Best Cal for hunting supposing same foot pounds energy.

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Emu

Emu

Member
Jan 15, 2020
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Queretaro, Mexico
Hi,

Supposing you have three rifles that all of them shoot at 55 foot pounds of energy, one is a .22, the second a .25 and the third is a .30 Cal, and you want to hunt a medium size animal, the question is: which one would be better taking into consideration that all have the same energy?

All the three shots are accurately placed, so no discussion about accuracy.

Possible answers:

a) Same energy, same damage to vitals. Then .22, .25. and .30 are the same.

b) More speed more penetration more damage to vitals. Then .22 is better

c) More mass more damage to vitals. Then .30 is better.

d) Optimal would be a combination of speed and mass. Then .25 is better.

Maybe those who have made tests with ballistic gel may tell us, so we or at least me, can learn.

Thanks.
 
Enrique, 😊



you might be interested in this 5-part series of articles about killing game and projectile choices.

The link is to the first article, links to the others are there, too.

Two links are for expansion and penetration tests for slugs and for pellets:

https://www.airgunnation.com/topic/%f0%9f%92%80-quarry-what-killsem-dead-the-mechanics-of-killing





There are a lot of factors to consider than just caliber and power and weight.



🔶For example: If you're shooting long ranges, say beyond 80y (73m), the projectiles that have a high BC will have much more energy left than those with a low BC.

▪Pellets generally have much lower BC's than slugs.

▪Pellets of a smaller caliber have a usually a higher BC than pellets of a larger caliber — if they weigh the same (➔ they have a higher sectional density) and if they have a similar shape (form factor).

▪Hollow point pellets have a much lower BC than domed pellets (if caliber and weight are the same).

▪Hollow point pellets crush a larger amount of tissue and make a larger permanent wound cavity. The also do not penetrate as far as a domed pellet.

Of course, with enough energy, both will penetrate far enough.

HP pellets (and slugs) need a fairly high impact velocity in order to expand (800fps is good, 700fps can work with some HP pellets, cf. the test results in the articles linked above).





🔶Larger caliber projectiles (non-expanding) make larger permanent holes into game. More tissue crushed, more blood loss. Quicker death. Good! 😊

However, we'd like to have enough impact energy that these projectiles reach the vitals....



🔶If you try to crack hard skulls you'd need a hard projectile (hard lead), and a fast impact velocity — to overcome the threshhold of the bone that wants to simply flex instead of break.

Even more so if your projectile does not hit the skull bone perpendicuar, but at a shallow angle, where it easily can be deflected and simple glance off leaving only a flesh wound.



🔶If you are attempting heart/lung shots, and the projectile hits a shoulder bone first — will it continue on to reach and puncture heart/lungs?





🔶Great question, Enrique. No simple answers, but maybe you can tell us more details about your shooting scenarios. 👍🏼

Matthias






 
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55 foot pounds is a bit slow for 30 cal but if we are talking about more damage the larger Caliber is going to do more damage. Pellets do wierd things tho. So if you are shooting a 30 cal at 55 fpe you are going to have plenty of penetration as with any of those calibers for raccoons or whatnot. But here's the crazy thing, the damage actually increases with lower power. A 22 zinging at high speed may pass right through and so then the only damage is like a puncture as big as the 22 mushrooms but now let's say we shoot a 30 cal at 15fpe. Very slow! Well I guarantee you that if you headshots a raccoon with a big heavy 30 cal going that slow it would probably bounce off its skull but death will be instant. Bones would crush and all that energy would go directly to its brain. All that to say the one that does the most damage is subjective at 55 fpe I'd say the 30 would most certainly do more damage. The 25 would do fine tho. Dead is dead and a 25 through the head kills just as fast as a 30. For that matter a 177 or 22 to the brain is just as good as a 50 Caliber. If we are talking heart lung shots then bigger is better. If it was me I'd go with a 25 just for flatter shooting accuracy and still good penetration. Check out the edgunleshiy YouTube channel. That guy shoots 30 cal and 25 cal super slow and kills squirrel and raccoons and skunks instantly. It's a educational experience. I started doing the same thing and my kills are way more ethical now. 
 
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With the stated set of assumptions, the most effective one will be the largest one that has enough penetration to make it through vital organs. Meaning it does maximal damage to vital organs.

That can be a projectile that starts out big or starts out somewhat smaller and expands on impact.

However as a practical matter, it is often advantageous to have more velocity / penetration on tap for shooting at varied distances and the inevitable variations in what shot is presented. A broadside shot through the vitals may need to penetrate only soft tissue whereas a quartering shot may need to punch through a shoulder bone and twice as much tissue.
 
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Taking into consideration all what JungleShooter mention in the related links, there´s an imperative coclusion:

"Hunting killing power should not be messured in foot pounds because hunting power of a pellet is related with inercy off the pellet and with the size of the injured caused".

Then my seggestion is to create a new unit (Hunting Energy Unit) that takes into consideration the main factors for hunting killing power: inercy and diameter of the injury.

The formula that I proposse is:

Mass (in grains) times speed (fps) times diameter of the pellet (Cal).

If we apply this fromula for my initial question, then we can see that al 55 foot pounds the three Calibers would have very differet hunting killing power:









Sounds logic to me.



What´s your oppinion?


 
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Cool idea to come up with a formula, Emu! 👍🏼



I take it that we are talking Hunting Energy Units HEU at the muzzle — correct?

So, we'd probably need at least another factor in a formula — or maybe we'd need to calculate HEU at the target.



I understand that "Caliber" in the HEU formula is the diameter of the projectile as it passes through the quarry — so for example a hollow point pellet .22 would get a higher factor here than simply 0.2187".



Happy shooting all around! — Got my mourning dove already, well, it was a morning pigeon, actually, because it died before 8:00am. And I'm not mourning, I'm pretty pleased with myself! 😄

Matthias
 
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The formula would be:

HEU= PW * S * PD

where:

HEU = Hunting Energy Units

PW = Projectile weight

S= Speed

PD= Projectile diameter.

As JungleShooter says the HEU will change at the distance but that will only vary beacuse of speed decrease along travel.

If you apply this formula will notice that the arrow in bowhunting has a lot more HEU becuse of the weigh of the arrow and the diameter of the injury.

This meassure is much more useful, significative and precise that the foot pounds, at least for hunting purposes, .
 
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My approach would be the largest caliber with flattest trajectory within the range you are shooting. Obviously faster it is the flatter the trajectory but after certain point the gain is minimal, also the zero distance makes a big difference at closer distances because of the scope height.


here is what I found and you can validate with whatever ballistic software of just shooting:

- 650-750 FPS is very flat under 30 yards and need descent amount of hold over at 50 and lots of hold over after that 

- 750-850 is very flat or minimal hold over needed between 20-50 yards

- 900fps or more is very flat 30-70 yards with pellet and out to 80-90 yards with slug with minimal hold over or drop. 



If I were to hunt mainly hunt under 50 yards I usually tune my gun to shoot right around 800-820fps and zero at 20 yards, with that anything between 20 and 50 yards is less than half of a mil difference and I basically put the cross hair dead center. if I zero at 30 yards then is I would aim slightly higher than dead center because there isn’t a near and far zero which is also very easy. This makes quick shot super easy and I really don’t have to think about drop. 


also try to zero at the start or middle of your target range would make any speed much easier but not everyone has the range to change the zero out that far. Of course larger projectiles are more lethal but more accurate shots are even more lethal, just need to find a combo that works well for you. Although I am not sure what you mean by medium game but personally I wouldn’t use pellet smaller than .25 and slugs smaller than 22 if you plan on vital shots at all.



Then! If you don’t have to worry about collateral damage then smaller slugs wins hands down and pellet is the only choice if you have to worry about accidents. 
 
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I am not propossing to shot .30 Cal at 745 fps. I started there just for making a comparison among calibers.

My point is that we NEED to be able to meassure more acurately the killing power of our air rifles for hunting purposes.

And foot pounds are not the adequate meassure.

Taking into consideration what JungleShooter broadly explained, HEU, as above described, seem to be much more real for meassuring the hunting killing power.


 
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How can we determine killing power since it have as much to do with projectile size, weight, shape, material hardness, tissue/fur or what it might touch first as well as speed of the impact etc as well as FPE its carrying. There is simply too many factors to give certain formula for it. If we go even deeper my 224cal airgun is shooting 0,67" long 51gr spitzers at 1000fps yes it might hit soft tissue no bones etc and simply zip through without dumping much energy but now lets assume it hits bone and its 0,67" long and now magic happens it starts to spin and cause horrible wounds while dumping alot of energy. Well how this applys in real life.. That 110fpe+ spitzer at 1000fps might be really damn bad bullet for bird but it might keyhole inside raccoon after hitting bone and prove to be super leathal. No matter how much fpe ur gun is carrying as long as its dumping all that energy on right spot. In country where I live airgun hunting is not allowed and even if it would be we have energy requirments for game and class 1 animals require 100j+ so you are not allowed to shoot even a dove with any less.. Rabbits for example fall in category 2 and require 300joules or more so airguns wouldnt even be considered. 
 
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When we shot low speed, high caliber we will find out how much a small wind can drift our projectile. It's not important we shot 0.177 cal or tank missile when it going to miss.

A 0.22, 30FPE polymag will expand up to 10.5mm, almost double up. But much less BC which mean no more expansion over 50 meter.

If he want to hunt small type of animal why he should add extra weight? .25 cal will expanses almost double, way more 30 cal.
 
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