49.8 ft/lbs of recoil

From this data we may conclude that when more powder is loaded to a cartridge, as is the case if we match the velocity of a particular bullet obtained with a fast burning powder when using a slow burning powder, recoil increases.

 

[Andy]

Look back three posts for the same conclusion...... Hard to find amongst all the gobbledegook.

 

[Dragoon]

Rule of thum for non-compensated pistols, the least 'perceived' recoil is achieved by combining the fastest powder with the heaviest bullet. For compensated handguns the opposite is true. (light bullet - slow powder)

 

[Keebler750]

Force = Mass x Acceleration

Force is felt recoil. Mass is the bullet and firearm weight. Acceleration is a RATE of change.

Powder burn rate affects how quickly the chamber pressure is achieved. The quicker the burn rate, the quicker the bullets acceleration....even if it ends up at the same speed.

Faster burn rates, all else being equal, will feel like a 'sharper' recoil.....because it IS!!!!

If you accelerate your car slowly to 30mph, you barely feel it. If you accelerate QUICKLY to 30mph, your head snaps back!

 

[Keebler750]

...
From this data we may conclude that when more powder is loaded to a cartridge, as is the case if we match the velocity of a particular bullet obtained with a fast burning powder when using a slow burning powder, recoil increases.

To get a slower burning powder to achieve the same velocity, we have to have a higher chamber pressure, ie. more of the slower powder to expend the same total energy behind the bullet before it leaves the barrel. So, we really have two questions here....

How does burn rate effect recoil?

How does chamber pressure effect recoil?

The rise in chamber pressure is ultimately what causes both the propulsion of the bullet AND the felt recoil, so it can be said that

"faster burn rates increase chamber pressures quicker, which leads to a proportionate felt recoil in conjunction with a given mass."

 

[Boomer]

To get a slower burning powder to achieve the same velocity, we have to have a higher chamber pressure, ie. more of the slower powder to expend the same total energy behind the bullet before it leaves the barrel. So, we really have two questions here....

How does burn rate effect recoil?

How does chamber pressure effect recoil?

The rise in chamber pressure is ultimately what causes both the propulsion of the bullet AND the felt recoil, so it can be said that

Your assumption is not quite correct. It takes more slow burning powder to achieve a given velocity reached with a faster burning powder, because the slower burning powder has less energy stored in it. The greater mass of powder creates a greater volume of gas energy over a longer period of time. This results in less pressure, but pressure for a longer duration.

If we consider the 180 gr., .30-06 data in the Lyman Manual, we see that the fastest powder listed is IMR 3031 and the slowest is R-22. 46.0 grs of 3031 results in 48,000 CUP while 60.8 grs of R-22 results in 48,400 CUP, yet the R-22 load produces 100 fps more velocity.

If we take this to extremes, and load our cartridge with a high explosive with a VOD (velocity of detonation) of 20,000 fps, there would be no recoil at all, and the rifle would simply break up under the enormous gas energy - assuming we could eliminate the initial shock energy, the presence of which separates high explosives from low explosives. Smokeless propellants are much slower, around 4000 fps, and are, as a result, useful in firearms. So as we see, fast energy release - low recoil, slow energy release - high recoil.