Heavier bullet = less recoil?

[TheProf]

Is this just my imagination? Or is there physics behind this?

I compared Federal .40 cal (135 grain HP) with that of Winchester .40 (180 grain HP). To my surprise, the 180 grain produced less "bang" (sound and flash) and less recoil than the 135 grain.

I assumed that the 135 grain would produce less resistance to the power charge (due to weighing less) and thus produce less "opposite reaction" (recoil) to me.

1. But to my surprise...the Winchester 180 grain had less recoil? Any explanation to this? (It's been a while since I took physics class...)

2. What are your opinions on this ammo? (Winchester 180 grain)
Does anyone know how the velocity of this ammo?

 

[rcmodel]

The lighter bullet is moving much faster.
The lighter bullet is loaded with more powder to reach the same pressure.

SO, the slap on the hand is going to feel sharper, and the noise louder.

By actual measurement, the heavier bullet load is recoiling more however.
It's just a slower push.

Winchester lists several 180 JHP loads. Most are right at 1,000 FPS.
The Federal 135 is listed at 1,200.

rc

 

[rmfnla]

Is is physics; F=MV (Force = Mass x Velocity)

But, as rc pointed out, your perception may fooled due to othe factors (noise, sharpness of the recoil pulse, etc.).

 

[Vern Humphrey]

No nit-picking, but your question should be, "Heavier bullet = less recoil?"

All grains weigh the same, 1/7,000th of a pound.

You can calculate the recoil velocity of a gun with the formula M1 X V1 = M2 X V2, where:

M1 = the mass of the ejecta (powder and bullet combined)
V1 = the velocity of the ejecta
M2 = the mass of the gun.

A heavy bullet (M1) at low velocity (V1) can produce less recoil velocity (V2) than a lighter bullet at a much higher velocity.

In addition, of course, there are the psychological effects -- chief of which is noise. Wear plugs and muffs and you will find recoil seems a lot tamer.

 

[Tallinar]

Mathematically, the following rounds produce the same muzzle energy of 2497 ft lbs:

180 gr bullet at 2500 fps (.30-06)
500 gr bullet at 1500 fps (.45-70)

Throw these in a recoil calculator, both out of an 8 lb rifle; call it 45.0 grains of powder and 35.0 grains respectively (gonna assume we're using something like 4198 in both cartridges):

Recoil Impulse in lbs/sec: 2.80 and 3.95 respectively
Velocity of recoiling firearm in fps: 11.25 and 15.89 respectively
Free recoil energy in ft/lbs: 15.72 and 31.38 respectively

Now I am no expert, but this calculator tells me that with the same muzzle velocity and gun weight, the one with the heavier bullet at slower velocity is the one that recoils more. HOWEVER, bear in mind the fact that this is calculating FREE RECOIL; not FELT RECOIL. They are different things.

This would somewhat seem to jive with my shoulder experience, though.

 

[Jack2427]

For every action, there is an opposite and equal reaction..............Just a matter of calculating the weights/pressures involved. THEN comes stock design, proper hold, propellant burn rate, et., etc..

 

[JTQ]

For me the "perceived recoil" is greater with the heavier bullets.

In .45 ACP those 165 grain and 185 grain bullets recoil much lighter than the 230 grain projectiles.

 

[Rexster]

It is very normal for 180-grain .40 S&W to feel that it has less recoil. All 180 40's I have fired have seemed milder than all of the 135-165 grain ammo. I think that the 180-grain stuff really has less abrupt acceleration, and so it
just seems milder.

With most other weapons I have fired, heavier-bullet loads have recoiled more.

 

[mjyeagle]

this is backwards from my experance in my 460 45 colt 375 rum their is a sharp difference in recoil as i go up in weight i can shoot a 200 gr bullet with 50 gr of powder one handed easy but 40 gr of the same with 340 gr bullet not even think about it

 

[GRIZ22]

To my surprise, the 180 grain produced less "bang" (sound and flash) and less recoil than the 135 grain.


Muzzle flash tend to get most people's attention more than recoil. They are two separate issues.

 

[heron]

My personal experience (with my 6" GP 100) is that the heavier bullets give more recoil. With .38 spc., any weight is okay to me, but in .357 mag., I actually quit buying the 158 gr rounds because the recoil was painful and hard to control. The most comfortable .357 I've fired was 110 gr., but 125 gr. is perfectly all right.
YMMV.

 

[Zoogster]

Heavier bullets recoil more for a given energy level.
Unless the heavy round is loaded significantly lighter it is going to be recoiling more.

However the felt 'snappiness' with the faster round is going to be greater. The muzzle blast and flash is also going to be much greater.
My experience is that many people perceive the gun or ammo with the greatest muzzle flash and the loudest bang as having recoiled the most, even if it recoils less. The effect of feeling the muzzle blast more also has a psychological impact.
The same people are more likely to anticipate the flash and bang from the lighter less recoiling load if it makes more of an impression each time it is fired.

Generally this perception is reduced the better the hearing protecting is. If the hearing protection is good enough to make them all seem almost equally quiet then the perception that the much louder one is a more powerful hand cannon and by deduction is recoiling more is diminished. Bringing the perception of recoil closer to reality.

 

[Kingofthehill]

I don't have that much to add about recoil vs bullet weight but i am just loving those Federal 135gr hollow points.

I take it out to open land and have performed my own testing with a very very wide range of ammo and through my tests, it has performed extremely well and it really really blows stuff up!... Tested it in all sorts of media and shooting through cover and its has just worked amazingly!

The best .40 HP ive used and the price point is fantastic and that gives you the real opportunity to get familiar shooting it and dump hundreds of rounds through your gun you will carry/use it in.

LOVE THEM!

JOe

 

[Route666]

Actually rmfnla F=MA (acceleration) - the force of the burning powder's gas pressure on the surface of the rear of the projectile will accelerate a heavier mass at less of a rate than a lighter mass, all other things being equal.

This is why 45s feel "pushy" rather than "snappy". The recoil takes longer to happen, so spreads the event out over time and is easier to handle.

This is why heavier projectiles require less powder in reloading as they spend more time in the barrel "absorbing" energy from any gas pressure present, so can use less pressure overall to absorb the same energy as a faster, lighter bullet of the same energy.

 

[SaxonPig]

Newton's Third Law of physics- For every action there is an opposite and equal reaction. More mass going forward out the barrel equals more recoil moving backwards. Know why movie guns don't recoil at all? No projectiles, just blanks. No mass moving forward, no recoil moving backwards.

 

[Marc257]

To me, and this is not a scientifical analysis, my 230 grain 45acp loads have a softer feeling recoil than my 200 grain swc loads that are loaded to the same power factor (velocity x bullet weight).

 

[Walkalong]

I much prefer 180 Gr standard loads over 135 to 165 Gr standard loads for comfort.

 

[918v]

Actually rmfnla F=MA (acceleration) - the force of the burning powder's gas pressure on the surface of the rear of the projectile will accelerate a heavier mass at less of a rate than a lighter mass, all other things being equal.

This is why 45s feel "pushy" rather than "snappy". The recoil takes longer to happen, so spreads the event out over time and is easier to handle.

This is why heavier projectiles require less powder in reloading as they spend more time in the barrel "absorbing" energy from any gas pressure present, so can use less pressure overall to absorb the same energy as a faster, lighter bullet of the same energy.

This^

 

[Red Cent]

I believe those were fired in a semi-auto which inserts a number of items into the equation, the most important is springs.
Without the compensator, shooters have long used heavy bullets and light action springs. If you allow the slide mass an easy start with a heavy bullet you will not get the peceived snap of recoil, nor will the barrel rise as in a light bullet, factory springs.

 

[Cosmik de Bris]

Is is physics; F=MV (Force = Mass x Velocity)

But, as rc pointed out, your perception may fooled due to othe factors (noise, sharpness of the recoil pulse, etc.).

Hmm, well not quite. mass X velocity is momentum (p) not force. F=ma, mass X acceleration or F=dp/dt which is change in momentum.

 

[greyling22]

recoil has been coved pretty well already, but to answer another part of your question,
if all your talking is flash and bang and not recoil, that seems like it would more an effect of what powder is used, not the bullet weight. if it's a slower powder and still burning when it exits the barrel behind the bullet you get more flash and bang. or the same powder with different weight bullets, well the heavier one is generally moving slower, giving the powder more time to burn up in the barrel.

 

[Fremmer]

It's partly the powder and unique properties thereof. The 180 grain round is the standard target round, and is sometimes loaded with specific (and cheap) powder for that general purpose; I'm not sure about the hp stuff you were using. A 135 grain self-defense round may be loaded with powder made for extra velocity. Which generally means more flash and bang.

 

[LexRex]

I think the experience of more perceived recoil on a lighter bullet is true for a single round and similar velocity targets. That is, I would not say that a .38spl recoils more than a 454Casul but I would say that within a specific round, this is true. A .45 ACP golden saber in 185gr will give me more perceived recoil than the same round in 230gr.

 

[Guns and more]

Every action has an equal and opposite reaction.
So M x V = M x V.

Lets say the bullet weighs an ounce and the gun weighs 32 ounces
the velocity of the bullet is 1000 ft/sec.
You can plainly see (as my textbooks always said, even though I didn't) that as the mass of the bullet increases, the velocity of the firearm (recoil) increases also.
Everything else is constant.

In the real world, it's not that simple with friction etc. but in theory if you double the mass of the bullet, you double the recoil. (all else staying constant.)

Think about it. One bullet weighs 1 oz. and another weighs 2 oz. but they both travel 1000 ft/sec. it's going to take a bigger bang, for the 2 oz. bullet, thus more recoil.

(forgive me for using mass and weight interchangeably, but since they are at the same location, it's valid.)

 

[Prosser]

recoil has been coved pretty well already, but to answer another part of your question,
if all your talking is flash and bang and not recoil, that seems like it would more an effect of what powder is used, not the bullet weight. if it's a slower powder and still burning when it exits the barrel behind the bullet you get more flash and bang. or the same powder with different weight bullets, well the heavier one is generally moving slower, giving the powder more time to burn up in the barrel.

It's partly the powder and unique properties thereof. The 180 grain round is the standard target round, and is sometimes loaded with specific (and cheap) powder for that general purpose; I'm not sure about the hp stuff you were using. A 135 grain self-defense round may be loaded with powder made for extra velocity. Which generally means more flash and bang.

Excellent points. Burn rate is the final component. Usually target loads are fast burning, and therefore require lesser charges to generate the same pressure as the heavier powders, that excellerates the bullets quickly.

That said, commercial loads are often loaded with whatever IS the cheapest, most profit, not what is the best load. Other ideas are to tailor the load by burn rate to the length of barrel it's being shot out of.

Some of the loads, Federals "low recoil" 357 comes to mind, are pretty close to .... "Low recoil" Sure, compared to a 458 Lott, but not compared to any of the other avaliable .357 loads. Just false advertizing, or, at the least the ones I compared to a bunch of other .357 loads.

Also, a heavier bullet can hold in place longer, allowing a slower burning powder to build to maximum pressure, prior to the bullet moving. A slower burning powder can create a longer, more even felt recoil, for an equal
speed and weight bullet.

All this aside, your observations on the two loads cannot really be generalized
to general characteristics. You have a specific incidence, and, you need to examine the facts of that situation to determine what causes that perception.

The first step would be to find out what velocity the loads are moving out of YOUR gun. Changing gun barrel lengths, and designs could change the perception of recoil. Then figure out what powders are being used, and what primers. Most ammo companies use powders we can't buy, and, it's unlikely they are going to give you the powder, and the burn rate. You can pull a bullet, and, look at and weigh the powder. Then compare it to the common reloading tables.

Some folks like Buffalobore, actually use low flash, low smoke powders for self defense round, like Winchester 297, which is not commercially avaliable.

What I'm getting at, is it's not easy to figure it out.