Question About .177 vs. .22 For Jacks & Cotton's

[pecci]

I'm contemplating a Benjamin Fortitude.  A video from Airgun Depot did some ballistic testing.  Some info from it.  (Btw, I want to use it for hunting rabbits & jacks in the desert.  The jacks especially, if jumped, run and when they stop & in sight, they are 50+ away.  If we do a sit & wait, we see them much closer).

Here is the info. followed by my question:

After 75 shot strings, the .177 velocities are remarkably consistent.
 
.177 (10.5 gr. Crosman Prem. Ultra-Mag) - Ave. Velocity: 845 fps ... Ave. FPE: 16.65 ft.lbs. Standard Dev: 8.85

.22 (Gr. not mentioned but I calculated a 13.2 gr. & pellet used) - Ave. Velocity: 790 fps ... Ave. FPE: 18.60 ft.lbs. Standard Dev: 16.16 

.177 was quite consistent, while the .22 was noticeably less.  The presenter stated that the .177s were more typical (they looked higher than most, to me). --- The .22 was said to be lower than typical (I agree).  *Since his target test (of 5 dif. pellets) did not use a 13.2 gr. perhaps the .22 #s are in error.

My question is (if #s are all correct), although the .177 smaller in diameter the ft.lbs. are only less by 2 1/2 ft.lbs. than the .22.  Would that mean the .177 having a flatter trajectory, although smaller in diameter, would be as effective as a small game/varmint round?

[Rico14]

I shot jack rabbits with .177 for years. They're pretty fragile and it doesn't take much to bring them down.

[JimD]

If the flatter trajectory helps you put the pellet into the right spot on the jack rabbet, then the 177 might be the right choice.  You may not have time to use a range finder and determine the drop on the 22.  But ft lbs is only one measure of lethality and perhaps not a great one.  Air rifles work at velocities similar to hand guns so I sometimes look at research on stopping power for pistols for useful information.  One of the good observations is that only a central nervous system hit is reliable for stopping.  The other way to stop the target is to cause enough blood flow loss that the brain doesn't get oxygen.  For that you need sufficient penetration and a large enough permanent cavity (they say temporary cavity doesn't count because velocity is low and within the elastic limits of the flesh (it just moves back)).  Permanent cavity is the projectile diameter absent expansion (which is normally true for pellets and if you get expansion you reduce penetration).

Long way of saying the bigger hole of a 22 is desirable but not as desirable as putting the projectile in the right place.  Even a fairly high velocity 177 has significant drop at 50 yards, however.  So maybe you need to know your yardage either way. 

[ranchibi]

I have all .22 cal PCP’s....don’t underestimate .177 cals! Guy recently posted a photo of a 225lb boar shot with a heavily modded Hatsan Flashpup in .177 shooting 18gr slugs @ 1050fps...shot placement key like said above 👍.

[JimD]

I would test penetration to be sure but a pellet like a polymag or metalmag might also let you make a roughly 22 sized hole while still giving you the 177 velocity.  But I would want to be sure it has sufficient penetration in wet newsprint.  I consider something like 3.5 inches to be sufficient.  I know the pellets out of my Prod that penetrated that far killed the squirrels I hit with them.  But they did not shoot through a dead one I tried them on at 20 yards.  They went through and stopped in the skin on the far side (head was out, skirt was inside).  At 50 yards, they would probably be marginal (and I would be seriously challenged to put them in the right place).  I consider my Prod to be a decent 30 yard gun.  Might be able to do 35 or maybe even 40 with a good rangefinder and ballistic data but I cannot imagine 50.  I'm only shooting 14.66 grain pellets 700-750 fps.  To reliably do 50 yards I would want muzzle velocity closer to 900 fps. 

[ray1377]

Have killed way more bunnies with a .177 than I ever did with a .22
My favorite bunny gun is a 2240 converted to a bottle gun regulated to 900 psi and a 22 inch barrel.
With 7.9 grain CPHP's it will put 10 inside a dime at 40 yards going 780 fps, so just a little over 10.6 ft/lbs of energy at the muzzle.
And most will tell you that at lower power settings the gun will shoot quite a bit quieter than one that's tuned hot.
Especially if you have an LDC on it.
I always go for head shots and they drop in their tracks.
So it really boils down to shot placement as much or maybe more than total ft/lbs of energy. You can have a 50+ ft/lb gun but if you can't hit with it what good is it?
Think about the folks in the UK who are limited to 12 ft/lbs or less. They have learned to do a lot with less.
Sorta makes those wally world break barrels they claim shoot 1400 fps sound kinda like a waste don't it?

Ray

[Blowpipe Sam]

Hares and rabbits just ain’t as tough as squirrels.  The last time I shot Jacks was 20 years ago but I remember thinking then that we were killing them with body shots that never would have anchored a squirrel.  Cotton tails I have shot recently and they are just plain delicate.  Boiler room shots with a .177 are perfectly adequate on cotton tails IMO.

[Motorhead]

I've often thought you could swift kick a cottontail in the ears and kill it ... Super fragile bunnies.  Jacks on the other hand not so much requiring a brain shot or boiler room violation to anchor em.

Sadly i've had far too many jacks run from sloppy shot placement threw the years .... while they will die, just not where they give you access to retrieve them 

Shot within realistic range for the caliber .... CALIBER does not matter .... Shot Placement does !!!

[Bladebum]

I have killed more living things in my life than I care to mention with everything from a red Ryder to a 338 ultra mag.

There are pros and cons of caliber choice/power. But NOTHING beats perfect shot placement. Not a thing.

Physics are physics, the heavier, faster moving projectile with higher relative bc's will buck wind better and carry more energy downrange. Those things are only important if you need them.

That was a long way of saying that a 177 fortitude will kill exactly the same as a 22, 25 , 30 or anything else if you put that pellet in the head or through the heart.

[pecci]

Lots of great comments, coming from legit sources, because of actual experience.  Thanks to all!