Same FPE Different Caliber?

[brawler1588]

So I have been thinking and wondering how 2 different calibers stack up against each other but setup to achieve the same FPE. So let's say a .22 at 20FPE VS a .25 at 20FPE would the 25 smack harder because of the slightly larger size or is the .22 going to be smacked harder because it may he going faster technically. Wondering if anyone has tried this it doesn't have to be this FPE specifically but thinking about running a low power .25 for some backyard stuff and was curious how it would differ from a similar setup just in .22. Thank you all

 

[Basher]

Are you achieving the same FPE by using the same projectile weight and velocity, just in different calibers? Are you referring to FPE at the target, or the muzzle? These are important factors. The FPE may be the same, but we need to know how you achieved the same FPE. The variables at play can have a DRASTIC effect on external and terminal ballistics.

 

[L.Leon]

Since 20 FPE will suit on critters on your “backyard stuff” requirement. I would go with .22 given your proposal, it’s less expensive and as effective sub 50 yards and should express a flatter trajectory… Whichever way you go its sure to be fun…

 

[brawler1588]

Are you achieving the same FPE by using the same projectile weight and velocity, just in different calibers? Are you referring to FPE at the target, or the muzzle? These are important factors. The FPE may be the same, but we need to know how you achieved the same FPE. The variables at play can have a DRASTIC effect on external and terminal ballistics.

Look at it multiple ways, let's say muzzle velocity, and how much of a difference will weight and speed have if end FPE is 20FPE

 

[brawler1588]

Since 20 FPE will suit on critters on your “backyard stuff” requirement. I would go with .22 given your proposal, it’s less expensive and as effective sub 50 yards and should express a flatter trajectory… Whichever way you go its sure to be fun…

You know me I'm using .177 on most my backyard critters and have different calibers for different tasks just thinking out loud about how caliber size effects it even if it's the same end FPE

 

[Bander124]

I’ve shot the h&n 21g in .22 the same energy as the h&n ftt .25 21g found the larger caliber smacks harder but the smaller caliber drills deeper. I just assumed it had more to do with surface area.

 

[Ranchibi]

For short range shots I don't think it would make much difference but the .22 will shoot a flatter trajectory and should have better penetration, the .25 would still hit hard with a larger surface area. My choice would be .22 for a flatter trajectory.

 

[OutdoorEDventure]

Coming from the center firearm world Ft.lbf has never made sense. For example a 80gr bullet traveling 3765 FPS -vs- a 140gr bullet traveling 2700 FPS. At 100 yards the 80gr bullet is running 3450 FPS with 2110 ft.lbf versus the 140gr bullet 2550 and 2070 ft.lbf.

In this example the 80gr bullet is running 750 FPS faster at 100 yards than the 140gr bullet at 0 yards but delivering 440ft.lbf less at the same 100 yards.

Real world field experience has prover both bullets have dropped Nilgal (average 500-660 lbs) at 100 yards. How do you measure ft.lbf in this scenario? How quickly the animal drops? How quickly they expire?

For pellet hunting I'd stick with the most accurate projectile you can stick between the eyes of a critter at reasonable distance to the size ratio of the species hunting.

 

[Reg Creep]

Enter the stats into stelok or some other FPE calc and compare.

For giggles, I'll guess that the .25 has the advantage beyond range X, and that inside of range X .22 sees little if any advantage in FPE.
I would also guess that .25 would be significantly more efficient than .22 at the same muzzle velocity.

I don't have a good guess as to penetration and expansion. That would likely depend on the target.

 

[MongooseV8]

I think if the difference in fps is high enough, the lighter pellet is better for me. While hunting I like the 15.9 Hades/Atomics and push them really fast so they get some deformation. A 25Cal pellet at the same fpe will not deform much, if any at all. Sometimes that is good, like for a skunk sized pest when you want some pen. But mostly I am after rat sized pests and want as much immediate expansion as possible. And since pellets really need a lot of speed to do that I choose the lighter options most of the time. The trade off is the lighter stuff doesnt have as good of a bc and wont do well further out compared to something heavier.


There are other factors as well, such as the 25Cal Hades are a different design. They dont seem to deform nearly as much at any speed I have tested. But for other uses like paper punching I dont know if there is an advantage either way.

 

[Corvid_hunter]

I used a .25cal tuned to 650fps with 25gr JSB pellets to drop a fox with a head shot at 40 yards. Worked just fine. I think heavier pellets hold more energy over longer distances than light pellets if I'm not mistaken.

 

[dgeesaman]

There have been many efforts over the years to try and answer this question. In countries with fixed FPE limits this really matters. I’m not in a position to summarize them but they are out there awaiting your research.

I think what matters more is knowing what kind of impact is most deadly. Do you need penetration or will shock kill? Some critters have thick skulls and tough hides so that penetration is essential. Others will get pass through if there is too much penetration so the larger caliber will tend to dump more energy into the target.

Pellet choice has much to do with penetration though. So if I chose the 25 I can usually opt for a Polymag when more penetration is required.

 

[SilentSquirrel]

It seems to me you could get an answer by plugging the variable into a ballistic program
ChairGunPro, for example, is able to give results that show FPE at the target, as well as the projectile drop curve.
And you an see both overlayed on a graph

just my 2 fpe
Edward

 

[dens228]

The heavier projectile will retain more of the muzzle fpe down range.
Personally I'd go heavier at the same FPE.
Think of being hit with a wiffle ball bat vs a baseball bat.

 

[JimD]

I used to use H&N FTTs in my P35-25 because they were the most accurate pellet at the original plenum size. They weigh 20 grains. My P35-22 likes H&N Baracuda Match which weigh 21 grains. The 22 only pushes them about 820 fps and I adjusted the regulator of the 25 to push the 20 grain a little faster and they were both at about 32 fpe. I killed 18 squirrels with my 35-25 at that tune. I've taken 10 so far with the P35-22 (I've had it almost a year less time). They are both very effective. In both squirrels and in tests in wet paper the 22 penetrated a bit further but the 25 sent all the way through 15 of the 18 squirrels I took with it. I have not lost a squirrel with either gun. Even with shots not ideally placed. I remember one squirrel with the 25 that was hit about at the joint of the jaw. Missed the brain entirely. Dropped immediately anyway. The skull was crushed. I've since installed a larger plenum on the 25 and retuned it to almost 50 fpe with JSB MKII 34 grain. I haven't shot a squirrel with it but I am sure it is overkill at this power level.

My Prod and my P35-177 are also at about the same fpe, 18-19 fpe for both. The Prod pellets are H&N FTT copper plated at 14.66 grain and the P35 is shooting H&N Baracuda Match 10.6 grain at nearly 900 fps. Squirrels drop a step or two slower with these guns but they perform about the same. But the Prod velocity is in the low 700s so the trajectory is not nearly as flat. But the 177 pellets have a lower bc so they are more sensitive to wind. I think they are both better at shorter range both from a power and other factors. 30 to 35 yards is about as far as I want to use them.

I think 20 fpe is awfully low for a 25. For very short range or very well known distance I guess it could work. The FTT is about the lightest 25 caliber pellet and could only go about 675 fps. If your gun was accurate with them I guess it could work but if it likes heavier pellets you'd have to go slower. I would want to keep the fpe up to 25-30 fpe minimum.