Gunpowder Selection for Controlling Recoil

[BigDog58]

Thought I'd share this article. If you reload, you might want to read this. It is informative IMHO.

Many competitive shooters load their own ammunition. Handloading allows you to develop accurate, reliable loads custom tailored to your needs. We often select a gunpowder based on its accuracy potential, consistency, cost and cleanliness. There is another factor to consider―recoil.

https://www.ssusa.org/articles/2017/6/19/gunpowder-selection-for-controlling-recoil?fbclid=IwAR3O0qO1cHZLuLCKAWKhnGJR5SA9kMLoT74ZIfPvXJ_Nw4ffzS5JrsDo9Ls

[Ghost]

Makes sense

[gun_fan111v2]

Thanks for posting this. Food for thought.

[crbutler]

I would say that he is overstating the case some. I really doubt his ransom rest criteria is repeatable (it makes a difference how tight you screw the inserts in and how you reset it.

I've noticed a difference in perceived recoil based on powder weight with velocity match only in very extreme conditions.

.470 NE with a velocity of 2150 FPS with a 500 grain bullet.
120 grains of powder vs 90. That was noticeable to guys who shoot guns of that nature regularly. For the inexperienced, they all said "that was bad... not as bad as I expected, but bad." They could not notice the difference between the loads reliably.

The bigger issue is with a larger charge of powder (assuming identical velocity) is more muzzle blast and flash- this is probably more your issue as far as perceived recoil with this situation.

A better point for handgun loads with power factor is that a heavy bullet at a slower velocity making power factor feels very different than a lighter bullet moving faster to make the same power factor. I won't say that recoil is vastly different, but it does feel very different.

[Holland&Holland]

Recoil is a word for wimps, time back on target is a more accurate measure

[GoodDoctor]

"Re: Gunpowder Selection for Controlling Recoil
Postby crbutler on Tue Feb 05, 2019 11:39 pm

I would say that he is overstating the case some. I really doubt his ransom rest criteria is repeatable"

Additionally, in his test on the Ransom rest the author states he used Sierra loading data for the two powders, but he did not use Sierra's gun and he did not verify the powder charges for 1000 fps MV in his gun.

[GoodDoctor]

A better point for handgun loads with power factor is that a heavy bullet at a slower velocity making power factor feels very different than a lighter bullet moving faster to make the same power factor. I won't say that recoil is vastly different, but it does feel very different.

This is a very good point, it raises the question of what is really felt by the shooter. We all know that the bullet is accelerated down the barrel by the powder charge and attains a certain MV, which takes a certain amount of force delivered over a certain amount of time in which to to do this. The shooter feels the same force, as described by Newton's laws, in the recoil. The force comes from the chamber/barrel pressure curve and is proportional to the area under that curve. We also know that the different powders have different burn rates, which means that for any given amount of powder, the pressure curve is going to rise and fall faster or slower depending on the burn rate of the powder. So, lets assume, to accelerate a bullet to a certain velocity takes X amount of total force/energy. But you can vary the degree of acceleration, for instance choosing one powder over another, such that you can get the same force with, lets say, acceleration Y for 1.1 milliseconds, or accelerate at a faster rate Z for 0.8 seconds. Thus, X (proportional to the area under the pressure curve) is equal to either Y for 1.1 millisecond or Z for 0.8 milliseconds. What looks different between the Y and Z pressure curves is the Y curve is going to be taller and narrower compared to the Z curve. The Y impulse recoil is going to hit harder in a shorter period of time than the Z acceleration curve. I don't think anyone holding a firearm can tell the difference in time between 0.8 and 1.1 milliseconds, but they will perceive the difference in the peak impulse pressures, and the faster, higher impulse will feel like more recoil. But in the grand scheme of things, both have the same, net recoil, for the same bullet and muzzle velocity achieved. Power factor determination just takes this up a notch or two because of the bullet weight and velocity changes noted in crbutler's post.

[Ironbear]

But in the grand scheme of things, both have the same, net recoil, for the same bullet and muzzle velocity achieved. Power factor determination just takes this up a notch or two because of the bullet weight and velocity changes noted in crbutler's post.

You missed a piece of it. The powder gets converted into an equivalent mass of hot gasses. The hot gases get ejected as well, and at a higher velocity than the bullet. The momentum change in the gases adds to the recoil impulse and needs to be included as well. The more mass out the barrel, the more impulse for a given velocity. The difference can be measured... the question is can it really be felt?

This is why comp'ed guns run hot loads. They want a lot of gas to trap, stop and redirect; in order to generate recoil reducing impulse.