Slow vs Fast, FPE vs FPS.

FPE may be deceptive for kill power. High energy (High Speed) might just allow the pellet to pass through the bird without dumping the energy needed to dispatch the bird. The lower speed / energy might allow the pellet to enter, dump energy and improve the kill potential. Seems counter intuitive, but might be the case?

I believe Saltlake58 went right to the heart of it. I'm sure the birds that fly off also die because of your shot placement but probably from a combination of shock and blood loss which could be slower. Someone with more technical smarts then myself needs to chime in on this.

As the projectile passes through the target,it still possesses a certain amount of the energy imparted to it upon firing. When a projectile is held captive by the targeted object,All energy which was initially tranferred to said projectile by the onset of its motion has been absorbed by the targeted object.

I tested this theory to a degree by placing my wifes good dishes on a table with a tablecloth underneath them. A *quick* pull of the tablecloth resulted in the dishes remaining on the table,Nearly in the same spots.

I then repeated the process but I tried removing the tablecloth Slowly. This resulted in an Incredible amount of damage. The initial damage was transferred directly to said dishes. There was also a large amount of energy imparted directly to my ass after a very short delay.

These are my theories and results from experimentation in controlled conditions. Others are encouraged to chime in with their ideas and findings.

Hope this helps to bring some light to this matter.

Mike.

I also agree with Saltlake58. Also don't forget that cavitation plays an important part.

As the projectile passes through the target,it still possesses a certain amount of the energy imparted to it upon firing. When a projectile is held captive by the targeted object,All energy which was initially tranferred to said projectile by the onset of its motion has been absorbed by the targeted object.

I tested this theory to a degree by placing my wifes good dishes on a table with a tablecloth underneath them. A *quick* pull of the tablecloth resulted in the dishes remaining on the table,Nearly in the same spots.

I then repeated the process but I tried removing the tablecloth Slowly. This resulted in an Incredible amount of damage. The initial damage was transferred directly to said dishes. There was also a large amount of energy imparted directly to my ass after a very short delay.

These are my theories and results from experimentation in controlled conditions. Others are encouraged to chime in with their ideas and findings.

Hope this helps to bring some light to this matter.

Mike.

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LOL, I think you're spot on Mike!

Agree. Have you tried hollowpoint or Predator ploymag pellets. They may be different. 

I've had the same issue before. 80fpe .30 had problems with birds dying instantly and I mean dead through the center huge whole. Yet a .22 at 860fps will drop them almost always. I think too fast doesn't help unless it's a hollowpoint

I also agree with Saltlake58. Also don't forget that cavitation plays an important part.

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Speed causes cavitation.

I have never bought into the whole energy dumping theory. The way I see it is it doesnt matter if the projectile passes thru or stops inside as far as energy deposited goes. A pellet hitting a bird at 50 fpe hits the bird with 50 fpe regardless of exiting or not. The tissue inside the bird will have that force exerted upon it if it stops just short of penetration or if it passes completely thru. A pellet hitting a bird at 35 fpe hits the bird with 35 fpe and the tissue/organs still only sees 35 fpe worth of energy regardless of stopping inside or over penetrating. You dont magically gain energy because the pellet stops. I know you will say but it dumped all its energy into the target. Ok well the pellet does not create more energy and if it is passing thru tissue with 35 fpe of energy then stops the tissue has been impacted by 35 fpe and less along the wound channel correct? Well that same pellet passing thru tissue at 50 fpe is doing the same thing. The big difference is that the 50 fpe pellet deposits its energy thru more tissue due to traveling completely thru the animal. Heres another point to look at is the 35 fpe pellet stops inside the animal so the pellet is losing energy fast enough as it passes thru the animal that it stops instead of penetrating. The tissue damage in the area of the slower moving pellet will have less cavitation which will mean less tissue damage and the slower the pellet gets the less damage you will see in the wound channel. On the other hand the 50 fpe pellet still carries enough energy to completely pass thru causing more tissue damage due to higher energy levels being passed onto the tissue.

Theres many other things to consider than what I posted above as far as if there is enough or fairly equal tissue damage but I was explaining my theory as to why over penetration doesnt dump less energy than less than complete penetration.

If the 35 fpe pellet passes thru both lungs and causes permanent damage/ cavitation and stops at that point the bird is dying quickly and the same is to be expected with the higher fpe as it passes completely thru the animal.

Sometimes I wonder if the pellet being stuck inside the birds cavity some how causes longer disruption to its body functioning. Imagine having something the size of a pellet stuck in your body. I am sure that can cause pressure to the central nervous system if the pellet is in the correct place or other important functions depending on location. So if thats true then a pellet resting close to the spinal column may cause the bird to be paralyzed resulting in the hit bird folding up and just dropping. If you hit that bird in the exact same spot but dont clip the spinal column and the pellet flies thru its still mobile until it bleeds out. Just some thoughts that ramble thru my brain sometimes.

From experience I know hitting a bird in the right spot with anything from 6 fpe to 50 fpe folds them right up with no fly offs. I wont argue that or even entertain the idea that anything less than that will happen. I have shot way to many birds, Squirrels and other critters to know that to be complete fact. You see posts from experienced shooters talking about fly offs and knowing they put the pellet in the right spot so something about the fpe had to be the reason. I think the real answer is probably deflection. The pellet may have started out contacting exactly where it was suppose to but the heavier veins in the feathers caused the pellet to deflect and hit a less than perfect spot. Nothing you can do about that one you just live with the fact things happen that you cant control. 

I think that there are a few factors that come into play here, not just dumping of energy etc. 

For example: say I shoot a squirrel at 20 yards right between the eye and ear with a .177 out of an HW30 (5-7fpe) then take the same shot with a .25 PCP, that squirrel is going nowhere in either case. 

I have shot a squirrel many a time with a .22 18gr diabolo at 900fps, complete pass through the chest, and it has just dropped dead instantly. Hitting the heart, vs hitting just lungs, makes all the difference. 

So, as always, it’s shot placement. Heart, Brain, or Spine shots. BUT...speed may make the difference when shooting something a bit more dense, say, a hog’s cranium. 

Just my thoughts. 

If I am going for head shots on grey squirrels then I use an dome pellet which tend to be more accurate at longer distances. A brain shot that passes through does not matter. If going for chest shots then I want expansion and energy dump and use hollow points. Of course with hollow points you need the velocity and game resistance to make them expand. Look at this video I did shooting apples with my FX Streamline .22 cal.at about 35 yards. On some apples I was using the JSB 18.13 dome pellets and other the H&N Terminators 16.36 grain The apple shooting begins at about 2:45 min in the video. See what you think about the results. Bill

https://www.youtube.com/watch?v=IKiwlkWlwOc&ab_channel=GunPowder%26AirPower

Here is a perfect fresh example. I shot this squirrel at about 20 yards with my .177 LGV Master Pro using the 10.34 grain JSB Diabolo. Aimed for the heart, but I misjudged the shot and hit just above, most likely hitting the spine. Matter of fact, I thought I had missed it all together, but then it dropped from the tree, spasmed a few seconds and died. The pellet went through and through traveling at about 710 fps (if I recall correctly) 

Energy (E) is a function of mass (m) and speed (v): E = 0.5 m * v^2. You get quadratic increase energy with linear increase in speed. I do think you have to factor (subtract) energy loss via pass-through. My guess is minimum energy required for pass-through is interesting, but I don't know if or how energy dumped in target (e_t) is dependent on energy of pellet (e) on a pass-through. Or said different, if you require 5 FPE for pass-through, is e_t fixed if you hit it with 5, 10, or 50 FPE? You probably have to assume identical pellet deformation.

Ballistic coefficient plays a part in energy transfer. A long skinny projectile will slip through the air (and through a target) more efficient than a short, wide projectile.



I tried the HN pile-driver pellets, and found that they will punch neat pencil holes through the animal, transferring little energy compared to a hollow point slug or even a diabolo pelllet. Yes, the target dies from the pencil hole, but not nearly as quickly or neatly as when hit by a flying ash tray.



A hit on the "off switch" is a kill. The greater the area affected by the projo, be it by FPE transferred or by caliber, the greater the impact on the off switch. Pellet or slug expansion and post bone contact performance is the benefit of high FPE. High FPE on a non-expanding bullet/slug/pellet results in a small wound.

Ballistic coefficient plays a part in energy transfer. A long skinny projectile will slip through the air (and through a target) more efficient than a short, wide projectile.



I tried the HN pile-driver pellets, and found that they will punch neat pencil holes through the animal, transferring little energy compared to a hollow point slug or even a diabolo pelllet. Yes, the target dies from the pencil hole, but not nearly as quickly or neatly as when hit by a flying ash tray.



A hit on the "off switch" is a kill.  The greater the area affected by the projo, be it by FPE transferred or by caliber, the greater the impact on the off switch.  Pellet or slug expansion and post bone contact performance is the benefit of high FPE. High FPE on a non-expanding bullet/slug/pellet results in a small wound.

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This is true. If you compare domed pellets to domed pellets and same caliber and weight the pellet with the most fpe will cause the most damage no matter if it exits or not. The slower one could penetrate half way thru the vitals and the faster one can stop just under the skin and the faster pellet will have caused more damage. Its not as cut and dry once you start comparing different calibers and projectile weights against each other since there are more factors involved. But no matter the projectile the faster it hits the target the more energy its going to impart on the target resulting in larger amounts of tissue damage.

As far as high fpe with non expanding pellets creating small wounds goes I would argue low fpe on non expanding pellets creates even smaller wounds. The laws of physics prove that. If the pellet will not expand it will still create a larger wound channel than if its pushed slower. The faster the pellet is pushed thru tissue the more cavitation it will cause resulting in larger amounts of tissue damage from the fluid being displaced by the front of the pellet. So if you are stuck using non expanding projectiles like most airgun hunters your next best thing is either caliber size increase for more frontal area or higher velocity to generate more fpe. 

I have to say that I have more effective bird kills at up to 50 yards with an 8fpe 675fps 1701P than a 16fpe 900fps 177 Marauder using the same ammo. The same held true with a 177 R7 vs 177 R9 a closer range.

Dropped them stone cold with the lower power. Shot of course under calm conditions.



CA

Been argued about sence the first caveman

chunked a rock. More is better! If you have

energy to spare look for the design that will

hit hardest and dump the most power in to

target. More energy gives you more options

for a leathal shot. Just one knuckel draggers opinion.

I guess looking at ballistics gel might provide a visual. Most higher powered guns will get anywhere from 8 to 12 or more inches of penetration. The cavity really opens up a couple inches in and the pellet might even spin a bit, dumping more energy.

Problem is that the bird only represents the first two inches of the gel. Yes, the bird will bleed out and your shot is successful, but the bulk of the energy passes right through.

Change from a high powered gun to a 12 fpe type gun. Pellet will still penetrate a couple inches, and for a bird, that's all that really matters. In the end, the bird is dead, so probably doesn't make much difference.

Change game from bird to rabbit, and suddenly, the higher powered pellet starts to make more sense.

The knuckle dragger above is quite correct, more power does give more options, but there are times when lower power is just enough.

In the end, as long as the prey is dispatched quickly, it doesn't matter

Use the old turkey standard of 2fpe to penetrate the neck or skull and you can see we all are over penetrating at normal ranges. Pellets don't give shock like a high powered rifle does, I think some think so but my results don't show it. I don't shoot jelly or phone books or whatever else you want to test pellets or PB bullets into. I see what happens in the field, energy is pushing your pellet thru the target. The harder the target in my case bone, the more energy you need. Pellets require shot placement, the larger the game the more critical this is. Gut shoot a sparrow with a .22 cal and it's dead, do that on a woodchuck and it probably will die but it wont be quick or humane. The slow vs fast debate when feathers are involved is moot, refer to turkey statement above. It's the joke my buddy and I say, what level of dead are you shooting today. Just my 2cents from a hunter. Save the jelly for your kids. 

Most American air gunners think they need way more power than they really need to humanely kill small game and pests. Hookster pellets do create shock but most of the time its not as dramatic as a 4,000 fps 55 gr. varmint bullet when it smacks into a prairie dog. Take a .25 cal 25 gr. JSB and push it to 40+ fpe and smack a house sparrow with it. The house sparrow will be turned inside out. It takes a gross amount of over power to get that effect but it illustrates that pellets can cause shock. Some people think you need big fpe from a pellet in order to have humane kills and thats the biggest misconception. The truth is you dont kill with raw power when using airguns for hunting/ pesting you humanely kill by putting the pellet in the correct spot of the vitals nothing more nothing less. They have been killing small game across the pond easily for decades with sub 12 fpe so the argument of needing more power doesnt hold water.