GTA
All Springer/NP/PCP Air Gun Discussion General => European/Asian Air Gun Gates => German AirGun Gate => Topic started by: Tramo on June 27, 2011, 11:59:02 PM
-
Shot by the same spring/cylinder/piston, the same length barrel, and the same stock.
Will one, a .22 pellet or a .177 pellet hit the target with different impact ( knock down power ) as we like to call it.
Same exact energy spent to propel the pellet = same impact energy.
What's the truth ?
What's YOUR theory ?
.22 out of a RWS 48 won't even penetrate a ground hogs' thick skin at 50 yards.
.177 goes in, won't knock him down but he'll bleed to death in his den - internal if not external.
I would love to hear from all who regularly shoot both calibers.
Bring on the discussion/debate.
-
My 22 350 shooting 14.6 gr pellets puts ojt more fpe at 28 yds than my 177 350 or 470 do point blank.
-
First of all, you have to examine the idea that the same energy spent will produce the same results.... Unfortunately, it won't.... First let's look at what happens inside the gun.... be it Springer, CO2, or whatever....
The .177 cal has an bore area of 0.0246 sq.in.... The .22 cal (actually 0.217") has a bore area of 0.370 sq.in.... 50% larger.... Since the force available to accelerate the pellet is proportional to the area, there is 50% more force available to accelerate the larger pellet.... Two identically proportioned pellets would vary in weight by the cube of the caliber.... ie if a 7.8 gr. pellet in .177 is scaled up to .22 cal (0.217") it would weigh 84% more which is 14.4 gr... Now we have an 84% heavier pellet being accelerated by a 50% greater force.... That should result in a velocity (in the same barrel length) for the larger pellet of 1.50 / 1.84 = 0.815 times the velocity of the smaller pellet.... If we take a typical springer like a Diana 34 which shoots a 7.8 gr. pellet at 850 fps, we would expect the .22 cal version of the same gun to shoot a 14.4 gr. pellet at 693 fps.... Don't you love it when theory and practice agree?....
It is this mathematical relationship that gives a .22 cal gun the ability to deliver more energy than a .177 cal gun with the same power plant.... Using the example of the Diana 34, in .177 cal the energy is 12.5 FPE.... whereas in .22 cal the energy is 15.4 FPE.... If you have been wondering why the .22 cal version of a given gun always seems to have the edge over the .177 version.... now you know why....
Now let's shift to what happens to the pellet after it leaves the barrel.... This has everything to do with the Ballistics Coefficient and you may have heard that typically .22 cal are better for "bucking the wind".... Is there anything to that claim?.... Let's go back again to the two pellets used in the example above.... The Ballistics Coefficient is the Sectional Density divided by a "Form Factor".... We used two pellets of identical shapes, so the form factors are the same.... The Sectional Density is a measure of how heavy the pellet is for a given caliber.... It is the pellet weight in lbs. divided by the bore squared.... For the 7.8 gr. .177 pellet the SD is (7.8 / (7000x0.177x0.177) = 0.0356.... while for the 14.4 gr. .22 cal pellet the SD is ( 14.4 / (7000x0.217x0.217) = 0.0437.... which is again, 23% more.... The .22 cal pellet should, in theory, have a BC which is 23% better than the identical shape would have in .177 cal.... Another advantage to the larger pellet.... Not only does it leave the muzzle with more energy.... it retains that energy better downrange as well....
Have you ever heard the term "Momentum" used referring to the "Hitting Power" or "Knockdown Power" of a bullet/pellet?.... Whereas the energy (FPE) is proportional to the square of the velocity.... the momentum is simply the velocity times mass.... If you have two pellets with identical energy, the heavier one will have more momentum.... Let's exaggerate to make it easier to understand.... by comparing two pellets of identical energy, but one is 4 times heavier than the other.... The heavier one will be travelling half the speed since the energies are equal.... but it will have twice the momentum....
10 gr. pellet at 1000 fps = 22.2 FPE.... The momentum is (10x1000) / (7000X32) = 0.0446 lbf-s
40 gr. pellet at 500 fps = 22.2 FPE (same).... However the momentum is (40x500) / (7000x32) = 0.0892 lbf-s (twice as much)
Using our pellets from the example above.... the 7.8 gr. pellet at 850 fps is 12.5 FPE and the momentum is 0.0296 lbf-s.... while the 14.4 gr. pellet at 693 fps is 15.4 FPE and the momentum is 0.0446 lbf-s.... which is 50% greater.... That means that the .22 cal pellet, fired from the same gun, will "hit" 50% harder than the .177 pellet.... If you were firing at a pendulum which "absorbed" the impact, the larger caliber would swing the pendulum 50% further....
Since this thread doesn't address trajectory but only "impact".... I think you can see which camp I'm in.... ;D
Bob
-
What Bob said. There, lets see ya debate that. LOL.
Richard
-
A nice scholarly explanation, Bob.
I also wanted to let the OP know that wounding an animal, allowing it to escape into its den, to die a slow, painful death later, is not the kind of "hunting" that an ethical person would intentionally do.
That kind of thing is bound to happen occasionally, because of muffed shots or a particularly tough g-hog, but it's not the sort of thing to feel good about.
My suggestion would be to bring your shooting distance within 35 yards, but I can tell you that the RWS 48 can do the job on a g-hog at 50 yards, just as long as you a) use a suitable pellet, and b) restrict your shots to the "fusebox," brain shot by striking between the eye and the ear.
By proper pellet, I'm talking about either a domed or pointed pellet of suitable weight, preferably 15 grains and up.
Some good choices would be the JSB Exact Jumbo 15.8 grain, JSB Heavy, H&N Baracuda (aka Beeman Kodiak), and the mighty Predator Polymag.
-
very informative "rsterne"
-
Thank you professor!
To break it down barney style. Bigger bullet going barely slower makes more wizz bang giving you more pop on target! ;D
-
PERFECT !!! Great explanation 'rstern' for "lab" measurement in a "vacuum". Taking into account the slowing forces of "gravity" and "wind resistance" both also being 1.5 times on the larger pellet - are the results the same ???
In my experience, after owning both an RWS 48 in .22 and .177, I know which one (seemed) to have more energy at impact - maybe not right in front of you, but at a distance. One cannot always get right up next to a varmint like he can a target, and accuracy counts too.
One thing for sure - I love to learn from people who can back what they say with science....
Just so you know - I shoot the varmints with a powder 17 HMR, and they don't take three steps let alone go suffer. :)
Thank you for the replies - keep 'em coming
-
rs good teaching, Tramo I have no problems taking G-Hogs at ranges of 85yds with my spring guns and the 48 in 22cal should have enough power to do the same but I only take head shots! body shots will take them down but as you have found out they'll run back to their den :- so I never make those kinds of shots, because its either a clean kill or a miss! and the power of the 48 assuming yours is up to snuff around the 800fps range with a 14.3gr pellet you should get a clean pass thru with a head shot out to 75yds easily :P
-
Bob, that was a GREAT post! Thank you!
-
Excellent explaination!
Saved for posterities sake.
-
Look up Perfesser Taylor's Knock Out formula aka "TKO". He developed it at the University of Serengeti. I've applied it to air guns and it seems to hold up.
Don't discount pellet hardness, either. There have been reports, here and elsewhere, of seemingly sure, point-blank shots failing miserably because the ammo was a dead-soft wadcutter. Negligible penetration and insufficient transferred shock. And the game is important, too. A bird at fifty yards likely won't know the difference between a .177 or .22 since both might be pass-through shots. In these cases, it's mostly wound channel in a relatively small body. Either size hole works.
-
Gravity doesn't really come into any of the energy formulas. the only role gravity has is in the trajectory. wind resistance or drag is an issue, but that is taken care of, if I understand all this correctly, with the ballistic coefficient.
as far as wind drift is concerned, in objects of identical shape and differing mass, the heavier object will require a larger amount of energy applied (stronger wind) to change its course due to its larger inertia.
-
Well, the .22 will transfer much more energy and more SHOCK value to its target, and in a game where the transfer of energy, to effectively disable the target, 22's and larger are king. Im in favor of the .22 due to its energy retaining properties, superior ballistic coefficients, availability of ammo (over the .25) and marginal differences in velocity putting it as the best small game candidate between the .177 and the .25cal,.... heck, i shoot the 18.1gr JSB jumbo heavies with my npxl, and i always see a complete pass through under 50 yards. Besides, at 25yds, i can shoot 4 or 5 of those pellets through the same hole. My vote is always for a 22 or bigger, because airguns dont usually kill by blunt force trauma and or hydrostatic shock value like high powered rifles, airguns kill by producing a wound channel or a wound cavity to destroy vital tissues, essential for the life of the critter. 22's have the potential to carve out more tissue and destroy more area if they fragment (hollow points/poly-mags)
-
Agreed! :P
-
"Gravity" affects only the trajectory.... The variables there are Velocity and Ballistics Coefficient (and angle if you are shooting uphill/downhill).... If you were shooting in a vacuum, then only the velocity would matter.... Since we're not, the BC is important because the pellet slows due to wind resistance....
"Wind Resistance" is determined by the BC.... A .22 cal pellet of identical shape to a .177 pellet will have a BETTER BC because although it is 50% bigger in cross section, it weighs 84% more.... The Sectional Density is higher, the shape (form factor) is the same so the BC is higher.... At the same velocity the larger pellet will have less drop, and less velocity and energy loss....
"Wind Drift" is probably the least understood and most argued part of external ballistics.... The amount of wind drift (ie the amount the pellet drifts sideways due to a crosswind).... is determined ONLY by the DIFFERENCE in the flight time to the target under actual conditions compared to what would have occurred in a vacuum.... The variables are the wind speed and direction, distance to the target, Velocity, and Ballistics Coefficient.... Since for any valid comparison, the wind speed and direction and the distance to target are the same.... we are left with Velocity and BC.... For two pellets of identical BC, the one starting out faster will drift less because the time difference is less.... For two pellets starting at identical velocity, the one with the better BC will drift less.... again because the time difference is less.... Of these two factors, the BC is by FAR the most important....
Let's look at our previous example, using Chairgun to do the wind drift calculations for us.... Let's assign a BC of 0.020 to the .177 pellet.... Using our previous calculations, the .22 cal pellet should have a BC 23% better.... which is 0.020x1.23 = 0.0246.... Let's use a 10 mph crosswind and the target at 50 yards.... Here are the results....
.177 cal; 7.8 gr; 850 fps; BC 0.020 - At 50 yards, V = 621 fps, E = 6.69 FPE, Drift = 5.41"
.22 cal; 14.4 gr; 693 fps; BC= 0.0246 - At 50 yards, V = 537 fps, E = 9.23 FPE, Drift = 5.29"
Note that even though the .22 cal pellet started out at only 693 fps instead of 850 fps.... that it actually had LESS wind drift at 50 yards.... Also note that while the larger pellet only had a 23% advantage in energy at the muzzle.... at 50 yards that advantage has grown to 38% (9.23/6.69 = 1.38)....
Interesting discussion for sure.... The same math can be applied to the advantages of a .25 cal over a .22 cal of course.... and so on.... Aren't we fortunate that we live in a era where .25 cal guns (which were once really a novelty).... now have the power to have a flat trajectory and awesome hitting power.... They currently reign supreme for hunting at 100+ yards....
Bob
-
Professor rsterne, what do you guys think??? lol!!! Thanks for the lesson David
-
Rsterne that is alot of math! R u a nuklear sientist! Lol seriously tough good lessons.
Tramo. Ive chronied my guns out to 28 yds. The heavier pellets started out slower but retained more velocity at longer ranges. I actually switched to 10.2 gr jsb's in my 177 cal 350 because at pb they were about .3 fpe behind the 8.4 gr but at 28 yds they lost less than half the velocity of the lighter ones. That gave them more fpe down range. My 22 cal 350 also put out more fpe at 28 yds than both of my 177 mag springers at point blank.
-
OK, this is awesome. Bob is REALLY smart and a really good writer/teacher - and I bet it's all from the top of his head, not google.
BUT, I'm REALLY stupid on this subject... and have a need to understand.
We are assuming that the two guns are EXACTLY the same, with exception of the bore, one being .22 and the other .177
If the spring/piston releases exactly the same amount of energy to propel the
two different size pellets, AND the two pellets hit the target with two very different energies.....
WHERE did the extra energy from the smaller pellet go ???
I remember something about E=MC squared - where E= energy, M=mass, and C= speed of light or something.... but the "extra" energy can't just dis sapear.
-
The internal lossses in the gun are likely mostly lost as friction and heat.... The larger caliber is simply more efficient in the way it uses the amount of air compressed.... or in the case of a PCP or CO2 the amount of HPA/CO2 stored in the valve.... More of that energy is changed to kinetic energy instead of being wasted.... Basically none of the potential energy in the gun is lost.... it all changes form.... It's just that in the larger caliber more of it gets converted into kinetic energy of the pellet....
Externally, the larger pellet (of the same shape) retains it's energy better.... ie it loses less to air friction.... The frictional losses would go into kinetic energy or heat (even sound) in the air it passes through....
Bob
-
Two minor points. A) If you are shooting anything and consistently making pass-through shots, you are not shedding all of the pellet's kinetic energy. Basically, it comes down to a slightly larger wound channel, since I don't think springers create substantial hydrostatic shock like a firearm.
B) In a gun, say a Diana 34 or R9, where the only difference is in caliber (.177 barrel or .22 barrel), one will not necessarily be superior in net performance than the other. The .22 doesn't use the power plant any more efficiently than the .177. Most guns use the same transfer port size, it being cheaper to build them this way and, I suspect, the configuration is a compromise between the two calibers, if even that. The smaller bore creates a certain amount of back pressure so that the piston stops at the optimal point in the stroke. The larger bore, offering less resistance, makes up for it in pellet weight. Inertia or the force required to start the pellet moving (one nanosecond after the piston's "Big Bang", if you will) remains about the same.
There are some guns that seem to favor one caliber over the other. The Diana 54, for example, is generally recongnized to be a bit more efficient in .22, along with the 48/52, basically the same power plants. But, again, you can shoot heavier .177 pellets in these nearly as well. Best bet is to test the gun/pellet combination, meaning .177/.22, to see which seems to work best. Of course, that's kind of expensive, buying both guns.
-
Good point.... and an excellent example is that most .25 cal springers are actually less FPE than their .22 cal cousins on the same frame.... There are a few exceptions, but most of the "medium" springers have a bit more power in .22 cal, and the "magnum" springers significantly more FPE in .22, than in .177.... The sizing of the transfer port has a lot to do with the optimum caliber for a given swept volume.... Guns with really small swept volume can actually produce more energy in .177 than in .22 cal... they just don't have enough volume for the larger caliber....
Still, the math is valid for most guns.... The .22 CAN get more power from the charge of air just based on the physics.... Whether you consider that is truely a matter of "efficiency" or not is a matter of symantics.... What I should have said, I guess, is that in most guns the greater bore area of the larger caliber CAN allow it to develop more energy.... PROVIDING there isn't something else (like a transfer port) skewing the results.... The same would apply to PCPs or CO2.... Stick in a small enough transfer port or a really small valve, and you could probably make a .177 outperform a .22....
Bob
-
Ahhhh, finally, the word "CAN" - a HUGE difference in the explanation.
Between the two of you "rstern" and "redfeather", you should write a book on this subject.
The deal is - I at one point did own both guns. Both Diana 48's ( originals, mid to late 80's - when Diana still made their own guns).
Over 50 yards the .22 couldn't hit the side of a barn if it was painted florescent orange. Making a "hit" shot from close to far distance was impossible withour re-sighting the gun to that distance. ( I'm REALLY good with bullet drop with a powder gun). AND, if I hit something (animal), most times he would turn around and look at me like I should try a real gun next time.... LOL
When I got the .177, I was finally a marksman.... I could take out a bird through his eye, without a mark on his face. I could take a fly off a flower without touching the flower, AND I could put 5 shots through the same hole at 30 yards all day long.
AND to make things even rosier..... with a tiny shot of oil in the piston chamber, the thing would sound and preform just like a Powder .22 - and even smoke after a shot. ( Yes I know the diesel effect ).
Needless to say, I took a great loss and practically gave the .22 away. Perhaps I just had a "gimp" gun ????
-
If your referring to the 48 in .22cal your right because their usually hammers in that caliber and our perform the .177cal in that gun for hunting fur critters JMHO! :P
-
I would have thought the idea that guns CAN have something wrong with them.... or that they CAN be restricted in some way either intentionally or because they were improperly assembled or had something wrong with them.... would have been pretty obvious.... It's pretty much like saying a big block CAN develop more horsepower than a small block.... but not if you choose to put a single barrel carb on the big block....
If you are comparing a .22 that is not dieseling to a .177 that IS dieseling.... then no wonder you thought that the .177 had more power.... hardly a fair comparison.... The horrible inconsistency you suffered with the .22 cal D-48 would lead me to belive that there was a problem with the gun.... It could have been something as simple as a bad breech seal or a score in the cyclinder wall.... It could also have been a piece of swarf floating around and partially blocking the transfer port.... possibly even in an inconsistant manner....
I would agree with your assessment that you had a "gimp" gun.... Don't base your view of .177 vs .22 on that single experience....
Bob
-
Yes, I guess it could have been a burr in the barrel, the choices of pellets way back then, or a number of other things....( bought the .22 used) but when I got the .177 (BRAND NEW) and found out what it could do, I didn't really care for the .22 any more.
And yes I dieseled them both, or tired - the .22 didn't have enough compression (back pressure) to "ignite" the oil...
Anyhow I appreciate all your time in hepling me understand what happened and forming such a long lived bias ( in my mind ) on the subject.
-
What Bob said. There, lets see ya debate that. LOL.
Richard
are you kidding me? I forgot what the question was but he answered my question..being in my line of work I agree the bigger they are the harder they hit! That's a fact!!!! Thanks Bob
-
Now THAT explains where I'm coming from and why I'm biased towards the .177.
-
While I agree with many of the points about trajectory.... the OP specifically asked about the IMPACT of the two calibers from the IDENTICAL powerplant, which is what I addressed.... Had he asked about the trajectory of the two calibers, or why a medium springer is easier to hit with than a magnum springer, or what caliber is better at 100 yards, or a variety of other questions, I would have taken a totally different approach.... I tried to answer the question asked....
I've shot a magnum springer and I don't care for them.... They are much more difficult to hit with, at least for me.... If you need a flat trajectory and good performance in a cross-wind, then for me that means a gun that will shoot 850-950 fps shooting round-nose pellets.... My choices would be a medium powered springer in .177 (like a D-34 or HW-95 or their clones) for small game.... a .22 cal PCP running 30-35 FPE for most airgun hunting.... or a "Condor class" .25 cal PCP for 100+ yards or for larger animals....
I have done extensive testing of pellet Ballistics Coefficients at varying velocities and I can state with certainty that the BC is NOT fixed but varies with velocity.... and not in a linear fashion.... Depending on the weight of the pellet, the BC starts to take a nose-dive over 800-950 fps, with the lighter pellets starting to lose BC at the lower velocities.... If you want to shoot at long ranges, then you need a round-nosed, heavy pellet (for the caliber) and keep the velocity below transonic, which is Mach 0.8 (900 fps) for most of it's flight.... That will give you the best possible BC over the entire flight to target.... and therefore the best resistance to wind drift.... Larger calibers help as well because of the better BC for a similarly shaped pellet.... Velocities over 1000 fps REALLY hurt the BC on even medium weight pellets.... On a great performing pellet like the JSB 18 gr. Heavy, the BC is half as good at 1000 fps as it is at 800 fps (which is near where it peaks at about 0.040).... At 1100 fps (barely subsonic) it drops by half again to values more typical for a wadcutter at 600 fps (about 0.010)....
I know this is getting WAY off topic from the original question asked.... but I figured if the debate is going to be broadened to trajectories, hold sensitively, and what is the best caliber for different uses, why not?.... ;D
Bob
-
LOL, this is GREAT.
First off I should NOT have titled this a "debate" ( even though there are many views, and the math is really only 100% accurate in a "lab" type vacuum setting).
What's important is that I'm getting a ton of info, and I love learning....
Most of my shooting today is with powder guns, small rimfire to be exact, however I have found my preference to be the same with those. I will take the 17 HMR over the .22 Magnum anyday. ( for those who don't know, the 17 HMR is a necked down .22 Magnum casing with a 17 grain 17 gauge bullet, pretty much the same as comparing the .177 and .22 pellets and shot by the same amount of powder).
30 grain .22 at 2,200 FPS
17 grain .17 at 2,650 FPS
I'll take the 17 anyday, wheather it be for Target OR Varmint, close or far.
The question has not been fully answered in "real world" proof.
The "discussion" has expanded....
AND
ALL IS GOOD
Thank you to all !!
-
well anyway you want to go with this all I have to say is I regularly shoot distances with a springer R1's 48" 460" Webley Tomahawks'' I can go on but their all in .22cal out 100yds + and they knock the snot out of what ever I shoot and kill with proper shot placement! I've done the same Kinda shooting with my 20cal rifles and .177cal rifles R1' R9' you get the point, and unless its a soft target like rabbit size game or smaller these 2 calibers work well out to about 100yds with heavy pellets I don't trust them for anything bigger. The 22cal works on anything and over kill on allot of stuff but IMHO the 22cal is the best all around caliber for airguns! They don't shoot as flat as the other 2 cals but that's what mildots are for, but I guess if your shootin little stuff at short ranges you probably don't need a 22, :P
-
what works for some may not for others. I'm with you on the .177 wagon. i also like my cz in 17hmr as well. ;D
-
I just ordered a new Volquartsen 17HMR
12 weeks, made for me... :)
-
Back on toppic.
I do understand now that as far as a "spring-air" rifle goes - the .22 pellet is "capable" of capturing and transferring MORE of the Kinetic Energy produced by the Spring/piston action of the gun over the .177 pellet.
I DO understand that there are certain changes one could do to bring the "Power" or "Impact" of the .177 to VERY near that of the .22 .
I do understand that the flatter trajectory of the .177 is preferable for distance shots.
Perhaps I should have asked "which has more impact at long distance" ??
-
The 22cal! :P
-
A minor point, if I may. This is the German Gate, not the Air Gun Gate. This thread will get lots more play if it is in the area for general discussions.
Don't - repeat, do not - add a drop of oil to the pellet to promote dieseling. Especially in something like a 48. Yes, it will crack like a .22lr. It will also toast the seal and, in all probability, snap the end off of the spring. I say this not to admonish anyone but to enlighten any newcomers to this thread.
I'm not at all sure why a .25, in a springer, will necessarily create a greater wound channel than a .22. Wound channels are both wide and long. A lot of these .25 springers appear to be rather marginal unless the range is shortened. I guess they are based upon .22 power plants. In these, the wound channel will most likely be wider but shorter than the .22's. In the .22, you will be clipping more vitals as it goes deeper. That's disregarding pass-through shots. Of course, up close and personal, a .25 will do more damage. But there are guys with the odd 48 in .25, supposedly discontinued because of under-performance, who have reported some pretty strong results.
.22 springers generally do not have the effective "target shooting" range of the .177 since they have a bit more balloon trajectory. .177's tend to shed more velocity and, therefore, lack energy or "don't carry up" at extended ranges. The best thing to do, in my book, with either caliber, is to set up some kind of test media at various ranges to judge the effective killing range. This will also depend upon the game hunted and the hunter's skill level. A consistently great shot can stretch any gun out a bit more than an average shot. I think this is really a more salient point than which caliber is more effective, given anything. For example, I have seen posts wherein the author has made shots at one hundred plus yards with a .177 R9 that the same fellow would have poo-poo'd with an R7 at fifty. Caliber and power are only half the game.
One thing I'm not quite understanding and that is how BC is affected by speed. I am sure some designs need a minimal speed in order to stabilize. And it's hard to compare pellet performance in springers with that in PCP's which are a lot closer to powder burners in many respects. For one, they can employ bullet-shaped projectiles whereas the diabolo or shuttle cock appears to be best suited to springers or low powered, CO2 guns.
-
Thanks RedFeather for more important info.
I put this subject in the "German" gate for two reasons
1) Because the guns I was comparing were both Diana 48's.
2) I saw that many people owned both calibers in the 48.
Figured this was the place to get some "real world" FACTS. AND remember, in the initial question, I asked for info from those who REGULARLY SHOOT BOTH.
It's turned out OK, and I love the info coming in from all directions. Even the opinions from those who have never touched both guns.
2)
-
I must have missed that about the 48's. Personally, I would take a 48 in .22. I have a 54 in .177 that I like a lot but think it would be better suited to .22, as well. For one thing, you are a bit limited in pellet selection with the .177. The guns are powerful and should be shooting heavy pellets, so 7.9 grainers are a bit light in .177. I think the .22 shooting standard 14.3 grain would be less hard on the spring. Still, either one is fine. And, if you can snag a .20, do so, by all means. They are out there and snapped up before the internet ink is dry on the classifieds.
-
One thing I'm not quite understanding and that is how BC is affected by speed. I am sure some designs need a minimal speed in order to stabilize. And it's hard to compare pellet performance in springers with that in PCP's which are a lot closer to powder burners in many respects.
Drag. Ever go for a run/bike ride towards the beach? You might have noticed that it is considerably harder to run/pedal into the wind (simulating speed or velocity) I go for a bike ride every morning, about 32 miles to the beach and back, and fighting the wind not worthy. i can pedal at 5mph just fine, at 10mph, the wind is "noticable" at 14mph, the wind is constantly slowing me down, and anything above 17mph, my aerodynamics are much the same of a shaven brick cutting through the air. So my point is, there is a "sweet spot" for a mountain bikes speed, just like there is a sweet spot for a 1978 ford f-150 (about 50 to 55mph) and there is a sweet spot for a pellet with certain ballistic coefficients. I will bet you can't throw a book nearly as fast as you can throw a dart at a dartboard. all comes down to the aerodynamics (Ballistic coefficient) of whatever projectile you are slinging. ballistic coefficients are actually the ability of an object to overcome air resistance during flight. and those ballistic coeffieients are inversely proportional to the slowing of the object. (in lament terms, the higher the number of the BC, the better or less affected by air that object is) =) Im pretty handy with graphing calculators if you want to see some visual data. I always got extra credit in my algebra and trig and calc classes for doing visual demos (with ballistic data) for my classes. =)
-
Visual PLEASE, when you have time.
And, thank you for that explain of BC
-
I did do a quick search on BC and see where speed is an independent variable in most formulas. They also say that the constant (G1, G2, etc) is assumed for certain projectiles, etc. I'm wondering how a waisted pellet fits into some of these calculations? Is a specifically tailored BC calculator needed? Anyway, even without a BC formula, it has been known for a good while that the standard pellet shape does not do well as it approaches the speed of sound.
Here's something that also needs to be taken into consideration, and I add it to this thread because someone recommended wadcutters are being sort of "all-around" hunting fodder. Wadcutters can display some great accuracy at short ranges, but seem to fall off after twenty/thirty yards. At "mid" to long-ranges, a lot of hunters prefer domed pellets. So you need to find the pellets that work best at whatever ranges you are shooting. Pellet hardness can also be important. As I mentioned here or elsewhere, a soft wadcutter driven at high speeds (close shots) has been known to do only superficial damage in head shots taken on medium sized game (i.e. raccoon).
-
You also have to remember all this "bucking the wind" talk is only referring to dead straight into a consistent wind. With a side wind of any kind the .177 and .22 react about the same. Very seldom can you reproduce hunting shots going straight into the wind. You also have to compensate for gusts and multiple or swirling crosswinds etc. I guess it is like a larger kite just catches more wind while a smaller kite catches less wind but is effected more by it.
The major factor to be considered in a crosswind is the Ballistics Coefficient.... The amount of wind drift is proportional to the DIFFERENCE in the time of flight between the real world and in a vacuum.... There is lots of information about it on the internet from bullet manufacturers such as Speer , Hornady, and Sierra.... The BC for a given shape is proportional to the Sectional Density.... Larger calibers have a greater SD.... The advantage in BC for similar shapes will always lie with the larger caliber....
Bob
-
Interesting discussion about penetration comparison between .177 and .25 cal here....
http://www.gatewaytoairguns.org/GTA/index.php/topic,14841.0.html (http://www.gatewaytoairguns.org/GTA/index.php/topic,14841.0.html)
Just another part of the puzzle.... I didn't see any specific numbers for the .177 and .22 cal Mod. 48s in this thread so I went to Straight Shooters and found that the .177 with a 10.5 gr. pellet and the .22 with a 14.5 gr. pellet shoot about the same velocity ~850 fps.... Using ChairGun's penetration calculator that gives 4.23" for the .177 and only 3.73" for the .22 cal.... Even though the .22 cal has a LOT more energy (~23 FPE vs ~17 FPE).... The .177 with heavy pellets can outpentrate "normal" weight pellets in the .22cal.... Of course if you go to heavy pellets in the .22 cal then that changes....
Now I can see the logic in using heavy pellets in a .177 for game as large and tough as raccoons providing a "fusebox" shot is taken.... Just goes to show that "Impact" can mean a lot of different things.... It also shows I'm always learning.... and have lots more to learn yet.... ;D
Bob
-
Yep, not sure the title was worded right, and not sure the question was asked properly, but the answer is showing it's face little by little....
Thanks for more input Bob.
-
for serious hunting I really like it to be going 900 to 950fps.
I agree, although if I have to for accuracy I'll allow 850-950 fps.... Since I shoot mostly PCPs I can achieve that velocity range in any caliber up to .25.... Most of my hunting rifles are .22 cal.... as that's big enough for most of the game I hunt....
I do have one exception.... My most used hunting rifle is a .22 cal PCP Carbine that I use for Grouse hunting.... It shoots 18 gr. JSB Exact Heavies at 700 fps (20 FPE) and it's absolutely DEADLY with head shots.... most of the time knocking the bird off it's feet.... That's one specific case where I prefer the momentum of the heavy pellet more than the extra velocity with a lighter pellet....
Bob
-
Great thread. I wish I knew how to subscribe to it.
To back up what Bob has been saying, here are some hard numbers, from the Diana 48 that is often mentioned. I'm not sure if they were calculated (likely) or measured, but I bet they're accurate.
http://www.straightshooters.com/ourtake/ottest48.html (http://www.straightshooters.com/ourtake/ottest48.html)
They have similar tables for the few guns they do sell.
Maybe this goes without saying, but the intended use can make the .177 "better" than .22 or .25. For instance, if I'm wanting to do plinking on a budget, .177 is better, because ammo costs 1/2. .22 airgun ammo costs about the same as 22LR firearm ammo. 22LR has a huge advantage vs. .22 airgun ammo, so at that point, the only advantage to shooting .22 from an airgun is when airguns are allowed and firearms aren't. Or, if one is worried about overpenetration.
Another point is that if the .22 won't penetrate into the body of what you're trying to hit because of its larger diameter, it is less ideal. One needs enough energy to get to the guts.
Making head shots on ground hogs at 85 yards, out of a .22 springer... I would have to see that to believe it. Someone in this thread says he does it.
-
My three cents on the subject. (Already kicked in two. ;D) In most cases, either caliber will do fine. Now, how in the world did people hunt with air guns back in the early 70's, before the proto-magnums like the FWB124? Guns were shooting in the 700's (.177) and 500's (.22) but they still took game. Go figure? Everyone wants their air gun to be a .22lr - or better!!!- these days. It's funny to see posts from folks who just bought a Diana 45 or even a 35 or 27 and they talk about how accurate they are, what a great hunt they had, easier to shoot, etc, etc. Yes, you have to give up a bit on the range but that's all part of the game. You can still stand pretty far off and take game. This is not like you will be hunting rhino on the Serengeti where poor performance will equal your last. ;) Just about any of the current models in the magnum to ultra-magnum classes will get the job done, in either caliber. And you really can't judged performance by the stats, alone. Much of the proof still lies in the pudding. And that's another fun part of the game. Unless you are totally dedicated to bench rest shooting, etc, you might not want to over-think things. Consider why you are getting into the sport in the first place.
Like I said, I happened to buy a nice 54 in .177. Now, today, I would likely hold off for a .22, but I'm still not complaining. Both will "get the job done". And, sometimes, less is more, as they say.
-
I bet you most women won't agree with you on that one! LOL!!!!!!!!!! :P
-
Are you suggesting thoose with .25 cals are compensating! I like .22 all around, more forgiving I find, if I was 1/2'' out, more often than not it did not matter, and I assume that near misses are less effective in .177. But my opinon can't hold much, I have never owned a .177, not even in my pb's , I find the hmr's far to pricey.
-
And I understand that past 150 yards the 17hmr's performance really drops, I am consistantly able to take gophers at 160 with my 10/22
-
Another vote for the .177 if set up right. Just from observing penetration in various calibers both in game and target i'm really thinking more and more that the limited output of a springer works best with light solids(for hunting), striving for maximum penetration rather than impact of ftlbs. Very similar to the preferred use of 7x57 and 6.5x55 mausers on elephants by professional hunters in the early 20th century. They used solid projectiles and went for brain shots. I'd venture to say, that if you took their powerplant and rebarreled the mausers for the larger 8mm or larger slugs, they didn't get enough penetration to drop the beasts. There was a reason they found those light calibers effective. Penetration. I have never had a critter run off yet that had 2 holes in them. Most of my .177 shots have had both an entrance and an exit hole and those are the ones that, coupled with a headshot, literally go limp and drop. Can't ask for any better than that. J
-
Have some of you guys heard about "Hawke Chair Gun" ? its free from the Hawke website if you sign up. It has the entire database of pellets .177 to .25's in there, it calculates the POI, balistics, ..... pretty much everything you want. graphs it and puts it in tables. It also has a bunch of other super useful features. Im not trying to sell yall this software.. but I am just very impressed by its performance! Check it out, youll learn a lot by just tinkering with it.
-
Deleted