Perceived Recoil and Powder Burn Rate

[bgavin]

As an excuse to avoid doing yard work, I started digging into the idea about how perceived recoil relates to powder burn rate.

I went back through a good number of archived posts about various powders.

The general consensus is a faster powder has a "sharper" recoil characteristic.
• Titegroup (15)
• Clay Dot (11)
• Clays (9)
• Red Dot (7)

Slower powders are thought to have more of a "shove" rather than a sharp bark.
• Unique (32)
• N32C Tin Star (30)
• 231 (29)
• No. 2 (27)
• Trail Boss (23)

To further avoid yard work, I ran these through Quickload to see the total burn percentage in a 5.5" barrel and 38SP.
The intent was avoiding the big fireball from incomplete powder burn.
• H110 (63)
• W296 (64)
• I4427 (65)

Thoughts?

[Wallaby Jack, SASS #44062]

          ....... do the yard work,   ........

 

 

                                           ....... and you might not have to sleep on the couch ......

 

 

[Larsen E. Pettifogger, SASS #32933]

Basic physics.  A 200 grain bullet with a muzzle velocity of 1000 fps is going to have the same recoil regardless of the powder.  A lot of people try loads and think "this one recoils less."  However, in most cases they have not chronographed the loads, only used the published data to guess what the velocity is.  Sort of the placebo effect.  If you "perceive" the recoil as being less, it is.

 

Go do your yard work.  A more productive enterprise.

[bgavin]

No, sorry.
The rate of acceleration is also part of the equation.
The muzzle velocity is only the end product of the acceleration.

I am not asking about which feels like less recoil.
As you note above, the equation of mass and velocity is constant at the muzzle for a given load.
The RATE of acceleration is different.

The fast powders are nearly all done at first ignition.
The slow powders continue to burn longer.
It is also known that slow powders produce less total chamber pressure but greater velocities.

A large number of shooters have characterized the recoil as sharp vs a shove.
I'm looking for well thought out answers.

[bgavin]

48 minutes ago, Wallaby Jack, SASS #44062 said:

 ....... and you might not have to sleep on the couch ......

Maybe in your house, but never in mine.
When I'm on the couch, it is a courtesy to my bride and her health.
Not for punishment.  That crap won't be tolerated.

[Larsen E. Pettifogger, SASS #32933]

6 minutes ago, bgavin said:

I'm looking for well thought out answers.

 

Sorry to have wasted your time.

[Tex Jones, SASS 2263]

Hell, I haven't seen my yard since December.  Maybe by the end of March if the temps get above freezing. 

[Creeker, SASS #43022]

Probably not a well thought out answer - but I think you laid your finger on the crux of the debate.

Acceleration.

And length of that acceleration curve.

 

I'm just making up numbers here - don't take anything as researched...

If powder A goes 0 to 1050 fps within 3 inches and then slows to 1000 fps exiting the 5 inch barrel.  This results in a 1000 fps at the muzzle.

If powder B goes 0 to 1000fps at the 5 inch mark.  This results in 1000fps at the muzzle - same "result" but I assume they would have markedly different feels.

 

And this is of course, without the added considerations of:

Severity of the case crimp

Bullet fitment to forcing cone/ barrel diameter.

Firearm weight

Grip design

etc. and etc.

 

[Cholla]

I look at it this way:

A 1967 Chevelle with a 400 small block can go from 0-60 in seven seconds.

A 1978 Chevy Chevette with warped heads can go from 0-60 in 200 seconds.

One is going to push me back my seat as I feel the G-forces while I am not going to feel anything but shame in the other.

[bgavin]

A car analogy is valid.

Given the quarter mile.
The Chevelle gets up to 60 in seconds, and maintains 60 at the end of the strip.
An Econoline van with a 144 six gets up to 60 by the end of the same quarter mile (the muzzle)
Both vehicles weigh the same.

The recoil calculation will show the mass x velocity as identical at the end of the quarter mile.
The perceived recoil from the RATE of acceleration will be far sharper with the Chevelle than the gutless smoosh of the Econoline van.

[Dusty Devil Dale]

1 hour ago, Wallaby Jack, SASS #44062 said:

          ....... do the yard work,   ........

 

 

                                           ....... and you might not have to sleep on the couch ......

 

 

To a wife, making the husband sleep on the couch is a punishment.  To the husband, it's just a fun camping trip.  

[bgavin]

Good grief... what a terrible marriage that must be.
I've had two of those... both long gone now.

[Tex Jones, SASS 2263]

9 minutes ago, Cholla said:

I look at it this way:

A 1967 Chevelle with a 400 small block can go from 0-60 in seven seconds.

A 1978 Chevy Chevette with warped heads can go from 0-60 in 200 seconds.

One is going to push me back my seat as I feel the G-forces while I am not going to feel anything but shame in the other.

The same as the difference between flying in an Air France Concorde vs a British Airways Concorde.

[Rex M Rugers #6621]

What kind of powder is I4427 ?

Nothing to do with recoil , just curious.

Rex 

[bgavin]

IMR 4227

[Tom Bullweed]

'Powder does not matter' is algebra.

'Powder matters' is calculus.

it makes some sense that the burn rate will impact the force curve, making a slower powder draw out the recoil forces, making the recoil seem less focused.

[Still hand Bill]

This has been done and tested for shotshells.  Makes no measurable difference.  There was a guy Neil Winston who tested all sorts of myths about shotshells using scientific tests.  He has published some of the data, but unfortunately he has since passed away.  He even did double blind tests with shooters and they could not accurately tell the difference between fast or slow powders.  The problem with the hypothesis that slower is more spread out is that the time we are discussing is less than .5 milliseconds.  Far faster than the human body can react.  
 

other variables such as amount of powder (slower tends to have more) effect recoil so a slower powder tends to have more recoil.  Also the jet effect when the projectile leaves the barrel has an effect.  So many things that are different, it’s hard to compare exact loads with only the powder burn speed being different.  

[watab kid]

8 hours ago, Dusty Devil Dale said:

To a wife, making the husband sleep on the couch is a punishment.  To the husband, it's just a fun camping trip.  

i think i can relate to that these days , she kicks in her sleep , 

[Widder, SASS #59054]

Howdy bgavin.

 

There are other variables that can and do effect burn percentages, such as:

 

1. temperatures

2. primer (standard or magnum)

3. and don't forget how hard you pull the trigger... 

 

..........Widder

 

[Eyesa Horg]

That's why you should squeeze the trigger, not just yank it!

[bgavin]

It is valid to load a 45 colt with either Clays or Unique with a 250 gr. LRNFP to 751 fps, and stay within the published load limits.
The recoil calculations return the same result, due to the identical mass and velocity at the muzzle.

However, the burn pattern is very different.
Clays produces a far higher max chamber pressure, and a much faster burn and decay rate.
The rate of acceleration of the bullet in the barrel is faster with Clays.
This is a stronger impulse spread over a shorter period.

Reading the comments from the experienced shooters here, I see a trend in the comments.
The clays and titegroup has more of a "bark" where Unique has more of a "shove".

My thoughts are entirely about the character of the recoil, not the burning characteristics.
 

[Buckshot Bob]

If you use the slowest and fastest burning powders for a given cartridge , and they both get the same weight projectile up to 800fps out of say  5” barrel , I’m going to say that the difference in acceleration Is going to be imperceptible to almost everyone except those of us with Jedi like reflexes 

[bgavin]

Then why do the experienced shooters comment about a sharp bark vs a smooth push?

[Cholla]

Expectations? Not equal loadings? Who knows? I have a relative that swears a bolt action shotgun he uses hits harder than his pump. The shells are the same. There aren't any gases being used for cycling the action. Barring a weight difference of the firearm absorbing the energy, how can they be different? Perhaps the length of pull is different and placing the gun in a different relation on his shoulder? I don't see how but he swears it hits harder. 

I used to have a TC Hawken. Folks told me how the recoil of a BP gun was softer and more of a push. I weighed 140 at the time and it didn't feel like a gentle push to me! I backed off to 50 grains and then it became fun to shoot.

[Happy Jack, SASS #20451]

bgavin,  I also use Quickload a lot. More things you need to add to your data is the  efficiency and % burned at the muzzle. I don''t care enough to do it myself but since you already have the data entered I suspect there will be differences.

[bgavin]

Thanks.
I'm only interested in the recoil impulse of two different powders delivering the same mass and velocity at the muzzle.
I've seen experienced shooters comment about the felt difference between Titegroup and Unique.
I'm trying to understand if this relates to burn rate, which I think it does.

[Buckshot Bob]

45 minutes ago, bgavin said:

Then why do the experienced shooters comment about a sharp bark vs a smooth push?

Either they have Jedi like reflexes , or the placebo effect. Target shooters are crazy? Maybe  it’s the sound . You gotta admit in something like a 4 3/4 SAA the difference in acceleration has to be almost unmeasurable. Especially when you look at the standard deviation in the same load in many guns . When shooting a string If one of people who believe in this phenomenon has a couple of rounds that are 25 or 50 fps slower do they notice the reduced recoil ? I don’t doubt there is a difference but I highly doubt most people could differentiate in a blind taste test 

[Marshal Mo Hare, SASS #45984]

19 hours ago, Dusty Devil Dale said:

To a wife, making the husband sleep on the couch is a punishment.  To the husband, it's just a fun camping trip.  

The dog house would be a camping trip.

[Widder, SASS #59054]

36 minutes ago, bgavin said:

Then why do the experienced shooters comment about a sharp bark vs a smooth push?

 

bgavin,

 

I only have my own belief (theory) to your question, which doesn't make my answer a correct answer.

 

I shoot relatively a lot of ammo, especially some big bore pistols, like the .460 Rowland and a few 10mm pistols.

And I got a couple Ruger .45 SBH Hunters, 5.5" and 7.5" revolvers and short barreled .44 mag S&W (2.75").

 

I have done some good chronograph testing with these big bore revolvers/pistols.  It seems  that some powders

seem to have a sharp 'bark' while other powders seem to have a 'BOOM' sound.

 

The BARK appears to have a greater recoil effect at first, but after shooting enough different loads, etc..... it is my belief

that the SOUND gives the shooter a false pretense that recoil is greater or milder depending upon the BARK or BOOM.

 

In handling, watching, and chronographing various loads thru the years,  recoil perception is sometimes based on SOUND,

not actual movement of the gun.

 

Two powders that I use, that give me identical results in some guns, is LilGun and H110.  And in some loads, I also compare

AA #9.    To ME, the AA9 seems to give me a sharper 'bark' sound while LilGun gives me more of a 'Boom' sound, and less perceived

recoil in the LilGun.   BUT... LilGun seems to give me better performance levels in the big guns with a perceived softer recoil results. 

 

Sometimes, the shaking of the ground makes us weary of how big and powerful the train might be.

Sometimes, its that blame HORN that scares the crap out of us and makes us back away from the tracks.

 

..........Widder

 

[Colorado Coffinmaker]

 

Actually the oft quoted reference to "sharp Bark" actually relates to the perceived sound of the Report.  Not Recoil.  I don't necessarily buy into your differentiation between "perceived" and "felt" recoil.  Basically, without a laboratory accelerometer, and a lab measured amount of impact . . . . your perceptions are basically ALL WET.

 

Recoil is simple physics and is the result of the weight of the projectile regardless of how it's accelerated.  Now, how that recoil is spread over the time stamp may well be perceived, but have no relevance.

 

[bgavin]

I ask an honest question, and get an insult.
All wet.
Thanks.

How about you actually READ my question.
I made NO assertions, just asking a question about what I've seen written by others.

[Lefty Beau Legg, SASS #40745]

"The recoil calculations return the same result, due to the identical mass and velocity at the muzzle"

 

The listed powder weights are different, so I would expect the calculated free recoil energy to be different. SAAMI provides a formula for calculating free recoil energy, and it requires both the bullet and powder weights, in addition to the bullet MV and gun weight. The formula makes an assumption (based on empirical studies) about the effect velocity of the powder gas.

[bgavin]

Yes, the SAAMI calculation does include the weight of the ejecta...
A few grains of powder compared to 250 grains of bullet and a 2.81 pound revolver is inconsequential.

All the above satisfies my curiosity.
 

[Jailhouse Jim, SASS #13104]

I attended a few handgun classes where I used a .40 S&W @800rds/day.  I used Bullseye in one class and Unique in the other.  Standard 180gr pill, velocity was within 50'/s on both loads.  The classes were about 3 months apart.

 

After the Bullseye class, my wrists hurt so I loaded Unique for the second class.  While fatigued at the end of the class as normal, my wrists did not hurt.  

 

I also noticed more muzzle flip with the Bullseye loads hence my Unique loads were fractionally faster on the follow up shots.  The actual recoil seemed similar but the report was sharper with Bullseye.  It was the end of the day results that convinced me Unique was better for competition and high round count days.

[Wallaby Jack, SASS #44062]

2 hours ago, Marshal Mo Hare, SASS #45984 said:

The dog house would be a camping trip.

 

 ....... I think it'd be more of a sleepover at a friends house ......