Bullet weight vs recoil

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UziLand

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Gentlemen and fellow addicts :). I read somewhere the other day (I think it was here, this is the only forum I am on) that the heavier the bullet, the lighter the recoil. Now, I have been loading since Bill Clinton's first term, for obvious reasons.
But could someone explain this to me. I don't get heavy into the ballsitics but I measure recoil by what I feel. Take a 38 special for example, to me a 158gr bullet recoils more than a 125gr pill. I assumed that a heavier bullet, built more pressure before exiting the barrel as it takes more to move it. I realize that powders and charge weights, primers, the gun itself, etc. Make a difference. I am just asking how a heavier bullet can have lower recoil, in this case lets reference a wheel gun like the 38/357 mentioned above. 6" bbl.

Thanks,
 
I'm not for sure but I'd imagine that pistol recoil follows rifle recoil as far as bullet weights go.

I mean the "reduced recoil" ammo that Remington and others make use lighter bullets...
 
It depends on powder. Powders either give kind of a snap recoil or push recoil which will give a perceived recoil.

In my opinion, fast powders give more of a snap while slow powders give more of a push. So I mentally perceive the recoil differently. Think Titegroup vs Unique.
 
Here is a recoil computer.

http://www.handloads.com/calc/recoil.asp

Enter the numbers and it will tell you the facts, load vs load.

I agree there is actual recoil, but more importantly 'felt recoil'.

Light bullets are faster and tend to feel like they slap your hand more.
Heaver bullets feel more like a slower push without the sting.

rc
 
Lookup impulse power. Longer barrel, same acceleration divided by more time is less impulse power.

weight of firearm has a role as well, we need a formula!

edfardos
 
Don't need no Steenk'n formula.

It's built into the Recoil Calculator I posted in post #7.

rc
 
Slower burn powders with heaver bullets will produce more of a push than snappy feel.

But you need to load down on the lower end to get the lighter feel. With simi-autos the heaver bullets help work the action at the lighter loads.
 
You can use an online recoil calculator as RC suggest or you can read this and gain an understanding of how Free Energy Recoil is calculated. The merit to reading the link is you can see how all the different variables figure into the equation and which variables weigh in heavier. It's all in the numbers. :)

Ron
 
I know that i actually prefer the recoil from my 1911 with a 230g bullet compared to a 115g 9mm load (1/2 the weight). I would imagine that part of the difference may also come from the weight of the gun and spring weights etc. but the difference is significant.
 
The original statement was oversimplified.

If you were using the exact same powder loaded to the exact same pressure the recoil impulse would be greater with the heavier bullet. The felt recoil would also be greater.

For a gun with an action that is neither recoil nor gas operated, loads could simply be reduced. For example, it's easy to download wadcutters in a revolver and still achieve reliable function. However, most semi auto firearms have actions that respond to pressure within the chamber and/or gas system. (I am simplifying this a little) Simply reducing the load in a gun of this type (most modern sporting rifles and nearly all semi-auto pistols) will result in unreliable function since the action of the weapon relies on certain pressure thresholds to be met in order for it to function.

Here's the tricky part. For very soft shooting loads, faster powders are used in combination with heavier bullets. The powders with the faster burn rates build pressure much more rapidly with a smaller charge and less total combustion gases created. This in combination with the heavier bullet allows for the development of a reduced power load that has a pressure curve with a much steeper slope than the slope that would be generated by a slower powder. The pressure of a well-constructed reduced load cartridge will be just enough to rapidly peak just above the threshold necessary for reliable function, and then it will begin to drop off just as rapidly. The ideal result is a significant reduction in recoil impulse, felt recoil, and also a significant reduction in velocity over standard loadings.

I hope this helps and doesn't just confuse things further.
 
rc:
Light bullets are faster and tend to feel like they slap your hand more.
Heaver bullets feel more like a slower push without the sting.
Click to expand...

The 9mm pistol's "felt" recoil is less with the heavier bullets. 115gr="Snap". 147gr = "Push"
Inertia vs bullet acceleration rate? Whether the math agrees or not, try it. It's a fact.
 
Heh, Heh, Heh!!!! Boy you opened up a can of worms here. Boy o Boy. You know RCMODEL gave you a great source, but then others have made some good contributions because some of us are most sensitive to POP, some to PUSH some to CRACK, and some of us just can't stand the flash like a FIRECRACKER right in front of your face. (keep your eyes open the whole shot and you will see what I mean).

So we cringe, flinch, eye flinch, anticipate etc. etc. -even though we shouldn't and just get used to what impacts us the least as far as what we perceive or feel. But, the chart gives you the most objective scoop.

regards,
:):)
 
What about felt recoil and muzzle rise?
They are sometimes decoupled, where there is more felt recoil but the handgun's sights return to the target faster.

A quicker return to target is desirable even if there's more felt recoil.
 
That's the word I was looking for....felt. Lol. Not perceived.
Click to expand...

Felt and perceived (AKA "kick") are one and the same. There are two different recoils: ACTUAL which is a math calculation (see RC's post with link) and FELT which is how it feels to YOU. With a handgun, that will depend on the grip size and style, your hands, how you hold the gun, etc.

In the same gun, the heavier bullet will have more actual recoil. How it feels to you versus the other will be different. Taking the same load and shooting it in a revolver and a semi, the semi will feel lighter due to the movement of the slide
 
1SOW said:
rc:


The 9mm pistol's "felt" recoil is less with the heavier bullets. 115gr="Snap". 147gr = "Push"
Inertia vs bullet acceleration rate? Whether the math agrees or not, try it. It's a fact.
Click to expand...
I agree and i think a key point was missing in the earlier posts, for my percieved intent of the question.

"In the same handgun" the felt recoil is less with a heavier bullet. From my STAR 30M the felt recoil is less with a 124gr compared to the 115gr bullet.

A 380 auto compared to a 9mm and 45 auto will feel differnt with the same weighted bullet (if able to compare).
 
Alot of great information here. Thanks much. Reloadron and rcmodel, thanks for the links.
I have been working on light loads for the wife to make her more comfy with her new S&W MP 9mm. I also put a laser in th bbl and had her dry fire to demonstrate what her "flinch" was doing. Then she understood. I will try working up some 124's today and test both in my MP Pro. Of course, I can only use the powders at hand :cuss:
Thanks again
 
UziLand said:
Gentlemen and fellow addicts :). I read somewhere the other day (I think it was here, this is the only forum I am on) that the heavier the bullet, the lighter the recoil. Now, I have been loading since Bill Clinton's first term, for obvious reasons.
But could someone explain this to me. I don't get heavy into the ballsitics but I measure recoil by what I feel. Take a 38 special for example, to me a 158gr bullet recoils more than a 125gr pill. I assumed that a heavier bullet, built more pressure before exiting the barrel as it takes more to move it. I realize that powders and charge weights, primers, the gun itself, etc. Make a difference. I am just asking how a heavier bullet can have lower recoil, in this case lets reference a wheel gun like the 38/357 mentioned above. 6" bbl.

Thanks,
Click to expand...

Something that needs considered and seems to be overlooked is the Velocity which plays a key roll in calculating FRE (Free Energy Recoil). Using the FRE calculator linked to by RC and using 38 Special load data here is about what you will get:

Load Data
Bullet Weight = 158 grain
Velocity = 800 FPS
Powder Charge = 4.2 grains
Handgun Weight = 2.35 Lb.

Based on Hornady 9th Edition the above load will yield about 800 FPS of Muzzle Velocity.

The online calculator will yield a result around 2.77 Lb. of force. Now if I drive a 125 grain bullet to that same velocity:

Load Data
Bullet Weight = 125 grain
Velocity = 800 FPS
Powder Charge = 5.1 grains
Handgun Weight = 2.35 Lb.

The only variables changed are bullet weight and powder charge weight. The online calculator will yield a result around 1.95 Lb of force.

The handgun is a S&W Model 27 having a 6" barrel but barrel length matters not, obviously within reason. The revolver weighs around 2.35 Lb. So yes, all things considered between a 158 grain bullet with a muzzle velocity of 800 FPS and a 125 grain bullet with the same muzzle velocity the FRE of the 158 grain bullet is greater. Only at the same velocity. If I push that 125 grain bullet faster to let's say 950 FPS using another load of 5.8 grains of powder charge I get around 2.72 Lb of FRE. Not much difference at all.

The powder charges happen to have been Unique but if I push that same 125 grain bullet to 1,000 FPS using 7.1 grains of IMR 800X or Vihta 3N37 the FRE will exceed the 158 grain bullet.

How the FRE is distributed to the shooters hand is another story. That becomes a function of the revolver design with a focus on the specific grip design. Much like muzzle climb is a function of the revolver design.

While online little calculators can be a useful tool they can also be as useless as teats on a bull if we don't know how they derive the results. That is why I earlier referenced the formula used in a SAAMI white paper. We should also know that loading manual muzzle velocity is BS because each gun will be different. You want to know how fast a bullet is traveling? Chronograph it.

Ron
 
I ran my .357 mag loads through the calculator and it indicates that a 125 gr. bullet v.s. a 158 gr. bullet, that the 125 gr. bullet produces more recoil. But that too is using lots of H110 in both loads.

As for felt recoil, the 125's produce quite a bit more felt recoil, which is consistent with the recoil calculator.

GS
 
Momentum is conserved in collusions not kinetic energy. Momentum is mass times velocity. Apparent or felt recoil is subjective, momentum is not.

If the lighter bullet goes faster and thus the momentum is the same, the recoil will be the same.
 
There's recoil and then there's recoil. Actual recoil is easily calculated, and the tool for calculating it has been provided.

Then there's perceived recoil. A lot of that has to do with things other than the free recoil of the gun. Noise, blast, flash, impulse... all these play a role. So do things regarding the gun itself and its interaction with your anatomy.

The former is just math, and not subjective. The latter includes many subjective factors, since everyone's brain weights those things differently. Some find a heavier bullet at a lower speed (but equivalent momentum) to have more perceived recoil, while others feel the opposite to be true. Since we're talking about subjective matters, whether you think you prefer the recoil of a light projectile or a heavy projectile, you're right.
 
I always looked at it as more powder= more recoil. For me in 9mm if I'm loading to minor power factor In the same gun a 168gr bullet takes half the powder that a 115gr does. And without a doubt it has much less recoil and muzzle rise.
 
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