Final formula for obtaining the Hunting Energy Units on Air Rifles.

Jump to latest Follow Reply
Emu

Emu

Member
Jan 15, 2020
3,600
2,318
Queretaro, Mexico
Taking into consideration:

a) That in Air Rifles (as it is when hunting with a bow and arrow) the killing power is related with size of damage (cut-hole) caused in vital tissues;

b) That the damaged caused is related by a combinations of velocity (fps), weight (grains), diameter, density (expansion and resistance to hard tissue) and shape that facilitates penetration of the pellet/ slug.

c) Not all previous factors are taken into consideration when making calculations of foot pounds, and therefore, foot pounds are not related with size of damage on tissue, and then not necessarilly are usefull for getting to know efectiveness for hunting purposes.

There are of course a lot of factors that could get influence on an effective shot. The main one is shot placement. So the utility of the calculations would be considering exactly the same point of impact on the same kind of hunting and, at the exact fps on the formula (what at the moment of the impact is almost impossible to be precisely meassured).

We only are able to meassure the speed of the pellet/slug at the exit from the barrell. Then we should take that measure.

Taking into consideration all the above explained, the following is the formula that, in my opinion, should be taken in regard of Air Rifles hunting power, because it includes all the meassurable variables that have influence and that we know of the projectile. Those are (speed, weight, diameter, density and shape (that cause resistance to penetration):


Screenshot_20220816-170621.png
 
Last edited:
  • Like
Reactions: kirkb
Where did you get your formula and have you done a units check?
Click to expand...

I worked a lot in formula trying to incorporate all the meassurable aspects available.

What you see is far from being the first try. I Made a lot of runs to correct the inconsistencies found on previous versions of such formula.

I do not understand what you mean for "units check", could you please explain to see if I can give an answer?


 
Upvote 0
Enrique, I think you have way too much time on your hands! Since all the projectiles are of similar design and material, I think the fpe generated by each is probably a legitimate determining factor. That said, the numbers aren't worth a can of warm spit if the shot isn't placed properly. I appreciate your work, but I'm not sure of its practical application.
 
Upvote 0
Look at what "swopever" wrote in the following chat:

https://www.airgunnation.com/topic/25cal-why-or-why-not/?view=all

What he observed is consistent with the postulate behind the formula.

At the end the main idea was to answer the following question:

Considering you have three air rifles, a .22, a .25 and a .30 all of them shooting at the same 55 foot pounds of energy, could you say that for hunting purposes the three are the same?

Trying to answer that question, the exercise gave the answer that the lethality of the three calibers are far away from being the same.

That's it.
 
  • Like
Reactions: 3Crows
Upvote 0
The comparison to which you refer is a slug vs pellet, two very different projectiles. A critical variable, how much energy is transferred to the target? Still not as important as shot placement, but other things equal (and they never are), it is more important than fpe generated. Consider two drag race cars, one with 100 less hp, but able to transmit it to the pavement with minimal wheel spin, while the more powerful car wastes the power in tire smoke. Some CF cartridges of modest power gave gained a reputation for lethality beyond their power level. Maybe that is because they put a much greater percentage in the target. 
 
Upvote 0
The comparison to which you refer is a slug vs pellet, two very different projectiles. A critical variable, how much energy is transferred to the target? Still not as important as shot placement, but other things equal (and they never are), it is more important than fpe generated. Consider two drag race cars, one with 100 less hp, but able to transmit it to the pavement with minimal wheel spin, while the more powerful car wastes the power in tire smoke. Some CF cartridges of modest power gave gained a reputation for lethality beyond their power level. Maybe that is because they put a much greater percentage in the target.
Click to expand...

Read again.

He privilege the caliber over the kind of projectile.
 
Upvote 0
I've read it again, still don't follow you. No matter, it's an academic discussion that has no end. I expect there is one thing on which we would see universal agreement, a head shot with at a 12 fpe .177 is instantly fatal, and a gut shot with a 45 fpe .25 is a messy cripple.
Click to expand...

If you read the very first comment of this chat it says that the consideration is about exactly same placement, to same animal, same angle, bla, bla,bla.

So the discussion could appear theoretical but it has a very practical effect for hunting purposes.


 
Upvote 0
Hi 

HEU

A very imo useful addition for hunting.

Yes accurate shot placement and knowledge of your quarry is extremely important.

Think HUE explains perfectly stopping power.

No one likes to see quarry run for x yards before dropping. When hunting potentially dangerous wounded animals in heavy brush good luck with your “high power small calibre”

So stopping power imo is everything and HEU gives an insight .

Some countries do not allow smaller calibre , lesser stopping power or HEU, to be used on bigger quarry for that reason.

Yes a .177 will kill . 

Years ago a famous hunter wrote a book” use enough gun “.

Slightly off topic but relevant

In the Falklands war UK special forces came across a hut occupied by the enemy . This zone was needed for resupply , men equipment etc.

A plan was made to take out the occupants,( about 5 guys heavily armed ). 
The SF group was 4 men , 3 armed with rapid fire small calibre rifles and 1 with a 7.62 . The enemy burst out of the hut, 2 or 3 were hit quickly arms legs etc but were still dangerous. The 7.62 put them down and shock effect was huge. The SF guys were lucky.

Stopping power!

I am convinced for hunting purposes with less chance of “runners” that maxim “use enough gun” is priime.

So FPE for target shootng but HEU does clearly show the difference between calibres.

safe shooting 


 
Upvote 0
I've read it again, still don't follow you. No matter, it's an academic discussion that has no end. I expect there is one thing on which we would see universal agreement, a head shot with at a 12 fpe .177 is instantly fatal, and a gut shot with a 45 fpe .25 is a messy cripple.
Click to expand...

If you read the very first comment of this chat it says that the consideration is about exactly same placement, to same animal, same angle, bla, bla,bla.

So the discussion could appear theoretical but it has a very practical effect for hunting purposes.

Click to expand...


You're trying to use anecdotal evidence, from several uncontrolled situation to prove your theory?

" Without doubt the .25 put down squirrels with more authority. Body shots were still clean kills with .25" - were ALL shots taken from the same distance? Doubtful

Were all shots in the exact same spot in the "body"? The same angle? Were all the squirrels the same sex? Age? Was a comparison done on the tissues post mortem?

Without answers to the above this "evidence" means nothing. And to me, someone who would try to use such "evidence" to prove their "theory" is suspect.
 
  • Like
Reactions: Glem.Chally
Upvote 0
I've been involved in hunting and the shooting sports for over a half century. Call it what you want, power, energy, killing power, stopping power, shock,etc., the discussion never ends. It can be of academic interest, and certainly is a topic of interesting discussion. But in practice, I believe the topic is so simple it needs no more due diligence. I can think of no animal I might shoot, about which there is not an abundance of experience readily available on which to draw. Obviously, some sources are more trustworthy than others, something usually easy to determine. Over years of hunting, all the variables mentioned above, and a myriad of others not mentioned, have come together to form that magical word, "experience". And there are those among us who possess it. Robert Ruark said, "use enough gun". If in doubt, too much is better than too little, since we are talking about the humane killing of an animal. I wish the best for the further development of the HEU concept, I'll read it with interest. But, if I'm going to hunt a new critter with an air rifle, I'll be talking to some folks, not reading a chart. 
 
  • Like
Reactions: thumper
Upvote 0
I have a spreadsheet where I calculate the Taylor knockout factor and something else that slips my mind right now in addition to fpe. But I don't think the other factors tell us more than the fpe. If what we want to know is how reliably a gun/tune will kill we need to know how wide a hole and how deep a hole it will make. Formulas don't give us any sort of absolute answer on this. I like to test in wet paper, these days I use old magazines. Some may use ballistic gel or soap. As long as you can cross reference your test material to your quarry I doubt it matters what you test in. I tested penetration of my Prod with a couple different tunes and several projectiles in dead squirrels. That gives me a rough idea how many pages penetration in wet paper translates into through penetration from the side on a squirrel. I had to increase the fpe of my Prod to get through penetration and when I did, I got no more squirrels running off after a body shot. Pellets rarely pass through with Prod shots because they normally go through at an angle, or hit the skull or front leg bones. But they do deep enough to reliably kill with decent shot placement.

Shot placement is #1, then enough penetration to reach the vitals, then wider holes kill quicker. I am not a fan of expanding projectiles in airguns but if you have enough penetration with them, the wider hole should kill quicker. My issues are I haven't found any that are as accurate in my guns as simple domed pellets and they dramatically reduce penetration in my tests. At least a couple of my guns would still have adequate penetration but they also drop squirrels well with simple domed pellets. So I occasionally test another expanding projectile but I use domed pellets.
 
  • Like
Reactions: mtnGhost
Upvote 0
JimD said:
I have a spreadsheet where I calculate the Taylor knockout factor and something else that slips my mind right now in addition to fpe. But I don't think the other factors tell us more than the fpe. If what we want to know is how reliably a gun/tune will kill we need to know how wide a hole and how deep a hole it will make. Formulas don't give us any sort of absolute answer on this. I like to test in wet paper, these days I use old magazines. Some may use ballistic gel or soap. As long as you can cross reference your test material to your quarry I doubt it matters what you test in. I tested penetration of my Prod with a couple different tunes and several projectiles in dead squirrels. That gives me a rough idea how many pages penetration in wet paper translates into through penetration from the side on a squirrel. I had to increase the fpe of my Prod to get through penetration and when I did, I got no more squirrels running off after a body shot. Pellets rarely pass through with Prod shots because they normally go through at an angle, or hit the skull or front leg bones. But they do deep enough to reliably kill with decent shot placement.

Shot placement is #1, then enough penetration to reach the vitals, then wider holes kill quicker. I am not a fan of expanding projectiles in airguns but if you have enough penetration with them, the wider hole should kill quicker. My issues are I haven't found any that are as accurate in my guns as simple domed pellets and they dramatically reduce penetration in my tests. At least a couple of my guns would still have adequate penetration but they also drop squirrels well with simple domed pellets. So I occasionally test another expanding projectile but I use domed pellets.
Click to expand...
"Shot placement is #1, then enough penetration to reach the vitals, then wider holes kill quicker. I am not a fan of expanding projectiles in airguns but if you have enough penetration with them, the wider hole should kill quicker. "

Absolutely agree!

I have confirmed that JSB Hades in.30 Cal are extremely effective on chest shots on coyotes.

But what you say is the key: Shot placement, enough penetration to get to vitals and wider hole to cause more damage on tissue. That is the name f the game to get cleaner and faster kills.
 
Upvote 0
You must log in or register to reply here.
Top Bottom
Back
Home
Forums
Resources
Menu