Slow vs Fast, FPE vs FPS.

[Guest]

About Pellets:

https://www.youtube.com/watch?v=OJX3xg1nUAY

About Expansion:

https://www.youtube.com/watch?v=WVjk43NFJAY

Before someone goes off on the arguments he makes WRT caliber remember he lives with a 12 FPE limit on his guns.

 

[fuznut]

Think we all agree accuracy / placement

most important. No one is saying you need

more power to get it done. One area i think

a few might not have a good handel on is

when a projectal passes through. Run a

18 grain pellet through a bird. Now run a 17 grain hmr through a bird. Both pass through

with good placement both kill. With the pellet the bird falls to the ground. With the

hmr tiny bird parts rain down. Velocity matters even in a complete pass through.

 

[Makoda]

17 hmr does not just pass through. Projectile blows apart unlike your jsb pellet. The best an airgunner can do at this point in time is use a hollow point to try and get the most energy dumped in target 

 

[kevinkgb]

Old thread but was reading mid-way through on the topic of cavitation. For cavitation to be effective, the projectile needs to be traveling at high velocities. 5.56 for example is very compatible with a 20" barrel and typically achieves 3,000FPS which allows it to "cavitate" or create a larger wound channel (videos on YouTube on this topic). The bullet at this velocity also has the ability to "fragment" which is when it tears apart inside said target and causes further damage. This is due to the projectile tumbling and eventually falling apart due to high forces acting on it.

As far as I know, there aren't any airguns out there pushing 2,000FPS+. If there was you would get instability in the pellet at longer ranges as pellets aren't made to go faster than the speed of sound (1000fps). But you WOULD get cavitation, and fragmentation at those speeds as it's a lead projectile, not a copper jacketed one and lead typically fragments at slower speeds than fmj rounds. In my opinion, a general rule of thumb is if a projectile can fragment than it is also causing massive cavitation. If you were to use slugs, or FX hybrid slugs you could get those higher velocities and have firearm like qualities of cavitation and accuracy at longer ranges as slugs are more aerodynamically stable. A 2,000 or 3,000 FPS hollow point slug would cause massive cavitation from the velocity, as well as the hollow point design as it would practically explode outward and fragment like a grenade. A normal slug would still cavitate and potentially fragment but less violently. Youtube channel @airarmshuntingsa has a very good video describing how pellets work.

CONCLUSION: In most circumstances with an airgun accuracy trumps over all as pellets don't typically kill by cavitation but by the physical hole they make. If you find yourself an accurate set of hollow point pellets (predator polymags, jsb hades, h&n hornets) use them for soft targets as the pellet will expand making the wound channel bigger, causing more damage. If you're shooting medium to big game animals go for something heavier (for a .25 use 33gr or 44gr) to be able to penetrate the skull or go deeper into tissue to reach vital organs. If you have a monster airgun capable of pushing slugs, or hybrid slugs faster than 950 or 1000FPS+ than use slugs as the wound channel, and flight path will be much better than a pellet. Lastly, if someone out there makes an airgun capable of pushing 2,000FPS+ with pellet or slugs send one my way because I would be VERY eager to use it

 

[Sempaidavid]

Good thread. I'll have to play with velocities and see the outcomes.

 

[N2 Shooter]

Good thread. I'll have to play with velocities and see the outcomes.

As with all things, it depends.

If the projectile expands better at higher velocities, that may be a good objective, if you can still get penetration to or through the vitals. The damage is very dependent on projectile design. I've had great success on avian pest using slugs with a very wide meplat in .25cal. Take a look at this low quality thermal video where I shot a starling in the daytime and literally ripped his entire head off of his body!

It's always good to shoot your ammo into ballistic gel to see how your ammo reacts. Some ammo expands much sooner than other ammo. Take a look at my ballistic gel video intercut with real pest control. In this video, I show slug ammo that flies completely through 16" of ballistic gel fail to drop a groundhog at 30 yards, but a larger groundhog gets anchored by a pellet almost half the weight.

 

[kevinkgb]

As with all things, it depends.

If the projectile expands better at higher velocities, that may be a good objective, if you can still get penetration to or through the vitals. The damage is very dependent on projectile design. I've had great success on avian pest using slugs with a very wide meplat in .25cal. Take a look at this low quality thermal video where I shot a starling in the daytime and literally ripped his entire head off of his body!

It's always good to shoot your ammo into ballistic gel to see how your ammo reacts. Some ammo expands much sooner than other ammo. Take a look at my ballistic gel video intercut with real pest control. In this video, I show slug ammo that flies completely through 16" of ballistic gel fail to drop a groundhog at 30 yards, but a larger groundhog gets anchored by a pellet almost half the weight.

Your video is great as the things I mentioned can be seen here. There's some ammo that isn't going fast enough to cause "firearm" like cavitation. Then there's some pellets that are capable of expanding because they were designed for slower velocities that cause expansion. OVERALL everyone's goal is to get that projectile going as fast as possible and shooting the right slugs in order to get MAX damage and accuracy. There's a video by @upnorthairguns shooting FX Hybrids and they practically explode whenever they hit soft targets (meat). Imagine if they were going faster

If your gun cant shoot slugs (either the FPS is not fast enough, or your barrel is not suited for them) then you can start cherry picking what pellets are 1) most accurate 2) most lethal (expandable). Not all guns shoot polymags or slugs. If the choice comes down to just using JSB Diabolo's use whichever ones most accurate as you wont be causing a ton of cavitation anyways.

You can go a step further and shoot into gel to see which one cavitates the most out of a heavy or standard pellet but don't expect 5.56 NATO FMJ cavitation

 

[karl_h]

@N2 Shooter , your gel block is just showing what is in flesh a temporary wound cavity, real flesh at such slow speeds stretches and springs back with no damage. Lots of research on that out there, not hearsay. @kevinkgb has it right with the roughly 2000 fps and maybe as low as 1800 fps needed to create permanent damage from hydrostatic shock, lots of research out there backing it up. Temporary stretching does no permanent damage, I have lots of experience cleaning deer I shot with low velocity rounds in 40 years, and without fail everyone backs that up.

Beginnig in the late 70's, I spent the first 10 years of deer hunting with handguns, started with a 38 special loaded with 158 grain hard cast semi-wadcutters @850 fps. Clean fast kills on all the ones I shot with it, all broadside lung shot all good short blood trails. Finally found an older 60's S&W 357 worth buying and in developing a load for it, I came up with a stupid accurate light load with the same 158 gr bullet at 1100 fps, and a good load at 1380 fps. Out of more than a dozen with the 38 special and more than that with the 357 at 1100 fps there was absolutely no difference in damage to lungs on deer when dressing them out, and I looked. The few times I used the hotter load in the 357, there may have been the tiniest increase in damage to the lungs. I mean tiny, without having two side by side may just have been imagination/hope/belief there was a difference. Rounds are just too slow, temporary wound cavity is just that, a little stretching as bullet goes through that springs back with no damage, better to have a wadcutter actually cut .

Expanding bullets at slow speeds only accomplish a slightly bigger internal hole, with smaller entry/exit due to stretching to break through hide rather than cutting. I shot a few with the 357, but not many, much preferred the semi wadcutter for the clean cut hole, better blood trails. Only "benefit" of the expanding was minimal greater size hole through lungs from expansion. Nothing beats the cookie cutter entrance hole a wadcutter or semi wadcutter makes, it never closes up from the hide stretching and springing back without being cut, and often makes the same cookie cutter hole exiting, but sometimes bullet gets upset and you don't get that on exit.

I shot a deer a couple years ago with a 130gr varmint bullet meant for high power rifles out of a 300 blackout, at 2080 fps muzzle velocity that bullet doesn't blow up like it was designed to do at 308 and up velocities, just expands into perfect mushroom and is ungodly accurate in my blackout, I had to try. At the distance I shot the deer at, impact was no more than 1800 fps. The entry and exit holes were tiny, with the exit being bigger than the entry but still less than .308 diameter due to stretching of the hide as bullet passed through. Internally, the lungs had nearly a 1/2 inch hole through them, as did the rib meat on entrance side, bullet went perfectly between 2 ribs on entrance and had expanded already pushing through the hide. No bloodshot meat/lungs/anything, as no hydrostatic shock, round was too slow when it got there. Due to the small size of the entry/exit I never used it on a deer again and won't, even though that deer went maybe 17 yards, not a drop of blood on ground until it fell. With the small entry/exit, I'm sure if I had to track it I would be looking for spray from it's mouth as it was running, doubt any would come out the holes before it expired.

 

[Airgunmann]

Big and slow is better in the world of air guns like shooting handguns there isn't the shock like there is with a rifle its more like muzzle loader need a larger pellet or bullet to create a larger wound channel and a good placed shot as well

 

[JimD]

Our airguns make holes. The caliber, fpe and pellet design helps to determine how deep and how wide the hole is. Where we put the hole is by far the most important but how deep and how wide the hole is also makes some difference. I regularly use my P35s for squirrels and other small game. The 177 is about 19 fpe, the 22 and the 25 are about 32 fpe (25 is detuned because it likes 20 grain FTTs). I've also taken 15 with my Prod, my first PCP mainly with a 18 fpe tune abut also a few with the original 13-14 fpe tune. With the low power tune, body shots were a bit iffy. With the 177 a couple squirrels were not dead when they hit the ground but died quickly. With the higher powered 22 and 25, the pellets almost always go through and the squirrels have always dropped quickly. The only two that ran at all were hit with the 25 right in the middle of the chest from the front. The pellet was found under the hide in the back of the squirrel. Furthest they went was about 15 feet. All shots were with pellets that did not expand.

The Prod is the lowest velocity, it can only push the copper plated FTTs it likes to about 750 fps. But it certainly doesn't drop squirrels or other game more quickly than the others. It is completely adequate and comparable to the 177 which is pushing it's Baracuda Match pellets to about 900 fps. Both work very well with good shot placement. Neither will shoot through a squirrel on most shots. If you hit a substantial bone they don't exit. But the hole will go through a shoulder if you hit it and chest shots from the side normally drop squirrels quite nicely.

The 32 fpe airguns almost always exit and I think it helps. Two holes bleed quicker than one and letting a lot of air into the animals chest will prevent the lungs from working. But I also see switching to an expanding pellet for guns with plenty of power to be a reasonable choice. A wider hole through the vitals should kill quicker. But I would only use an expanding pellet in a gun that is very likely to go through with a domed pellet. You will lose a lot of penetration to get expansion and you still need enough penetration to get to the vitals even when you smash a shoulder.

Energy dump is nonsense. I've hit a 4 ounce squirrel with a 42 fpe 25 caliber pellet. I hit it in the head and it was DRT but it didn't fly backwards are anything. The squirrels hit with my P35 in 25 caliber that ran absorbed all the energy left in pellet which started at about 875 fps and thus about 32 fpe. They still ran. Not because the vitals were not hit but probably because both lungs were not hit. They were dead but it took them a few seconds to figure that out. Sideways through the chest with the same guns has not resulted in any runners. All were DRT.

Hits in the right place kill well as long as the pellet penetrates far enough to hit the vitals. Through the chest or into the brain. With lower powered airguns, my experience is they may run a little with chest hits. But not very far. But if you place the pellet in the intestines, the squirrel will die but not before running a long ways and you are unlikely to find it. Doesn't matter how many fpe you had or that you used a super duper expanding slug. I think I get more DRT results with a little more fpe but I can't imagine needing (or even wanting) more than low 30s fpe for a squirrel. Maybe if you shoot at much longer range like with ground squirrels. But not for tree squirrels. Large diameter holes in the wrong place just don't kill very well.

 

[N2 Shooter]

Let's not confuse knockdown power with hydrostatic shock. They are not the same thing.

Hydrostatic shock is well known and happens when there is stretching of body tissue at such a rapid rate and quantity that it tears. Knockdown power is the disabling effects of a round that are secondary and tertiary to any terminal damage by the round.

You do not have to cause visible damage to plant prey right where they were shot. Disruption of the nervous and respiratory system does not mean you blow a groundhogs lungs out of its body . If a projectile expands and does not completely exit game, the energy that remains after the hide is penetrated and the round traverses until rest is transferred to the animal, this is just plain physics.

Ever hit a funny bone? Ever catch a blow to the solar plexus during football in high school or college? Ever catch a left hook to the liver in amature boxing or karate? Did it kill you (I hope not), but it put you down on the spot, and in a few minutes you recovered to sit out a few plays, or as the rules have it now, the rest of the game/round/match/ blah, blah, blah.

Now couple this temporary incapacitation with a wound that has you bleeding out. You will have all of the instant effects of the temporary trama, but you will not recover. The clock is about to run out on you.

If a round hits game at 900fps and doesn't leave it's body, is the same as it getting hit at over 600mph. If that temporary expansion cavity pushes into the liver, that is enough to incapacitate game, while it succumbs to blood loss.

I hope I have clarified my stance on this. Our ammo speeds don't produce hydrostatic shock, full stop. But ammo selection and design can deliver debilitating effects that are not terminal, but can anchor prey while they bleed out.

 

[Firewalker]

Let's not confuse knockdown power with hydrostatic shock. They are not the same thing.

Hydrostatic shock is well known and happens when there is stretching of body tissue at such a rapid rate and quantity that it tears. Knockdown power is the disabling effects of a round that are secondary and tertiary to any terminal damage by the round.

You do not have to cause visible damage to plant prey right where they were shot. Disruption of the nervous and respiratory system does not mean you blow a groundhogs lungs out of its body . If a projectile expands and does not completely exit game, the energy that remains after the hide is penetrated and the round traverses until rest is transferred to the animal, this is just plain physics.

Ever hit a funny bone? Ever catch a blow to the solar plexus during football in high school or college? Ever catch a left hook to the liver in amature boxing or karate? Did it kill you (I hope not), but it put you down on the spot, and in a few minutes you recovered to sit out a few plays, or as the rules have it now, the rest of the game/round/match/ blah, blah, blah.

Now couple this temporary incapacitation with a wound that has you bleeding out. You will have all of the instant effects of the temporary trama, but you will not recover. The clock is about to run out on you.

If a round hits game at 900fps and doesn't leave it's body, is the same as it getting hit at over 600mph. If that temporary expansion cavity pushes into the liver, that is enough to incapacitate game, while it succumbs to blood loss.

I hope I have clarified my stance on this. Our ammo speeds don't produce hydrostatic shock, full stop. But ammo selection and design can deliver debilitating effects that are not terminal, but can anchor prey while they bleed out.

If you say so...

 

[N2 Shooter]

If you say so... View attachment 370528

This is always a good one to see!

When you put a round into the cranium, it causes a pressure wave as the skull takes the impact. What happens here is that pressure certainly would like to go somewhere, and those two nice pressure relief valves called eyeballs will let that pressure out faster than any other means!

But hydrostatic shock is talking about the expansion of soft tissue. Even this hit with 160fpe did not cause secondary tissue damage, but it certainly rippled the fat on this chonker and put him down definitively.

 

[Firewalker]

"Hydrostatic shock is the controversial concept that a penetrating projectile (such as a bullet) can produce a pressure wave that causes "remote neural damage", "subtle damage in neural tissues" and "rapid incapacitating effects" in living targets."

Yupper, it definitely caused a LOT of secondary tissue damage.