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Picture of George43
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Which factory 9mm bullet would produce more felt recoil in a pistol 115 grain or 140 grain?

Thanks.


A gun in the hand is worth more than ten policemen on the phone.
The American Revolution was carried out by a group of gun toting religious zealots.
 
Posts: 3512 | Location: Spring, Texas | Registered: June 26, 2012Reply With QuoteReport This Post
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Depends how it's loaded. Most will tell you that a heavier bullet produces less recoil, which flies in the face of newton's third law, assuming the same velocity of projectile.

It makes more sense when you consider that heavier bullets, as a rule, go down range more slowly.

Because pushing a heavier bullet to the same given velocity increases chamber pressure for a given powder, and because there are powder limits, and because a heavier bullet will hit with the same impact force when fired at a slower speed (and other reasons), heavier bullets have lower muzzle velocities, and consequently, depending on how much lower, they also have lower recoil (every reaction has an equal and opposite reaction). The actual amount of reduced recoil depends on several factors, but mostly on just how fast that bullet is pushed out of the barrel, and the way in which it's pushed (which as to do with powder burn rates and where most of the burning is taking place).

Generally speaking, heavier bullets produce less recoil. It's just not because they're heavier.

The competition world uses "power factor" for ammunition, which is simply bullet weight times velocity, divided by a thousand. It's a standard that makes an effort to determine the minimum "power" that a bullet must have, to be legal for competition. For most 9mm "minor," for example, it's a power factor of 125.

A 115 grain bullet must be traveling 1087 feet per second to achieve a 125 power factor. A 147 grain bullet must be traveling at 850 feet per second to achieve the same thing. A 180 grain bullet must do 694 fps, a 200 grain bullet 625 fps, and a 230 grain bullet only 543 feet per second...ridiculously slow, even for .45 ACP.

The energy of each of the bullets above compares at:
115 grain: 302 ft/lbs
147 grain: 236 ft/lbs
180 grain: 192 ft/lbs
200 grain: 173 ft/lbs
230 grain: 151 ft/lbs

In the case of the latter, the 230 grain .45 acp bullet actually has less muzzle energy than a 32 grain .22LR Stinger bullet traveling at 1640 fps (191 ft/lbs energy). The .45 acp in this example is operating at a power factor of 125, while that .22 long rifle bullet, with greater muzzle energy, only makes a power factor of 52. Confusing?

Generally speaking, and very generally speaking, for a given velocity, the lighter bullet has less recoil. For a given weight of bullet, the lower velocity has less recoil. For a given bullet chambering (9X19, .40, .45acp, etc), the heavier bullet will be traveling slower and will have lower recoil.

Many competition speed shooters go with heavier bullets, close to the minimum power factor for what they're shooting, to take advantage of the reduced recoil. If you're going for a defensive round and want the best terminal ballistics, it depends what you're trying to achieve with the bullet: most today are expanding bullets (hollowpoints), which must meet a minimum velocity threshold to expand, but also must penetrate enough to be effective, and the more they expand, the less they penetrate, unless they're really cooking, at which point both can be achieved. That in turn goes to bullet design, as well as the medium through which the bullet is fired, plus velocity, etc. Most defensive ammunition is loaded to a velocity deemed ideal for that cartridge. Barrel length and type then sets velocity (shorter barrels have lower velocities, polyagonal barrels--glock, HK, etc-- have higher velocities for a given length, etc).

All of which is to say that very generally speaking, buy the heavier ammo for your defensive needs, to get the lower recoil...which is far from being true in all cases, but close enough for some. Depending on how it's loaded, your 140 grain should be lower in velocity, and lower in recoil. It may also be lower in penetration and expansion, depending on the bullet, what it's being shot from, and how it's loaded.

Is that 140 grain fmj S&B ammo, by chance? If so, they advertise at 1001 fps and 309 ft/lbs muzzle energy, which equates to a power factor of 140. Their full metal jacket 115 grain ammunition advertises at 1237 fps, with 391 ft/lbs energy, and a power factor of 142; nearly identical power factor, substantially different muzzle energy and very different velocities. You're likely to feel a little less recoil with the heavier bullet, but that may be more perception than reality.
 
Posts: 4964 | Registered: September 13, 2006Reply With QuoteReport This Post
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Thanks Guppy for all of that data. In my instance I have two considerations: I am 76 years old am concerned on follow up shots and arthritis. I also will not be shooting beyond 20 to 30 feet, so external ballistics is not a real concern. So I guess a heavier bullet might produce less felt recoil in a G19?


A gun in the hand is worth more than ten policemen on the phone.
The American Revolution was carried out by a group of gun toting religious zealots.
 
Posts: 3512 | Location: Spring, Texas | Registered: June 26, 2012Reply With QuoteReport This Post
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George,

Generally, yes.

If you're going to be shooting defensively, then 147 grain factory loadings will generally be your best bet. There are plenty of good ones to choose from. 147 grain in the most commonly found heavy 9mm bullet, though you can find a few that are a little heavier. 147 is often referred to as "subsonic," and usually the lowest recoil.

Many years ago the FBI had a shooting in Miami that involved the death of agents and the failure of their 9mm to stop the suspect. Some felt that the slower 147 grain ammunition was at fault and that it didn't expand. The trend went back to 115 grain and 124 grain.

Today, common wisdom is that most of what you'll find on the shelf will be adequate, and in 9mm, the 147 grain offerings will provide the lowest recoil. After that, it's all about shot placement.

If you're shooting for sport and it's shooting that has a minimum power factor, then 125 will be the threshold for most, and your heavier bullets will definitely give you an advantage there.

There are several "low recoil" loadings available. They are lower velocity, which is primarily how they achieve less recoil. That does mean lower energy, but there's always a trade off.

If you're shooting from a short barrel, Speer Gold Dot also comes in a short barrel offering, which is intended to keep the velocity up, despite using a shorter barrel.

Federal makes a low-recoil product, and Winchester Train and Defend is also lower recoil, with reportedly good expansion and penetration.

Avoid ammunition labeled +P or +P+ as these operate at higher chamber pressures, faster velocities, and have more recoil. I'd avoid boutique brands that offer anything unusual (really light rounds traveling at very high velocities, fragmented rounds, weird spiral bullets, etc). Many don't do what they advertise, may have feeding or cycling issues, and may not produce much benefit so far as recoil...and they tend to be more expensive.
 
Posts: 4964 | Registered: September 13, 2006Reply With QuoteReport This Post
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Good discussion thus far. When recoil of similar cartridges in the same gun is being discussed I always point out that all the methods of calculating recoil to achieve figures in scientific terms that I’m familiar with boil down to momentum which is mass times velocity. And if all we’re doing is comparing one load against another, then the “power factor” calculation is good enough: bullet weight in grains times velocity in feet per second (and divide by 1000 to obtain a more manageable figure):

Using the factory ballistics of Blazer ammunition as an example:

115 grains at 1145 fps = 132 PF
124 grains at 1090 fps = 135 PF
147 grains at 950 fps = 140 PF

They are so close that the difference probably won’t be felt by most people, but the 115 grain load will have a little less felt recoil than the other two.

And as an aside, the fact that many 115 grain FMJ training loads produce less recoil is also why so many guns, especially when new, experience malfunctions caused by low slide velocity, and which is also a function of bullet momentum.




“The fundamental cause of trouble in the world today is that the stupid are cocksure while the intelligent are full of doubt.”
— Bertrand Russell
 
Posts: 42220 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
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Hi George,

My real world experience is somewhat different from sns3guppy's report. And I mean no disrespect to his math.

Due to the heavy recoil of even regular range bullets in my 38 Special in S&W 340 revolver weighing in at 11 ounces, a couple weeks ago I began seeking a easier to shoot cartridge for my concealed carry students to use. Common self defense loads at 125 to 147 grains are just really unpleasant in that lightweight gun.

My students did not like to shoot it and at age 75 myself, I preferred my Sig P365 or 938.

I reasoned that a light weight bullet might give me less recoil than shoving a heavy bullet down the barrel. I located a 38 Special cartridge with a 81 grain bullet made by Fort Scott Munitions that is quite acceptable to shoot. Recoil is maybe 75-80% of a common range bullet. And I already have students liking the round.

I suspect that the same experience will await you if you try their 9mm bullet also. And that is my suggestion - buy a box and try it out. Also their video show this 9mm bullet going through the car door of a rolled down window, then 16 inches into ballistic gel. The Hornady or Speer Gold Dot did not make it to the gel.


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Posts: 1384 | Location: Denver Area Colorado | Registered: December 14, 2008Reply With QuoteReport This Post
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This is why simply stating heavy bullets have less recoil is generally accepted, but not accurate.

All factors must be considered for a given load, as previously indicated. The type of barrel and firearm (and rifling), length of barrel, bullet weight, velocity, powder type, and even primer type; all are factors in determining velocity of the bullet. Temperature of the ammunition, atmosphere, and firearm also make a difference, and some powders (Titegroup, for example) are reverse-temperature sensitive, while others are simply temperature sensitive, and some aren't. Moreover, position of the powder in the cartridge, and whether the cartridge is a "compressed load" (one in which the powder volume is compressed by the bullet) make a difference, as does whether the powder is "position sensitive" (small charge lays along the lower side of the case in the chamber). The burn rate of the powder makes a difference, and whether the powder burns primary in the chamber and forcing cone area, or continues to burn and expand all the way down the barrel (and outside the barrel, in the case of many short barrel firearms): all factors.

The recoil that's felt by the user is often subjective; a wider back strap tends to produce a lesser impression of recoil than thin or sharp or textured backstrap, particularly in the area fo the webbing of the thumb and forefinger.

A heavier firearm will be less displaced by recoil, but at the same time will not be as fast to move on target, especially transitioning between targets. Depending on what you're firing and skill and experience, the difference may be noticeable or negligible.

What one shooter feels will not be what another shooter perceives.

Time to get back on target is going to be faster than you can move the pistol back, if the grip is correct: it will recoil and return to the target faster than you can act, and faster than you can press the trigger. I wouldn't choose a load based on the time to return to the target after the first shot; with a proper grip, the pistol does that by itself. The issue of what's going to affect arthritis is entirely different, largely subjective, and unfortunately, the effects of trying this load or that may not be felt right away.

A longer barrel will lose less energy, produce a faster round, with more muzzle energy, but will often be perceived as having less "snap," and as a milder-shooting firearm.

The actual recoil will be as discussed previously, and that comes down to the velocity of the bullet and the weight, and must be considered in the context of the firearm in use (light vs. heavy, design, etc). Remember that felt recoil or what the shooter perceives, vs. what actually is, are nearly always two entirely different subjects.
 
Posts: 4964 | Registered: September 13, 2006Reply With QuoteReport This Post
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As noted above buy a box of both and see what produces the least amount of recoil. Much of the 9mm is underpowered when compared to brands like Underwood and some self defense ammo. I bought some Fioochi a while back and it would not cycle in my Sig 226 it was so underpowered. Of course, my Glock 19 cycled fine. It felt like shooting 22 lr.
 
Posts: 8590 | Location: Stuck at home | Registered: January 02, 2015Reply With QuoteReport This Post
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Physics question - is the felt recoil proportionate to the resulting muzzle energy? Remember, the foot pounds is the calculation of kinetic energy which is 1/2 the mass times the square of the velocity. Not trying to poo-poo on my fellow USPSA members, but power factor is not a true measure of the kinetic energy. For example, a 10% increase in velocity results in a 21% increase in kinetic energy for the same bullet weight.

I once was told that the amount of recoil was the direct result of the amount of the powder charge - don't know if that is the case, though.
 
Posts: 332 | Location: suwanee, ga | Registered: January 01, 2007Reply With QuoteReport This Post
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The recoil calculation formulas I have seen over the years all involve projectile mass times velocity, not velocity squared. I.e., that makes recoil a matter of momentum, not kinetic energy.

As an example, I use guns chambered for 223 Remington and 300 Blackout for much of my training. The KE of the 223 ammunition I usually fire is about 1170 foot-pounds, while its power factor, a momentum based value, is 170. On the other hand, the KE of my 300 BLK is ~1090 ft-lb and its PF is ~247. If the KE were the basis of felt recoil, the 223 load would recoil more, but it doesn’t: the 300 produces significantly more felt recoil.

The mass of the powder affects recoil, but in handgun cartridges, it is usually a small percentage of bullet weight. Plus, powder charges tend to be very similar as compared with differences in bullet weight.




“The fundamental cause of trouble in the world today is that the stupid are cocksure while the intelligent are full of doubt.”
— Bertrand Russell
 
Posts: 42220 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
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quote:
Originally posted by randyman:
Physics question - is the felt recoil proportionate to the resulting muzzle energy? Remember, the foot pounds is the calculation of kinetic energy which is 1/2 the mass times the square of the velocity. Not trying to poo-poo on my fellow USPSA members, but power factor is not a true measure of the kinetic energy. For example, a 10% increase in velocity results in a 21% increase in kinetic energy for the same bullet weight.

I won't discuss handgun power factors now, as I am much more familiar with rifles. In my experience with long guns, muzzle energy is a much better predictor of recoil than power factor. Of course, recoil is subjective to the person behind the gun, unless some definitive recoil energy measurement system is used.

Starting with my 16" barrel AR-15:
ADI 69 grain with MV of 2,692 fps. Muzzle energy of 1,111 ft pounds, power factor of 186.
Hornady 55 Vmax with MV of 3,021. ME of 1,115 ft pounds, PF of 166.
Hornady 75 Black with MV of 2,631. ME of 1,153 ft pounds, PF of 197.

I've shoot this rifle a lot, and I don't experience any significant differences in recoil among these loads. They are all about the same in ME -- only a 3% difference low to high. PF says the Hornady 75 has 19% more recoil than Hornady 55 -- I don't experience that.

On to my 300 blackout upper:
ADI 125 grain with MV of 2,046. ME of 1,162 ft pounds, PF of 255.
Hornady 110 Vmax with MV of 2,347. ME of 1,346 ft pounds, PF of 258.

In PF theory, both of these loads are relative thumpers to 223 ammo -- 55% higher than 55 grain and 31% higher than 75 grain. IMO the ADI is a pretty mild load, as it is the slowest of all the 125 grain blackout ammo I've tested. But the ADI 125 is also the most accurate in my rifle, so that's what I use. I would really have to split hairs to say that the ADI 125 recoils more than the Hornady 75. So for me, the ADI 125's PF is totally overstated. The Hornady 110 Vmax is a noticeably hotter load than the ADI 125 -- I feel the higher recoil, also in comparison to my 223 ammo.

Now with Hornady 6.5CM ammo, both ME and PF are a little higher for the 140 grain versus the 120 grain loads. This I agree with.

308 Win makes no sense for PF in my rifle.
FGMM 175 with MV of 2,670. ME of 2,770 ft pounds and PF of 467.
FGMM 168 with MV of 2,734. ME of 2,789 and PF of 459.
Hornady 168 Amax with MV of 2,780. ME of 2,884 and PF of 467.
Corbon 155 with MV of 2,966. ME of 3,090 and PF of 459.
Corbon 190 with MV of 2,693. ME of 3,060 and PF of 511.

I find Hornady 168 to produce slightly more recoil than FGMM loads, but it's splitting hairs. Some people won't feel the difference.

Corbon just flat out loads hot ammo, and Corbon loads produce signs of over pressure in some guns. PF puts the Corbon 155 at less recoil energy than FGMM and Hornady. Bullshit. The recoil from Corbon 155 is noticeably more than Hornady/FGMM and right up there with Corbon 190.

In other words, I don't think much of PF when it comes to my rifles.
 
Posts: 6591 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
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quote:
Originally posted by fritz:

I won't discuss handgun power factors now, as I am much more familiar with rifles. In my experience with long guns, muzzle energy is a much better predictor of recoil than power factor. Of course, recoil is subjective to the person behind the gun, unless some definitive recoil energy measurement system is used.

Starting with my 16" barrel AR-15:
ADI 69 grain with MV of 2,692 fps. Muzzle energy of 1,111 ft pounds, power factor of 186.
Hornady 55 Vmax with MV of 3,021. ME of 1,115 ft pounds, PF of 166.
Hornady 75 Black with MV of 2,631. ME of 1,153 ft pounds, PF of 197.

I've shoot this rifle a lot, and I don't experience any significant differences in recoil among these loads. They are all about the same in ME -- only a 3% difference low to high. PF says the Hornady 75 has 19% more recoil than Hornady 55 -- I don't experience that.



How do you get 19% more recoil from those numbers?
 
Posts: 4964 | Registered: September 13, 2006Reply With QuoteReport This Post
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quote:
Originally posted by sns3guppy:
quote:
Originally posted by fritz:

I won't discuss handgun power factors now, as I am much more familiar with rifles. In my experience with long guns, muzzle energy is a much better predictor of recoil than power factor. Of course, recoil is subjective to the person behind the gun, unless some definitive recoil energy measurement system is used.

Starting with my 16" barrel AR-15:
ADI 69 grain with MV of 2,692 fps. Muzzle energy of 1,111 ft pounds, power factor of 186.
Hornady 55 Vmax with MV of 3,021. ME of 1,115 ft pounds, PF of 166.
Hornady 75 Black with MV of 2,631. ME of 1,153 ft pounds, PF of 197.

I've shoot this rifle a lot, and I don't experience any significant differences in recoil among these loads. They are all about the same in ME -- only a 3% difference low to high. PF says the Hornady 75 has 19% more recoil than Hornady 55 -- I don't experience that.

How do you get 19% more recoil from those numbers?

By comparing PF figures. 197 / 166 = 1.187
I rounded the 18.7% increase to 19%
 
Posts: 6591 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
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There is no valid linear relationship between power factor and recoil, nor should one be inferred. While one my have a power factor of x% more or less than another, power factor does not represent an specific recoil value, nor can such be inferred as a function of power factor change alone.

As previously stated, numerous considerations apply to recoil, particularly "felt" recoil, or perceived recoil.

"Power factor" is nothing more than a competition value mathematically assigned for setting a minimum ammunition standard. It can be indirectly associated with recoil, but as noted in my first post, there are numerous factors to consider.

For a given power factor, increasing bullet weight means a lower velocity and generally speaking, less recoil. The ability to perceive a difference in recoil when the numbers are near one another, however, may prove difficult and will always be subject to multiple factors that will skew the perception.
 
Posts: 4964 | Registered: September 13, 2006Reply With QuoteReport This Post
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The original question was about 9mm loads fired from a handgun, so I decided to examine that question using a more sophisticated recoil calculator here.

One of the unknowns about factory ammunition is the weight of the powder charge, and that has an effect on felt recoil, albeit very minor if they are similar among different loads. I did, however, use approximate values from the Hornady handloading manual for the bullet weights and velocities given in my original post above. For the calculation I used a gun weight of 1.5 pounds that is the approximate weight of a partially loaded Glock 19 (according to the Internet; I don’t have one myself to weigh).

With the below inputs, using the calculator produced the values indicated. (RV - recoil velocity; RE - recoil energy; PF - power factor)

115 gn., 1145 fps, 6.0 gn. powder: RV - 15.4 fps; RE - 5.53 ft-lb; (PF - 132)
124 gn., 1090 fps, 5.5 gn. powder: RV - 15.49 fps; RE - 5.59 ft-lb; (PF - 135)
147 gn., 950 fps, 5.0 gn. powder: RV - 15.68 fps; RE - 5.73 ft-lb; (PF - 140)

Regardless of how the recoil is described it will be very similar for all of the 9mm loads in my example, but not exactly the same. As I indicated in my first post, it will increase slightly with increasing bullet weight in the Blazer factory loads. And as I also stated, the power factors of the loads reflect that progression. For most accurate results a proper recoil calculator should be used, and in the Internet age there is no reason not to, but for similar handgun loads the power factor does permit a quick and rough comparison guide.




“The fundamental cause of trouble in the world today is that the stupid are cocksure while the intelligent are full of doubt.”
— Bertrand Russell
 
Posts: 42220 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
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quote:
Originally posted by sigfreund:
The original question was about 9mm loads fired from a handgun, so I decided to examine that question using a more sophisticated recoil calculator here.

One of the unknowns about factory ammunition is the weight of the powder charge, and that has an effect on felt recoil, albeit very minor if they are similar among different loads. I did, however, use approximate values from the Hornady handloading manual for the bullet weights and velocities given in my original post above. For the calculation I used a gun weight of 1.5 pounds that is the approximate weight of a partially loaded Glock 19 (according to the Internet; I don’t have one myself to weigh).

With the below inputs, using the calculator produced the values indicated. (RV - recoil velocity; RE - recoil energy; PF - power factor)

115 gn., 1145 fps, 6.0 gn. powder: RV - 15.4 fps; RE - 5.53 ft-lb; (PF - 132)
124 gn., 1090 fps, 5.5 gn. powder: RV - 15.49 fps; RE - 5.59 ft-lb; (PF - 135)
147 gn., 950 fps, 5.0 gn. powder: RV - 15.68 fps; RE - 5.73 ft-lb; (PF - 140)

Regardless of how the recoil is described it will be very similar for all of the 9mm loads in my example, but not exactly the same. As I indicated in my first post, it will increase slightly with increasing bullet weight in the Blazer factory loads. And as I also stated, the power factors of the loads reflect that progression. For most accurate results a proper recoil calculator should be used, and in the Internet age there is no reason not to, but for similar handgun loads the power factor does permit a quick and rough comparison guide.


Beat me to it. There are a number of recoil calculators on-line and I was just using one to work up an idea on some heavy .45-70 loads.

I suppose few people would notice a change of .20 ftlb and what might be more demonstrative of felt recoil would be the layout of the gun and how it feels in the hand, bore height above hand web, that sort of thing. In fact, it could be that the layout would have a more dramatic impact on felt recoil person to person due to hold and hand shape differences and for some, if the gun shifts around due to poor hold, rounds of equal recoil impulse might feel differently.

And then we must take into account that the recoil calculator should actually be used to measure the entire spread of "recoils" found in the extreme spread of a shot string using a given load. For example, if a load incorporating a bullet weight of 115 grains produces a low velocity of 1100 and a high velocity of 1200 {100 fps ES} which gives us an average of 1145, then there might be some felt recoil difference over the course of a shot string. 100 isn't a particularly good ES for a load of that type, but my chronographing of ammo over the years would indicate that it could very well occur.

And there is another factor: Gun weight. Gun weight in a high cap pistol changes dramatically as the magazine empties. So in a say, Glock 17 with a 17-round fully topped off mag, the first shot will be fired from a heavier gun than the last. This will impact recoil. And the LOAD will contribute to this difference depending on the different bullet weight used. For example, 115 vs 147 grain bullets means that in a 21 round mag in a SIG P320, the two loads will differ by 672 grains. Will that matter in FELT recoil? Not sure, but it would be a factor to be calculated and in sum with others might result in felt difference in impulse. For example, if the first few rounds of a max-charged, 147 grain loaded 21-shot mag fell on the light end of the ES and the last few rounds fell on the high end of the ES there might be a different amount of felt recoil within the same magazine of ammo.

All interesting and a neat subject for experimentation.


**********************
53 Jesus said to them, “Very truly I tell you, unless you eat the flesh of the Son of Man and drink his blood, you have no life in you.

Read Quod Apostolici Muneris (1878) LEO XIII. This Pope warned us about the Socialists before most folks knew what a Socialist was...
 
Posts: 5055 | Location: Idaho, USA | Registered: May 20, 2005Reply With QuoteReport This Post
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All good points, especially how gun weight and velocity variations can affect felt recoil.

And another thing I first noticed long ago was the difference in how I perceived the recoil of a revolver versus an autoloading pistol. Although I have long gotten over it, the slide reciprocating back over my hand and how that changed the mass distribution of the pistol made it seem like the recoil was significantly greater even as compared with shooting a significantly more powerful cartridge in a revolver.




“The fundamental cause of trouble in the world today is that the stupid are cocksure while the intelligent are full of doubt.”
— Bertrand Russell
 
Posts: 42220 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
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Here's an interesting calculation.

Vel 1100, bullet weight 115 grains, powder weight 5 grains, gun weight 2 pounds:

recoil impulse .67 lbs/sec
recoil vel 10.82 fps
recoil energy 3.64 ftlb

same as above except velocity of bullet 1200 fs:

recoil impulse .72 lbs/sec
recoil velocity 11.64 fps
recoil energy 4.21

now, let's look at adding a loaded mag does to that 1100 fps load...


Recoil Impulse 0.67 lbs/sec
Recoil Velocity 7.73 fps
Recoil Energy 2.6 ftlb

So..........

In theory, we could have the first rounds out of a loaded mag produce recoil in the 2.6 ftlb range and the last in the 4.21 range.

Noticeable?

Maybe so!


**********************
53 Jesus said to them, “Very truly I tell you, unless you eat the flesh of the Son of Man and drink his blood, you have no life in you.

Read Quod Apostolici Muneris (1878) LEO XIII. This Pope warned us about the Socialists before most folks knew what a Socialist was...
 
Posts: 5055 | Location: Idaho, USA | Registered: May 20, 2005Reply With QuoteReport This Post
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If one is concerned with "felt recoil", that is subject to a number of considerations, the principal one being momentum. Newton's 3rd Law indicates that the rearward thrust of the gun is proportional to the momentum of the bullet (and powder charge) leaving the barrel. However, how that force is perceived by the shooter is subject to many other conditions: muzzle flip, motion of the slide, and even the flash and blast of the shot.

flashguy




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Posts: 23912 | Location: Dallas, TX | Registered: May 08, 2006Reply With QuoteReport This Post
Freethinker
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quote:
Originally posted by 3/4Flap:
In theory, we could have the first rounds out of a loaded mag produce recoil in the 2.6 ftlb range and the last in the 4.21 range.

Noticeable?

Maybe so!


That’s something that occurred to me long ago, and you’re the first other person I know of who has ever raised the issue. Looking at some numbers and (approximate!) weights is interesting.

A 17 round magazine load is common these days, and what does the ammunition weigh? That many brass cased 124 grain 9mm cartridges weighs about 3130 grains; if loaded with 147 grain bullets it’s about 3520 grains, or about 8 ounces. A standard full size 9mm P320 with empty 17-round magazine weighs about 807 grams or about 12454 grains. The full load of seventeen 124 grain cartridges adds over 25% to the total.

Compare ammunition weights that can vary from zero to 3520 grains in the magazine to other features that are sometimes considered to have important effects on handling and recoil.

The difference in weights between solid and hollow steel recoil spring guides for the SIG P220 or P226 is about 290 grains, or less than 1/10 of the difference between an empty or fully-loaded 17 round 9mm magazine. A tungsten rod for those guns would cost around $100 and weigh about 3 ounces. That’s well under half of what the full ammunition load weighs, and only about 800 grains (<2 ounces) more than a solid steel rod. Recoil spring guide rods are what we usually hear about someone’s replacing to change felt recoil and handling, and yet their weights are only a fraction of the ammunition’s.

The heaviest common mod I’m familiar with for the P320 these days is the TXG “tungsten infused” grip module that runs about $300. At 16.6 ounces it is far heavier than the standard plastic full size module (~3.7 oz), but it’s still only about twice as heavy as a full magazine load.

It’s obvious that the ammunition whose total weight varies from one shot to the next should have a major effect on the felt recoil and handling of common autoloading pistols, and yet no one ever mentions that.




“The fundamental cause of trouble in the world today is that the stupid are cocksure while the intelligent are full of doubt.”
— Bertrand Russell
 
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