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Is the degree of recoil perceived?

4K views 40 replies 13 participants last post by  bruce272 
#1 ·
Earlier I posted a comment re: Corbon Ammo. Well I bought a box and finally got a chance to shoot it yesterday. (I'll give you the specs at the end).

I also tried (for the first time) Federal's American Eagle and to me, it felt like the recoil of the American Eagle was more pronounced.

I found this kind of weird, as I set myself up to expect a much greater recoil (this was mentioned by other forum members) from the Corbon.

Am I loosing it ? or has anyone else experienced this (hotter ammo=less felt recoil vs. a load with less velocity and bullet weight=more felt recoil.

Pistol used: 5" 1911 customized with 18 lb. Wolfe recoil spring and buffer.

Corbon Ammo: 230gr +p JHP Velocity 950fps, Energy 461 ft/lbs

American Eagle: 230gr FMJ Velocity 890fps, Energy 405 ft/lbs.

This experienced has totally stumped me. I felt that neither rounds' recoil to be unpleasant although I would assume that the Corbon would have more "kick".

Bruce
 
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#2 ·
no explanation here. Same weight bullet, and the Corbon is faster.

If I had to throw out a wild guess I would say the recoil spring is buffering one more then the other. Slamming back harder on the America, or the Corbon is just more "in tune" with the springs in the gun. Just a wild guess though.
 
#3 ·
If you have to 'guess' on the effectiveness or powe of one type of ammo over another...who cares.
I only worry about what works in my firearm...that's all that counts.
If my gun likes it, then I like it.:yup::comeandgetsome:
 
#5 ·
Nope,

Used the published specs right off the box, could it be that FMJ seals tighter than JHP, thereby causing a greater felt recoil?

Thanks for the responses, please keep them coming.

Bruce
 
#6 ·
I will take a guess. It is the powder burn rate (the speed at which the powder burns). Powders that burn slower produce more felt or preceived recoil because the slower burn rate is still building pressure as the bullet goes down your barrel. A faster burning powder gets the bullet to top speed before it leaves the cartridge and gives you less preceived recoil. The bullet or shot weight may be the same and the bullet speeds may be the same.
 
#8 ·
Sig,

Thanks for the link, interesting reading.

As both these two loads were only fired for the first time, I don't think that "bullet pushback" is the cause. I did find the bit about not shooting +P kinda weird. I guess if you have an alloy pistol that would be something to be aware of, or any ammo in excess as I've seen Commander frame cracks happen.

My 1911 is steel and I doubt that an occasional diet of +P won't be a problem.

Thanks again for the link and let me know if you fall across any other info.

Bruce
 
#9 ·
One way to look at it is, consider the pistol to be a hand held rocket.

When the powder is ignited the pressure builds and propels the bullet down the barrel. Pressure in the thousands of PSI is now contained in the barrel and prevented from escaping by the bullet.

Once the bullet exits the barrel the cork has been popped and all that tremendous pressure must now escape. It does so from the open end of the barrel just like through the nozzle in a rocket.

This force is directed opposite to the escape point and that is (except in ported barrels) straight back. Just like blowing the plug from a CO2 cartridge and watching it take off.

There are more factors to recoil or percieved recoil than that but it is the major force being exerted once a bullet leaves the barrel.

OMO

bosco
 
#10 ·
One way to look at it is, consider the pistol to be a hand held rocket.

When the powder is ignited the pressure builds and propels the bullet down the barrel. Pressure in the thousands of PSI is now contained in the barrel and prevented from escaping by the bullet.

Once the bullet exits the barrel the cork has been popped and all that tremendous pressure must now escape. It does so from the open end of the barrel just like through the nozzle in a rocket.

This force is directed opposite to the escape point and that is (except in ported barrels) straight back. Just like blowing the plug from a CO2 cartridge and watching it take off.

There are more factors to recoil or perceived recoil than that but it is the major force being exerted once a bullet leaves the barrel.

OMO

bosco
I liked your analogy. I will add more to this but what you said is almost exactly what I know to be true. Very well stated.

SIG
 
#11 · (Edited)
Your analogy is dead on but the burn rate of the powder is what creates the pressure. There are two types of powders, one is a single base or nitrocellulose powder, and the other is a double base or nitrocellulose and nitroglycerine base.
The single base powders burn very quickly and expend all the energy within the cartridge or hull. These powders are mainly used in lighter recoil loads with lighter payloads. The double base powders are slow burning and continue to burn and create pressure as the bullet or shot travels down the barrel. Double base powders are mainly used for heavier payloads and hunting loads.
An analogy of the two is like a gasoline engine and a diesel engine. Gasoline is like single base powders, easy to ignite and gets moving quickly. Diesel is like the double base, harder to ignite but creates much more power to pull heavier loads or push as with bullets.
The slower the powder burns the greater the time push back is felt or percieved. Different burn rates and amount of powder used in a load is what we percieve as recoil.
I will add an example for a load from Alliant Powders.
.40 S&W shooting a 180 gr. JHP.
using Unique powder the bullet is traveing 1065 fps. and creating 33,800 psi in the barrel.
Using Blue Dot powder the bullet is traveling 1065 fps but is creating 34,000 psi in the barrel.
Both powders are double base, but Blue Dot is a much slower burning powder and creates more pressure.
On the Relative Burnrate Chart for powders from quickest to slowest, Unique is #25 and Blue Dot is #40.
 
#12 · (Edited)
True...

Amount of powder
type of powder
bullet weight
burn rate
primer flame size
crimp
volume of powder in case
powder compression
distance of seated bullet to where it actually enters the barrel
ambient temperature.

All the above are among the factors that determine how much pressure is built up before the bullet (cork) pops and the rocket effect begins.

Add muzzle brakes, porting, recoil operated actions, gas operated weapons, barrel weight, total weapon weight, barrel axis, type of stocks or grips, caliber at the rocket's nozzle (crown) and total volume of the pressure container (barrel interior volume just prior to bullet exit) into the equation and recoil can get real complicated. LOL

Add to the above the differences each shooter's own ability to tolerate recoil and the only way to determine a gun's or a cartridge's felt recoil is by getting out there and shooting it.

bosco
 
#13 ·
There's also the human factor. If you expected more recoil, you likely braced a hint better. Even at a subconscious level, you likely did it.

But the Rocket analogy with burn rate as the cause, are potentially the greatest impact on what you report, in my opinion.
 
#14 ·
To answer your question more Bruce. Federal uses more medium to slow burn rate powders because they load for everyone. They load ammo for any type of action and gun, and for any type of shooting. I personally have found Federal ammo to have more recoil overall. They sale ammo at a lower price overall as well, but you get what you pay for. Speed of the bullet does not always mean more recoil, it is just another variable.
 
#15 ·
Forget the "perceived" bit about recoil for a moment.

A specific round (say the Amer Eagle 230) produces the same recoil in every/I] gun. It's a matter of physics (X amt of y-type powder behind the 230 grn bullet). Different guns have different weights and different recoil springs, That's what gives the shooter the different "felt" recoil.

The AE 230 will feel like it kicks harder in a 27 oz Glock than the much heavier Govt 1911. The actual energy produced in the cartridge is the same. Just as in a featherweight rifle in a .338 magnum will reset your dentures while the heavier bull-barrel target rifle will absorb most of the kick. But the .338 Mag energy doesn't change.

Does the AE round recoil harder than the Corbon? Quite possibly. Faster powder versus slower powder, etc. There's no "perceived" about it if they're both fired in the same weapon; one kicks more than the other.
 
#16 ·
Noise is also perceived as "recoil."
More muzzle pressure, more noise. More muzzle pressure also makes that rocket thrust.

Shoot with and without hearing protection, the same load [your hearing will suffer possible permanent damage, so I'm not actually suggesting you do it].
 
#17 ·
As the OP stated originally. Two bullets shot from the SAME gun, bullet weights are the SAME. Why does the Federal bullet that is going 60 fps slower, feel like it has more recoil? He has eliminated other variables in his statement. The only variables left are powder burn rate, primer, and amount of powder. Powder burn rate and the type of primer is what creates the barrel pressure. Slower burning powders and hotter primers can create more barrel pressure but still give you slower bullet speeds with more felt recoil and sound.
 
#18 ·
Slower burning powders and hotter primers can create more barrel pressure but still give you slower bullet speeds with more felt recoil and sound.
First, thanks to all of you who responded. It does prove that this old dog can learn new tricks. And I thought I knew it all (yeah, sure).

Trapper,
What I still can't wrap my head around is the fact that more pressure and slower bullet speed (I assume that's measured at the muzzle)equates to more "real" recoil. This seems to be the opposite of everything I've know or been taught.

My old head needs a further explanation of this "reverse physics"

Again,

Thanks to all

Bruce
 
#19 ·
The pressure and the amount (volume) of gas that is released once the bullet exits the barrel (pops the cork) give the rocket effect or force of the recoil.

Same gun with two different bullet weights will exert the same rocket effect as long as the pressure at the time the bullet exits the barrel is the same. Different burn rates and types of powders will give different pressures depending on other variables.

Altering the way in which this force is directed or absorbed (porting, muzzle brakes, gas operation, recoil springs, etc.) will affect the recoil..

OMO

bosco
 
#20 ·
Add to what Bosco has said. A faster burning powder will get the bullet to speed as it leaves the cartridge ( because all the powder has already burned in the cartridge before the bullet moves) and the pressure will disipate as the bullet goes down the barrel. This is because of the room opening up as the bullet moves allowing the pressure to fill this void. A slower burning powder continues to build pressure even as the bullet moves down the barrel and gains speed until the cork pops. The faster burning powder is loosing pressure when the cork pops but the bullet is already at speed. It is a bit confusing to explain but this is as simple as I can get.
 
#21 ·
OK, I think this make alot of sense. The faster powder gets the bullet "up to speed" while still in further in the barrel. Then the pressure inside the barrel drops behind the bullet as the combustion chamber increases in volume (bullet travels down barrel). The slow burn powder continues to increase in pressure until the bullet exits barrel.

However I still have a little trouble with the comment about shooter not feeling ANY recoil until the bullet leaves the barrel. It seems to me that as soon as the primer ignites the cartridge is going to press backwards with the same force as the bullet is propelled forward. See Mr. Newtons third law. "Equal and opposite" if the bullet is moving forward the cartridge is attempting to move backward now, not when the bullet exits the barrel.
 
#22 ·
The pressure on the walls of the barrel, the bullet and the breech are equal as long as the system remains sealed (still plugged by the bullet). Once the bullet leaves the pressure is released. If there is no other way for the pressure to escape (ported barrel, muzzle brake...etc,) it exits out the crown of the barrel, pushing back.

bosco
 
#25 ·
OK, lets look at it from this angle. Lets compare an internal combustion engine and a gun. The piston equals the bullet, both perform work. the cylinder equals the barrel, they both contain the pressure and the bullet/piston travels in them. The connecting rod equals your hand, they both feel the effect of the force created.
So in your argument, you claim that until the bullet leaves the barrel, or the piston flies out of the cylinder, there is no recoil or force on the connecting rod. Then how did you get to work today?

In my example the explosion causes the bullet to move out of the barrel/piston to travel down the cylinder, the forces are equal and opposite so the instance the bullet pushes forward there HAS to be an opposite and equal force against the back of the barrel. Granted there is also a force on the sides of the barrel. I dont distupte that or that a slower burning gun powder builds the preassure up as the bullet moves, while a fast burn will see a high pressure at the start and it will decrease as the bullet travels, increasing the size of the combustion chamber.
In fact this is exactly what high octane additives do, they actually slow down the burn rate of the gas so you get a better power curve and eliminate engine ping.

From Wiki engine knock
Knocking (also called knock, detonation, spark knock or pinging) in spark-ignition internal combustion engines occurs when combustion of the air/fuel mixture in the cylinder starts off correctly in response to ignition by the spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front. The fuel-air charge is meant to be ignited by the spark plug only, and at a precise time in the piston's stroke cycle. The peak of the combustion process no longer occurs at the optimum moment for the four-stroke cycle. The shock wave creates the characteristic metallic "pinging" sound, and cylinder pressure increases dramatically. Effects of engine knocking range from inconsequential to completely destructive. It should not be confused with pre-ignition (or preignition), as they are two separate events.

In any event, the perceived recoil is most likely due to the pressure curve inside the barrel. A high fast rising pressure would give a sharp slap type recoil, where a slower gradual build up of pressure would give a longer "push" type recoil. The bullet may leave the barrel at the same speed, it just had a different acceleration curve to get there.
 
#23 ·
As Bosco said, the pressure is equal all the way around. The pressure expands the cartridge inside the chamber. This is why you have to resize when reloading. Loading too hot will flatten a primer because of head space and the cartridge slamming back within this gap. You can also split cases by loading too hot as the pressure is equal. You are right about Newton but the action is the pressure being released forward out of the barrel. The opposite reaction is recoil. The pressure in the barrel is the same as in an air tank. It is equal all the way around the tank until you open the valve.
 
#26 ·
Engine block and cyclinder = pistol
Piston = bullet

In an internal (stress word INTERNAL) combustion engine all gas expansion is contained in a sealed system. No recoil is felt but the kinetic energy is directed to the one moving part, the piston and from there to the crank shaft...etc.). The expanded gases are then bled off through exhaust valve or valves. I am not an engine designer but I am sure there must be some pretty decent pressure in the axhaust manifold when that valve or valves pop open. Recoil in this case might be called manifold pressure. May not be easily noticed in an engine that weighs several hundred pounds.

In a pistol the expanding gases are also kept in a sealed system and the one moving part is the bullet. Once the bullet leaves the system the energy from the internal gas expansion has done its job as far as moving the bullet down the barrel and now produces the equal and opposite energy against the barrel. Equal and opposite to the force that sent the bullet down range.

If you put a rod (cylinder rod in an engine) into a pistol barrel that kept the bullet from escaping and had a scale on the end, there would be a lot of energy produced (as long as the barrel and breech could contain it). No recoil felt but you would have an extremely dangerous high pressure system searching for a place to discharge its energy.

I do think that there is a certain (slight) amount of backwards energy exerted when breaking the inertia of the seated bullet as it begins to travel down the barrel and this causes the difference in point of impact that pops up when shooting various weight bullets with different velocities.

OMO. Just an opinion, not an argument...:smile:

bosco
 
#27 ·
If the bullet weight has only a slight amount to do with overall recoil then why don't blanks give you the same recoil?

Another example: Take a shot gun shell and pour out the shot. Does that cause any recoil?

Accelerating the weight of the bullet or shot is what causes recoil. Unless physics don't apply to guns.
 
#28 ·
"Equal and opposite to the force that sent the bullet down range."

Figure the amount of pressure that has to be built up in order to send a 124grain .357grain jacketed bullet out of a 3 inch barrel at 1200 feet per second. Compare that to the amount of pressure needed to blow out a piece of wax, cardboard wad or to pop the crimp on a military blank from a shell casing.

Just the primer alone will give a resounding bang from most pistols, add a small charge of very fast powder and cover with a wad or crimp. The pressure builds rapidly and there is the bang, loud but no real energy has been built up since the expanding gases are allowed to escape almost at will from the open barrel..

Again only my opinion. It's been 46 years since I studied physics in college.:confused:Senility maybe:confused:

Maybe someone in the industry can straighten out this confusing issue.

bosco
 
#30 ·
Whether one wall in a closed system is moving or at rest the pressure exerted on all the walls will be equal.

Pascal's Principle
Pascal's principle states that a pressure applied to an enclosed fluid is transmitted everywhere in the fluid. Hence, if a pressure is applied to one side of an enclosed fluid, all the other walls containing the fluid feel the same pressure. The pressure is transmitted without being diminished.

In physics the term fluid refers to either a liquid or a gas. If a pressure is applied to a compressible gas, Pascal's principle still applies, but the volume of the gas will change.
OMO

bosco
 
#31 ·
So you are saying an object can be moved without an equal and opposite reaction.

The back pressure of the gas pushing the bullet up to speed is what causes recoil. Since the bullet is traveling forward you have an equal force applied backward. Recoil starts the instant the bullet moves forward.
 
#40 ·
Not exactly.

Propellants are used to propel projectiles from weapons at comparative high velocities without damage to the weapon itself. The velocity may be as low as 150/ft. per sec. for mortars and some rockets and in excess of 4,000 ft./sec. for other projectiles.

The maximum pressure inside the weapon is another important consideration related to the propellant powder. For a given weapon and projectile, the composition and physical dimensions of the powder determine the pressure-time and velocity-time curves.

This is where it becomes important to understand the factors which affect the burning rate of propellant powders.

In fact, if all the powder in a gun were be to be burned before the projectile in a gun had a chance to move an appreciable distance down the bore, the resulting pressure could blow up the gun. And powder burning rate is usually such that the powder is not completely burned until the projectile has traveled about two-thirds the length of the bore. The result is an increasing volume for the expanding powder gases and therefore a decrease in pressure.

Newton’s third law of motion that that states that there is an equal and opposite reaction is still valid and might be more easily understood with a mortar than with most modern small arms.

Some of my notes on this subject go as far back as my fathers hand written notes starting in 1941 from my dad when he designed automated munitions plants during WWII.

Modern physics has advanced but I think the principles are basically the same today.

No I am not a physics or math authority.
 
#32 ·
To bad this has to be done over the net.. It would be better to be BSing about this over a meal or a few beers.. LOL

True there is a force exerted backwards against the breech as well as against the chamber walls, the barrel and against the bullet. Since the bullet is the only thing allowed to move it moves. According to the prior stated (Good old Pascal) law of physics however, since the system is sealed until the bullet leaves the barrel the pressure in all directions will remain equal only the volume will change.

bosco
 
#33 ·
Somewhere lies the answer. I think true recoil might be that caused by the bullet moving in one direction as it moves down the barrel.

Maybe my gas (excuse me) idea deals more with felt recoil, since once the bullet leaves the barrel the gun has to release the expanded gases contained in the barrel (30,000psi for example) and that forces the gun backwards (rocket effect). A little CO2 cylinder is only under a few hundred psi and will take off when punctured imagine puncturing the same little cylinder with 30,000psi or more.


OMO

bosco
 
#34 ·
There is no pressure build up in a gun without the weight of the bullet. Think of a spring capable accelarating a bullet to 1200 fps in a 3 inch barrel. There would still be quite a bit of recoil but not expanding gasses. It does seem logical to me that the perceived recoil would be less because the gasses would not be there, but you would still have recoil.

My point of contention is recoil starts the instant the bullet moves forward. The jetting of gasses and the weight of the bullet are both factors recoil. BTW, I agree with what was said about the fast and slow burn powders in perceived recoil.

I'll buy the first round..
 
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