Set us straight, my son and I

[sevenbark]

My son is trying to tell me that a 9mm recoil shot from a gun is the same as a 40 S&W shoot from the same gun. I disagree. His opinion comes from all the research he has done. My opinion comes from talking to people. Please set us straight. It has been a long time since I have posted and I am sure the regular crowed is well tired of recoil threads but this has something to help an old man out. It's kind of like discussing which de blade is best on http://www.badgerandblade.com

 

[SHusky57]

This is easy. Rent a Glock 19 and a Glock 23 (they are the same size). One is 9mm and one is 40.

This isn't the kind of question that you need to turn to the internet for an answer.

Heavier rounds are going to have more push-back.
Faster rounds are going to be snappier.

That said, if you are shooting a 40 round and a 9mm with the same power factor they will be about the same recoil I guess. With that said.... most 40 rounds have a higher power factor than 9mm.

Lots of shooters download their 40 to minor power factor for competition. In this case, 40 is as soft as if not more soft than 9mm.
But there is no way a 40 major load is going to have less recoil than a 9mm minor load.

 

[Oro]

This isn't the kind of question that you need to turn to the internet for an answer.

I think it's an excellent question "the internet" can answer quickly and efficiently. In the same gun, it comes down to the round chosen - bullet weight and speed at the muzzle.

Here's a calculator you can use: plug in the variables for the chosen gun and rounds and then you can see the cold fact without having to guess. For powder weight, if you don't know, just put "5" or so for each, it won't really alter the outcome:

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

 

[HankB]

It's a question of momentum. In each case, multiply the weight of the bullet by its velocity - larger product means more recoil. (The powder gasses have an effect too, but I doubt it would affect the outcome in a 9mm/.40 comparison.)

 

[oneounceload]

Since recoil is a factor of several components, of which bullet mass and velocity are parts, you would have to have identical bullet weights and velocities in identical guns

 

[Tommygunn]

Well, I just shot a Stoegar Cougar .40 S&W yesterday for the first time. I found the recoil pretty stout. I've shot 9mm. before from a CZ 75. As far as I can recall I'd say the .40 was greater ... but then you do get into things like them being different guns, different masses, and then there is my memory ... which is normal.
This makes it somewhat subjective. To be sure I would say the most accurate comparison would be between two identical guns, one in each caliber ... but I am not going to buy a 9mm. Cougar or a .40S&W CZ to do the experiment.

 

[LRS_Ranger]

The only identical guns I have shot in both calibers was a SIG 229. The 40 had quite a bit more jump to it. Your son's wrong on this one. If he doesn't believe you, rent both and shoot them both..

 

[RyanM]

Just where did your son do his research? Watching TV? Movies? Video games?

Any other source at all would tell you that, in (roughly) the same gun, factory .40 S&W will have a bunch more recoil than almost any safe 9mm ammo out there.

 

[DFW1911]

My opinion is formed based on years of shooting.

In a word, no, the recoil is not the same. The 9mm is slower to develop and is more of a pushing type of recoil; at times it seems irritatingly slow. The way the cycle develops gives it something of a "soft" feeling.

The .40 recoil has a distinctive snap. As such, the recoil is more "lively" than the 9mm and could be described as jumping a bit.

Neither is harsh. The .40 would be considered "stronger" or having "more" recoil than the 9mm due to the snappiness of the recoil.

If one can't tell the difference by feel it may be due to recoil aversion (all recoil feels the same: too much). Once that passes and the person really starts understanding and feeling how their firearm works they can tell very subtle differences in cartridges and springs (as an example).

SHusky's recommendation is a great one: give it a try and see for yourself.

Have fun!
DFW1911

 

[Zak Smith]

I've owned/shot at least two platforms which were identical other than cartridge, in .40SW and 9x19: Glock and SV/STI. In both cases the .40 had more recoil. This shouldn't be surprising to anyone.

 

[Officers'Wife]

*sigh*

If the 40, 45, 50, 10mm - whatever- recoil is so much you cannot accurately hit your target, go for the 9mm. If not use the larger caliber. You can argue recoil, muzzle energy and knockdown power til the cows come home but the bottom line is simply use what you can hit your target with. In the words of my late uncle- a .22 ball in the brain is far more effective than a .45 through empty air.

 

[Walkalong]

I have a 9MM Conversion barrel for my XD SC .40 cal, and the 9MM has less recoil when both are loaded at near max.

 

[JDGray]

The .40, being a higher pressure cartridge

This needs to be a sticky, as both 9X19, and 40S&W run at the same 35,000 psi. The 9mm +P, runs even higher pressures than the 40. Why does everyone keep saying the 40 Cal is high pressure cartridge, when comparing it to a 9mm?

To the OP, the 40 will give you more recoil if shot in like framed, weight, guns

 

[U-235]

Conservation Of Linear Momentum

Hank B gave a great definition of momentum:

It's a question of momentum. In each case, multiply the weight of the bullet by its velocity - larger product means more recoil. (The powder gasses have an effect too, but I doubt it would affect the outcome in a 9mm/.40 comparison.)

The Law of Conservation of Linear Momentum says that the guns momentum, felt as recoil, will be equal to the bullets momentum. The faster and heavier the bullet, the more momentum the gun will have. For two guns that weigh the same, if you shoot a 9mm and a .40 at the same velocity, the .40 will have more recoil.

 

[Zak Smith]

Free Recoil Energy is the other metric often used to quantify recoil. It uses conservation of momentum but the uses the resulting (recoiling) velocity of the firearm itself to compute the kinetic energy of the firearm (ie the kinetic energy of the firearm hitting you in recoil). It is proportional to (m*v)^2/(firearm mass)

 

[sevenbark]

Yes I agree, shusky I should have covered this in my post. I knew as soon as I walked away from the computer I would have to read this. But I love turning to forums for this kind of info because I love reading good knowledgeable people that love their hobby give answers that make a young person understand and at the same time learn. I am not that person and renting the guns and shooting them is a good idea. Renting saved me from making a mistake on a purchase.

 

[tasco 74]

too many vairibles (sp)...........


LIFE IS SHORT.....

 

[Caliper_Mi]

Hmmm, just speaking of felt recoil here...

I shot my friends Sig (226?) in .40 and I have a Ruger P95 9mm. I don't recall the recoil on the .40 feeling that much different from the 9mm. Of course, I'm pretty sure both had target rounds, so maybe that was why. Or maybe it was the fact that I also shot my g/f's Super Blackhawk .44mag that trip made everything seem light by comparison.

But I agree - the math says .40 will kick harder. Heavier bullet at similar/greater speed means more recoil. How does he work his math?

 

[mljdeckard]

So eliminate the variables. Use guns that are otherwise identical, as some have said, such as the G-17/G-22, G-19/G-23, Beretta 92/96, etc.

Without using math, physics, cameras, and scales, I can tell you, the .40 is very snappy. I carried a G-22 for several years, and was actually relieved to switch back to a 1911 in .45. I find it much tamer.

ANOTHER IDEA, Load a G-22 and a G-17 next to each other, and COVER THE MODEL STAMP. Have someone independent shoot both, and see if they can tell a difference.

 

[Manco]

I think that both 9mm and 40 S&W are pretty snappy, which to me means that the onset of recoil is sudden and rapid, like something popping in your hand. .40 S&W definitely recoils a bit harder due to its heavier bullets (for a given velocity), which usually makes it feel snappier at the same time. For the sake of comparison, .45 ACP out of similar handguns feels heavier but more like a hard punch than a startling pop (they're all pops--it's relative ). Based on the many comments I've read, it seems that most folks prefer the slower albeit heavier recoil of .45 ACP, but after growing accustomed to .40 S&W now, I think I actually prefer the snap because it seems to let me get back on target quickly (with the proper grip, the sights quickly go off target and just as quickly realign). On the other hand, .45 ACP is easier for me to resist, so it's probably a tie; I can't tell much difference with 9mm regarding shooting speed, either, only that it feels lighter overall. None of these calibers, at least to me, are harsh--I could shoot them all day without pain or strain (with a two-handed grip, anyway).

 

[orionengnr]

Having owned both a G-19 and a G-23 (same sized Glocks that chamber the 9mm and .40 cal respectively) I can tell you that your son is mistaken.

If you need to rent one of each to prove this, do so. But common sense and a rudimentary understanding of mathematics should suffice...

 

[badman400]

The .40 S&W is noticeably snappier than the 9mm.

 

[Manco]

I shot my friends Sig (226?) in .40 and I have a Ruger P95 9mm. I don't recall the recoil on the .40 feeling that much different from the 9mm.

The difference is substantial but not large--by the numbers with typical loads, .40 S&W has maybe about 25% greater recoil, both in momentum and force. For some, that's enough of a difference to significantly affect the speed and/or accuracy of their follow-up shots, but it doesn't bother me. By the way, there can be as much difference in felt recoil between different loads in either caliber, as well, to put things in perspective.

But I agree - the math says .40 will kick harder. Heavier bullet at similar/greater speed means more recoil. How does he work his math?

With comparable bullet sectional densities, factory loads in both calibers will be similar in velocity (with a slight advantage usually going to .40 S&W), which means that both the momentum (impulse) and average force of their recoil will be proportional to their bullet weights (e.g. 147 grains for 9mm vis-à-vis 180 grains for .40 S&W--divide and you shall have the answer).

So eliminate the variables. Use guns that are otherwise identical, as some have said, such as the G-17/G-22, G-19/G-23, Beretta 92/96, etc.

Without using math, physics, cameras, and scales, I can tell you, the .40 is very snappy. I carried a G-22 for several years, and was actually relieved to switch back to a 1911 in .45. I find it much tamer.

The greater mass of the 1911 certainly makes a difference, however. Have you ever compared a Glock 22 with a Glock 21?

 

[Frank Ettin]

If you're interested, you can calculate the recoil energy of a given load using the following formula:



WG = Weight of gun in pounds


WB = Weight of bullet in grains


WP = Weight of powder charge in grains


VB = Muzzle velocity of bullet in f/s


I = Interim number (Recoil Impulse in lb/sec)


VG = Recoil velocity of gun (f/s)


EG = Recoil energy of gun (ft lb)



I = [(WB * VB) + (WP * 4000)] / 225218



VG = 32.2 * (I / WG) 



EG = (WG * VG * VG) / 64.4



The formula I've reproduced above, is from the Q&As at http://www.frfrogspad.com/miscella.htm (specifically the question about why some guns of the same caliber kick harder than others). John Schaefer (FrFrog) notes that, "..."4000" is the nominal velocity of the powder gases at the muzzle for commercial smokeless powder and the observed range is between 3700 and 4300 f/s. It is sometimes stated as 4700 in some sources but this is based on observations of artillery, not small arms...."

Let's assume that the two guns, one in .40 S&W and one in 9mm Luger weigh approximately the same. So --

A typical 9mm cartridge, say Federal American Eagle, fires a 124 grain bullet with a muzzle velocity of 1120 fps (Federal's published specs).

A typical .40 S&W cartridge, say Federal American Eagle, fires a 165 grain bullet with a muzzle velocity of 1130 fps (Federal's published specs).

Based on the above formula, recoil energy is directly proportional to bullet weight and muzzle velocity, i. e., the heavier the bullet (at a given velocity) will produce more recoil energy than a lighter one, with the same weight gun; and the greater muzzle velocity (for a given bullet weight) will produce more recoil energy with the same weight gun.

Looking at the 9mm Luger and the .40 S&W, the .40 fires a heavier bullet at a higher muzzle velocity. Therefore the .40 will produce more recoil energy, assuming guns of about the same weight.

Of course, recoil energy and felt recoil are two different things. 



Recoil energy is a precise, physical quantity that is a function of the weight (mass) of the bullet, the weight (mass) of the powder charge, the muzzle velocity of the bullet, the muzzle velocity of the powder gases, and the weight (mass) of the gun. If you have those quantities for a given load in a given gun, you can calculate the amount of recoil energy produced when that load is fired in that gun.



Felt recoil is a subjective matter. It's how you experience the recoil, and it's really something that only you can decide for yourself. 


 

[paintballdude902]

i think the .40sw has way more recoil than a 9mm. in fact i think the .40s&w has more felt recoil than a .45acp. the .45 is more of a push and the .40 a snap. id prefer to shoot a .45 all day rather than a .40