You know, no matter how hard you try, you just can’t get around physics. I got interested in finding a way to compare the recoil of different handguns when I kept seeing guys trying to sell/buy little bitty .380s to/for women because they thought they were “girls’ guns”. I personally think that’s a really bad idea. I know of no way to accurately measure or calculate “felt recoil” for any gun but I did think of a way to offer a possible comparison. It’s relatively easy to calculate the recoil energy of a gun based on the weights of the gun, bullet and powder, along with the velocities. Energy is defined as “The capacity or power to do work, such as the capacity to move an object (of a given mass) by the application of force.” That’s a real number too, actual physics.

The hard part is figuring out the ergonomics of the gun and honestly that is beyond my capabilities at the moment. What I can do is SWAG (Sophisticated Wild Ass Guess) the approximate area of the grip by just multiplying the length and width of the grip. Then I can divide the recoil energy by the area of the grip. I’ll be the first to admit that this isn’t a particularly accurate number and doesn’t take into account the grip shape, grip material, distance below the bore, etc. that all go in to “felt recoil” but I think it at least gives us a starting point to work from.

To calculate the gun’s recoil energy use the following formulas:
Bullet momentum = Bullet weight in grains/225218 x Muzzle velocity.
Powder momentum = Powder weight in grains/225218 x Muzzle velocity x 1.5.
Gun mass = Gun weight in pounds/32.174.
Gun recoil velocity = (Bullet momentum + Powder momentum) / Gun mass.
Gun recoil energy = Gun mass x Gun recoil velocity x Gun recoil velocity.

NOTES: That “225218” is a constant used to convert grains to “slugs”, a unit of mass. The “1.5” in the powder momentum calculation came from a ballistics book that said the powder velocity at the muzzle is usually about 1.5 times the muzzle velocity of the bullet.

In my experience most folks can handle a S&W Model 10 in .38 Special with little trouble. Firing a 158 grain bullet at 800 ft/sec it has recoil energy of about 2.4 foot-pounds. If you take the grip measurements (about 4” high and 1.25” wide) and do a little math you get an “energy per square inch” value of about 0.5. A 1911 in .45 Auto firing a 230 grain bullet at 880 ft/sec has recoil energy of 5.9 ftlbs and an “energy per square inch” value of 1.3. For comparison a Ruger LCP in .380 ACP firing a 90 grain bullet at 960 ft/sec gives you recoil energy of 4.7 ftlbs and an “energy per square inch” value of 3.0.

I put together a spread sheet to enable me to compare different guns. It’s a work in progress but so far I’ve got energies for about fifty handguns, and I’m adding “energy per square inch” values as I have time to measure grips. I’m also comparing guns to a “base” energy value. I’m using a Ruger Mk III .22 as the reference. The Ruger is a “1” on the scale. Other guns are compared by dividing their recoil energy by the Mk III’s. The S&W Model 10 is a 7.6. The LCP is a 14.9 and the 1911 is a 18.8. Cartridges can be compared in a “universal gun”, showing recoil energies as they would be if fired from the same gun. I guess the next step will be to compare the “energy per square inch” value of all of the guns to the Mk III.

The whole point of this exercise is to show folks that little guns, even with mild cartridges, can equal big “felt recoil”. Guys buy their girls a little gun and find out that the girls hate them because they hurt when you shoot them. My daughter didn’t like the LCP but has no problem with an SR9C. Of course little guns can be mastered with practice, but who wants to practice with something that hurts? Maybe that gun you get your girl, especially if it’s the first one, should be something that is fun to shoot.

Good work Punkin...not an easy job either.

I agree totally with your observation that little guns can, and usually do, equal big "felt recoil" mate. I remember back in my pistol shooting days, the "felt recoil" between my Ruger Mk1 in .22 rimfire, my S&W 586 6" barrel .357 Mag and my TC Contender 10" BBL in 30.30 Win wasn't significantly different.

Not before everyone goes off and tells me I'm nuts, of course there was significant difference in the recoil of each pistol, but the recoil in each gun was "delivered" differently because of the ergonomics of each pistol and the type of round fired.

Both the .22 and the .357 would cause more "flip up and twist" than the 30.30 Contender which was more of a big push back. My eldest daughter at 15 yrs old much preferred to shoot my Contender single handed (and hit the IHMSA Turkey target at 150m easily) than she did my 357 Mag 586 with warm+ loads using a two handed hold.

I'll be interested to see the end result when you get it all together Punkin.

you could easily measure push recoil with a butstock off a rifle and strap handgun into/onto it by then putting it in a sled type arrangement. there was a good one on net a while back a moving sled with a sash weight on a rope. the recoil lifted the weight and moved the sled....easy to compare two different loads/guns by amount the sled moved and also by the speed it moved. it wont measure what you feel just the "push'. we hear of young fellas being put off waterfowl hunting all the time as Dad has bought a light single barrel for lad to use then fed it a 3" magnum load which boots the crap out of youngun...feed it a lighter load and a completely different gun...add weight and its better still.
Ive always wondered why a .22 mag with 6" barrel wasnt a prefered sheilahs handgun....plenty of hurt without the big bang.

There is a reason varoius law enforcement agencies have switched from 40 S&W back to 9mm Luger and that would be recoil the ladies and some of the guys couldn't handle in the 40 S&W. Do all the calculating you like and then try a 45 Auto and a 380 Auto on the girl of your choice and I believe they'll dislike the 45 Auto more.

Grum, my daughter doesn't mind the .45s, in 1911s, but doesn't care to shoot the little .380.

Some of those pocket 380's will make a grown man wince.
I have a 357 magnum with a six inch barrel - it is smooth as silk.
I also have an all steel full size 9mm and it is even easier to shoot.
Never had a problem with the 1911's or even the 3 1/2 pound Casull.
I did not like shooting the sp101 with a 3" barrel, even with 38 +P it was more than I enjoyed.
You should see the look on the womens faces at women on target events. We have a couple of those light weight 380's and a few full size nine's and a couple of 45's. The women gravitate to the 45's and 9mm's and don't like the 380's at all.

Pumpkinslinger wrote:

Guys buy their girls a little gun and find out that the girls hate them because they hurt when you shoot them. ... Maybe that gun you get your girl, especially if it’s the first one, should be something that is fun to shoot.

+1 on having one that is fun to shoot. I had my eyes opened one day while at an indoor range. I was thinking about getting a mini for carry that would be smaller and more convenient than my 9mm subcompact Glock. The guy next to me had all sorts of mini pistols from Kahl 9mm to S&W .380s to .22 Mag mini-revolvers. I was amazed how hard they were to shoot accurately and the amount of felt recoil. They were too much for me to handle and I've stuck with my Glock which I can shoot as accurately and fast as my larger frame pistols.

Part of the problem with the mini guns is the long trigger pull too. The more the finger has to pull back the more it tends to be moving your hand position. When you pull the first shot it can be uncomfortable on your hand, you have to adjust to the long trigger pull (like where to position your finger for best ability to pull that far) then after the initial shot you learn (because of pain?) how to place your finger. They're also too dang small in the grip. If you can't put your little finger on the grip then you have compromised control.

On the other hand they're great for concealment and close range. Personally I'd rather have a 1911 trigger pull and a 9mm. I've sampled one mini 1911 in a gun store and haven't decided if the larger heavier gun is for me or not (for concealment) but I'd like to fire one. They have one in .380 and also 9mm.

Suz

Pumpkinslinger wrote:

Grum, my daughter doesn't mind the .45s, in 1911s, but doesn't care to shoot the little .380.

Well, I can't argue with that experience.

I do, however, have problems comprehending how a pocket 380 can "make a grown man wince," etc. I had one that I sold (not because of wince causing recoil) and still have three of them. None of them come close to making me wince.

stuff concealment, a colt dragoon would suit me down to the ground..why???? just because.

I have a Ruger LCP that a number of folks have tried. A few new shooters have been amazed at how "powerful" it was, due to the recoil. I don't have a problem with it and, if I bear down and concentrate, I can get 1.5" groups at 10 yards. On the other hand a friend loaned me a Taurus .380 and that thing did hurt to shoot. Every shot whacked my trigger finger against the guard. (It also shot 4-5" groups at 10 yards.)

Groups of 4" - 5" at 10 yards is "Minute of Criminal" Punkin.

Vince wrote:

Groups of 4" - 5" at 10 yards is "Minute of Criminal" Punkin.

Vince, yep, but that was with me really bearing down and taking my time to shoot. I didn't try any fast, "defensive" type shooting with it. Should have.

454 Casull in a Derringer

I have a cousin-in-law, an engineer, who has a Bond Arms derringer chambered in 45 Colt/410 Shotgun. After his evaluation of how the derringer was assembled; metal thickness, etc., he determined it would stand up easily to the pressure of 454 Casull cartridges. I said, you go first and he did.

He was on blood thinners so the palm of his hand was a little bruised afterwards. I tried it; it stung a little but really wasn't bad and as you can see, muzzle flup wasn't that bad. And no, my handloads weren't downloaded; they were full house loads I'd cooked up for a Freedom Arms Model 83.

We were going to try 460 S&W Magnum carridges but they wouldn't fit.'

Now children, don't try this at home. We are professionals (LOL). Actually we are professionals, just not that kind.

I have a 45/410 derringer that would easily chamber the 454 round but the barrel (chamber) is an investment casting and there is no way I would want to hold on to that hand grenade when it went off!
It shoots a standard 45 colt at about 650 fps and a 410 slug at about 1000. The slug will hold a lot better groups (smaller pattern) than the 45. So, when I carry it I carry it with 410 slugs. My guess is that the 45s don't like the 1.5" jump to the 3/4" of rifling. The slugs don't have a jump - they come out in the rifling.