recoil, real or inferred!!!

D

Doc Holliday 1950

New member
This is driving me crazy. I have no problem about this for myself but must get this straight for my better half. All are invited to chime in.

"Does muzzle Velocity and Muzzle Energy relate to felt recoil or kick?
Rather the lower the MV and ME the less felt recoil.
Is this correct? Of course I'm referring to the LCR for Mrs. Doc.
Sorry if this sounds stupid but I want to make sure about this. Also, does the weight of the bullet affect the two forces or is it strictly MV and ME"?

Doc
 
I look at the recoil math real simply --- as primarily a combination of :

a. weight of the gun
b. weight of the bullet
c. velocity of the round

For a given bullet ...( in 38 spl or whatever )....lower velocity and a lighter bullet for any given gun ...will give you less recoil. But the problem is - most of the time, when you look at commercial ammo - the lighter the bullet the faster the velocity.

Adding weight to a give model of handgun is not practical ...but picking a gun that is 6 - 8 oz heavier ( longer barrel, steel over alloy, etc ) usually reduces the recoil at least 15%. But you have to keep the selection in a model that fits the shooters hands....so sometimes you can't go a lot bigger...or heavier.

Reload something to suit her..../ for my young grandkids in K frame revolvers...I load a lower velocity bullet in .38 spl for them to shoot...and in general, I want to use a faster powder.../ vs what I might shoot in the same gun ( in a hotter .38 spl or even a .357 Mag )...
 
Doc,A long time ago while trying to answer a similar type question for me a man said:"You don't have to be an electrician to turn on the lights;"Just move the switch!"Knowing this,the answer is YES. :D
 
IMHO the shape of the grip, the size of the hand, and how the two of them interact is a very important factor. Several times I have changed grips with the result that the felt recoil changed significantly.
 
Does muzzle Velocity and Muzzle Energy relate to felt recoil or kick?
Click to expand...

IMO, total recoil most closely correlates with momentum. You can calculate momentum for comparative purposes as

P = 4.4 M*v (in lb-msec)

where M is bullet mass in grains, and v is muzzle velocity in thousands of feet per second. (I.e, for 1200 ft/sec, v = 1.2).

Note that the units for P above are one-thousandth smaller than the standard units of lb-sec, so divide by 1000 if you want to stay standard.

Also, IMO energy most closely correlates with tissue damage. You can calculate energy as

E = 2.2 M*v*v, where E is in ft-lbs, and M and v are defined as for P.

For two cartridges with the same energy E, the one with the heavier bullet will have a higher momentum. But, for two cartridges with the same momentum, the one with the lighter bullet will feel "snappier" ... the momentum reaches its full value more quickly.

Some people seem to perceive recoil more as real total momentum, but other people seem to be more sensitive to "snappiness". An example is that 230gr .45acp's have a fairly high momentum, but fairly low energy. They produce a slower, but heavy, recoil. On the other hand, 165gr .40S&W's have less momentum, more energy, and snappier recoil. Some people perceive the .40's as recoiling more, and others perceive .the .45acp's as recoiling more.

[ADDENDUM]: One other issue: the weight of the gun doesn't change the momentum ultimately transferred to the shooter ... but it DOES affect how snappy that total momentum feels to the shooter ... a heavier gun will spread out that total recoil over a longer time interval. A heavier gun will feel less snappy for the same cartridge, and will be easier and nicer to shoot (but not as nice to carry).
 
Last edited:
Doc,A long time ago while trying to answer a similar type question for me a man said:"You don't have to be an electrician to turn on the lights;"Just move the switch!"Knowing this,the answer is YES.
__________________
Click to expand...

Skeets,

"Hot Dam" you are O K ....:):)
 
Some great answers today, and Skeets gets the put it in simple and direct terms award:cool:

My recoil rule of thumb: The heavier the bullet and the faster it travels, the greater the felt recoil.
 
Yes all of you explained this and I completely understand .
Thanks everyone who both posted online and in private for all your help. My wife is going to become my shooting partner and that makes me a happy oldtimer. My original problem was I didn't realize that when we bought the LCR 357, my wife, wanted the laser grips. I used to have them on a Rossi 26 oz 2"
and there was almost "no pain" even using mag loads so I didn't give it a thought.
Now with the combo of steel/poly at 16+ ozs. it's a bit different. I shot it this week and used 38 P+ ammo and the web between my thumb and trigger tigers still is sore. Hence the frantic quest for a more forgiving load to practice on for her.
If this doesn't work, then the CT laser grips goes and the Hogue Tamer grips gets put on.

Doc
 
I look at the recoil math real simply --- as primarily a combination of :

a. weight of the gun
b. weight of the bullet
c. velocity of the round
Click to expand...

There is a 4th factor that must be included, the weight of the powder charge. It is not uncommon to be able to shoot equal bullet weights to the same velocity and use considerably less powder in some cases. Depends on the cartridge case design and the powder chosen.

Plug in the numbers here for actual recoil energy

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

You also have to consider recoil velocity. In other words, how fast is the gun recoiling. All things being equal heavier loads at slower speeds recoil slower and even though they may have the same recoil energy and are more comfortable.

Semi-auto guns and recoil reduction devices such as recoil pads, synthetic grips or stocks also slow down recoil velocity and will be more comfortable to shoot than fixed breach guns with more solid stocks/grips.

The wider the grip/stock you have spreads out recoil over a larger portion of your hand or shoulder. A Glock 21 in 45 ACP with its wide grip and plastic frame that flexes slightly will have much less recoil than a heavier 1911 with it's narrow steel frame.

And part of the problem is "between the ears". Often people have irrational perceptions of recoil. Some convince themselves stuff kicks a lot harder than it really does. Noise is part of this. The louder the gun is the more it convinces our brains it kicks.

A small, lightweight, short barreled revolver in a magnum chambering is the perfect storm for recoil. Both real, and imagined.
 
There is a 4th factor that must be included, the weight of the powder charge. It is not uncommon to be able to shoot equal bullet weights to the same velocity and use considerably less powder in some cases. Depends on the cartridge case design and the powder chosen.
Click to expand...

Jim, I would make the argument that this is not a 4th factor - but rather a factor that contributes to "c" velocity.

I would argue that the 4th factor is time as you alluded to. I.E., some bullet/powder combinations produce their energy (and therefore, recoil) over a longer period than other bullet/powder combinations. Even though mathematically the recoil energy calculated may be the same, the shooter may be able to perceive the recoil differently from the two charges.
 
Different powders can produce the same velocity with different charge weights. A powder that requires a heavier charge to propel a bullet to the same velocity that a different powder gets with a lower charge will produce more recoil.

For example, a charge of six grains of powder "a" moves a 130 grain bullet out of the snubby at 800 fps. Powder "b" moves the same 130 bullet out of the barrel the same 800 fps speed but only uses 3.5 grains. Powder "a" generates slightly more recoil than powder "b".
 
Powder "a" generates slightly more recoil than powder "b".
Click to expand...

Powder "a" may generate more "perceived" recoil because it happens over a shorter period of time. Mathematically calculated recoil energy should be the same.
 
Yes, and the reason is simply that the "M" (mass) moving down the barrel is NOT just the bullet mass but the mass of the powder gas and unburned powder as well. In handguns, the mass of the powder and gas can usually be ignored since the powder charge weighs little in comparison to the bullet (4 grains vs. 158 grains, for example). But in a rifle, where the weight of the powder is perhaps one third the weight of the bullet (50 grains vs. 150 grains), the powder charge weight adds significantly to recoil.

At this point, I know someone is going to ask what the difference is between weight and mass. Well, on earth at sea-level gravity, there is none. But in space, there is. Outside a gravitational field, an object has no weight, but it still has mass.

If we moved the OK Corral to space, the bullets would have no weight and no one would be hurt, right? Nope. The bullets would still have mass and the guys hit by them would be just as dead as they were in Tombstone.

Jim
 
Powder "a" may generate more "perceived" recoil because it happens over a shorter period of time. Mathematically calculated recoil energy should be the same.
Click to expand...


The two Jims are correct. A heavier charge of powder "a" to get the same bullet to the same velocity as powder "b" will mathematically produce more recoil. link

Muzzle brakes wouldn't work if the weight and speed of the powder charge didn't add to recoil.
 
I might mention that also contributing to recoil is the "jet" effect of powder gas exiting the barrel after the bullet. That is also usually ignored but will vary with the charge and type of powder. There is also a small jet effect from the precursor wave, the air in the barrel when the gun is fired and any gas that has leaked around the bullet being pushed out of the barrel ahead of the bullet.

Jim
 
Momentum conservation and energy are important parts, but what matters to you is felt recoil, some subjective combination of force backwards on your hand and torque of the gun about your hand.

What actually happens is, the gun accelerates backwards by force applied to the breech face. In a revolver the breech face is the frame of the gun, but in a pistol the breech face moves backwards a bit with the barrel, unlocks, and then moves back a lot by pushing against a spring. Force is change in momentum divided by the time it takes for the momentum to change, so the pistol will have a smaller force on your hand than the revolver even if the guns weigh the same and fire identical bullets, because it takes longer for the momentum to be fully applied to the whole pistol.

That's the linear part, but your hand is holding the grip, and the grip is below the barrel, so this force is also a torque through the distance of the barrel above the grip. A large offset will feel more like the gun tipping backwards than like a fastball into your palm, so generally larger guns won't slam your hands as much as smaller guns.

All this explains why my MP340 is such a beast, and my wife won't fire it even with .38 specials. :D It is light (high recoil energy), it is a revolver (breech face transfers the force instantly to the whole frame), and the barrel offset is small (more like a fastball into the palm).
 
Mass X Velocity^2

But I've also found that a gun has more perceived recoil the louder it is and the larger the muzzle flash. Not physical or felt recoil, just how people think about it. So good ear and eye protection is a first step toward handling recoil.
 
You must log in or register to reply here.
Back
Top