pressure 22air vs 22LR
Hi, can anyone tell me how is it possible that a .22 airgun (modified condor for example) can shoot almost at same velocity (1100 fps and more) as 22LR when using same 40grain bullets. The pressure which airgun operates is 2000-2900 psi vs pressue in 22lr chamber is arund 22000 psi. My guess would be that when bullet travels down the barrel airgun gives that 2000psi all the way to the end vs 22lr gives this 22000 psi only at the beginning, am i on the right track?
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I think you need new Avatar
Holy Crapola…. that looks just like me :)!!!!!
LOL
Thanks Adam!!!!!
how about them numbers eh?
The Vulture Has Spoken….
I think you need new Avatar
As stated in the post above the results:
using multiples of 14.3 grain Crosmans.
Allows the use of cheap pellets to determine power.
Walter….
For those like me that are not in the know, where does one get .22 pellets that weight 42.9 grains?
3,000psi air
42.9 grains
1050, 1032,1031,1021,1007
pressure at 2650psi
28.6 grians
1162, 1155, 1149, 1143, 1129
pressure at 2400psi
14.3 grians
1401, 1391, 1381, 1372, 1371
pressure at 2200psi
42.9 grains
948, 942, 935, 930, 923
24″ barrel, heavy hammer ? 120 grams IIRC, the original three port valve
no valve spring, tophat at 0.200″ 800cc tank
The Vulture has spoken!! (produced some numbers for you 🙂 )
Walter….
How about the parameters be:
.22 cal
any weight,
any valve,
any hammer
any spring
24″ barrel
only on air to the pressure rating of the vessel/tank
Let’s see where we can go doing this 🙂
I brought along my .22 barrel today and I’ll get some numbers for my Vulture as a baseline.
Going to use multiples of 14.3 pellets to see what can be done
So….. 28.6, 42.9, 57.2 grains from a 3,000psi fill.
Gonna be fun, eh fellas:)
Just and FYI, the Hornady .17 VMax bullet has a BC of .185. Dreadfully low, because of it’s low sectional density.
Interesting test to find optimum length in a 17M2:
http://www.shootingtimes.com/ammunition/stmach2_032706/
This article shows that depending on the load and the gun, around 18″ is optimum for a .22LR, where in a .17M2, 19 to 20″ due to the lower expansion ratio.
What I’m gathering is that is should theoretically be easier to get our airguns to shoot a .17 bullet at insane velocities than it will be to get a .22 to shoot modest, yet unattained, velocities.
But now I see where the challenge is. Push more air, longer, to overcome the larger bore diameter and consequent expansion ratio, and give the barrel the length it needs. To my mind, a longer barrel would be key to starting the collection of data. Using a 24″ barrel doesn’t seem like it’s going to put us where we wanna be.
I need to put my maff hat on, but maffs is hard.
Is there not some point in an airgun barrel where the velocity of the round exceeds the ability of the rifling to spin it? Causing the round to skid over the rifling instead of spin with it? Presumably this is why live rifles have a different twist ratio to their rifling??
The more I think about it, the more I feel that this whole thing is purely academic. If I want hard hitting long-range power, why would I NOT chose a .25?
The answer to why 40grainer is going 1235 fps and the 17grainer is going 2100 fps when shot out of the same rimfire cartridge with same amount of gunpowder used and why for airgun it doesn’t work like this is simple.
There are actually two reason for that:
One:It’s beacuse the expansion rate for air at the temperature what airgun operates is so much less than expansion rate for gases at the temperature created by burning gunpowder. Air is not capable of pushing the projectile 2100 fps at normal circumstances.
Two: As .17 is smaller caliber than .22, the pressure in .17 chamber is much more consistent all the way to the end than for larger caliber .22 and therefore gains more velocity. For airgun it does’nt matter if the caliber is .22 or .17, the pressure stays pretty much the same for both of them, of course if the valve is tuned to the maximimum tank pressure in both cases.
One thing i just started wondering about is that if 22lr gains 140 fpe with same amount of gunpowder used as in the .17HM2, which gains 166 fpe, it seems that .17 is more efficient caliber than .22 for the cartridge?
…it makes me belive that my helium experiment with .177 caliber along with 21-30 grain bullets might be promising after all:D. I’m not hoping for better energy compared to the .22 , but if the walther barrel with 1/16 twist can stabilize 20 or 30grain .177 bullet i belive i would get flatter trajectory when using .22 and 40 grainers. I think the longer 17 bullet would also give better BC with same weight, but shorter .22 bullet. Only problem might be the accuracy because of the relatively low twist rate(might need a faster twist rate barrel), but w’ll see.
Regards,
Alari
The reason Chad i would suspect is that bullets tend to be far superior for retained long range energy. You could argue that a .25 40gr pellet with say 80 FPE will retian 30FPE at 150 yards buit i can say with confidence a .20 30 Gr bullet at around 1200 FPS will still be close to 1000 FPS at 100 yrds dropping to around 880 at 150 to 200 yards. i used chairgun ballistic software to calculate retained velocity and drop with hornady Vmax bullets at air gun velocities.
Pellets are pretty good at short to medium range, but there is no way anyone can tell me they are getting consistent hits on rabbit sized animals at 150 yards, pellets are just not accurate enough. I suspect a .20 or .17 bullet of around 20 to 30 gr would be far superior at 1) handling supersonic flight and 2) accuracy and wind deflection not to mention bullet drop.
Check out the Chairgun ballistic program and compare a 30 gr bullet V a 28 gr eun jin at 1050 FPS.. after 75 yrds its no contest, bullet kills the eun jin.
Something just occurred to me. And please, someone correct me if I’m wrong. We’ve all heard about the .17HMR, a .22 mag, necked down to use a 17 grain .172″ Hornady V-Max bullet. But it’s little brother, the .17 Mach 2 is a .22LR necked down to the same bullet. What I’m unclear about is this: Is the Mach 2 identical in every way to a hi-velocity .22 long rifle, except for the .17 bullet? Is the powder charge the same ? My speculation is that a .22LR 40grain at 1235fps (CCI Mini-Mag) equals a .17M2 17 grain at 2100 fps. All are equal except bullet weight. Conversely, if we want to shoot a 40grain .22 air gun at 1235fps, it would have to be capable of shooting a 17 grain at 2100. I don’t know about YOUR gun, but mine ain’t nowhere CLOSE to being able to push a 16 grain pellet to 2100, much less a 17 grain pellet. But the question is how far south of 2100 fps is mine capable of with the proper barrel length. It would be fun to run a few thru an extra long barrel, just to see.
The more I think about it, the more I feel that this whole thing is purely academic. If I want hard hitting long-range power, why would I NOT chose a .25?
well guys, just arrived in the states yesterday, and brought along a 25 inch wmr barrel, machined to fit an airforce airgun. got 270 metres per second with a 41.2 grain bullet on a STOCK 2007 model condor valve and stock hammer plus condor hammerweight. so yeh, i do believe it’s possible; met another guy in the netherlands who managed to get 105 fpe out of a heavily modified fire201 with a 22lr barrel. Once i’m settled here i’ll get a condor and do some more testing, as i got some untested costom valves with me. this will be in about 3/4 weeks from now hopefully.
Why don’t we turn this into a group project, instead of a sandbox filled with conjecture, speculation, and nay-saying. Define the goal: 1100fps with a 40grain .22 caliber projectile, with repeatable results. Now, what will it take to pull it off?
(1) some 40 grain projectiles
(2)?
What pellets are available in that weight? Would a polymer-saboted .17 HMR bullet work? Are there even .22 sabots available, much less ones that fit our barrels? Are there 40 grain .17 bullets? Does anybody know the math behind discovering the theoretical maximum velocity of the projectile? Likewise, how would I find out what can be extrapolated from a Kodiak flying at XXXX feet per second. If a 22grain Kodiak moves XXXX, what would a 23 grain pellet be reasonably expected to do? That’s what I mean by extrapolate. Is there any hard science or theory, or would anything short of empirical data be simply a SWAG, scientific wild-ass guess?
Who’d be willing to put their money where their mouth is, and in turn, trust others that have done likewise? What I mean is, would you feel comfortable pooling resources to buy some dedicated TAG forum-owned equipment, like a swaging die and some wire? We could nominate a willing participant to be the keeper of the goods, who would in turn be responsible for swaging the lead that the group buys, and mailing it to the participants.At our expense, obviously. Would a group-owned 30″ or so barrel be doable? Is there a practical way to share the barrel for testing with our individual powerplants? Would it do to also have a custom valve made and available for the group to share? Maybe it would be a good idea to compile a list of goods that could reasonably be anticipated to help further our goal of finding just where the ceiling is. That’d help figure the costs. How much would you pay to be a part of the project, and to further the art?
Set a goal that the project be completed or abandoned by, say, this day a year from now. At which point, the participants that ponied up money play some silly little game to decide who gets to keep the goodies we bought. Somebody would end up with some sweet toys, whether we get close to the goal off 1100fps or not.
I don’t know the answers to any of the above questions. I’m just tossing them out there to see what happens. But consider this: even if we fail to hit 1100fps, we’ll still figure out where the ceiling is at a given time in the evolution of airgunning. Wouldn’t it kick ass to put our heads together and work up a system that reliably pushes the slug to only 1075fps? I’d call that a glorious failure, and one that I’d be happy to settle for.
Let’s work the problem, and see what we learn.
For my part, here’s what I have to work with: a new-style Blodnob valve with a two-piece brass/delrin hammer of unknown weight (at least 95.1 grams, as it’s to heavy for my Dillon powder scale which goes up to 95 grams). I’ve got a stock hammer spring, and a Blodnob-supplied heavy hammer spring that’s a bitch to cock, and makes for about a 30 pound trigger pull. I’d be willing to say I’ve got way more powerplant than I’ll ever be able to use in my 18″ barrel. I know that it’ll send 16grains downrange at at least 1289fps, and probably some measure faster, with some tophat adjustment and restrictor removal.
Anybody interested in seeing what we can come up with?
Ok guys ive read with interest your posts and some of your views that 1100FPS is unachievable or has not been achieved yet with 40Gr bullets.
Here is what i have learnt from my reaserch and asking of similiar questions for the sickness that is a quest for ever higher velocities! Yes its a sickness, but a nice one.. 😉
Guys check out youtube and cozzicrash i think he calls himself. He’s a Kiwi shooter that has a modified talon shooting 1180 to 1200 FPS with 30 Gr Eley bullets!! There is video of him shooting over a chrony. he does some wild 200 Metre shooting with his gun, so already with 30Gr we can exceed 1100 FPS, now with his mods in a 24″ barrel not the 18″ he has, i think his gun would shoot very very close to 1100 FPS with 40Gr bullets.
Daved claims although sounding quite high are possible, I have spoken to Sean aka Blodknob regarding this very question and he seems to imply whithout actualy saying it ” UK laws kinda suck and he is being carefull” that Daved is not yet utalizing the full potential of his valve.
As far as my own testing has shown, well in my condor i run a stock hammer, but a larger hammer guide thing that sits in front of the hammer, dont know the exact weight but its almost twice the size of the old one. I recently machined a new valve stem for a spare tank that i damaged “the valve stem that is” and modifyed the ports so as they were more inline with the airflow. Preliminary testing over the Chrony has shown 1310 FPS with H&N Field Trophy and 1070FPS with Eun jins. All .22 calibre. I have also tried some pulled .22 subsonic ammo, which is way to tight for the bore but they fly out around 880 FPS one that was a little less tight in the bore clocked 1000 FPS, these are around 30 Gr as i cut the bullet off rather than damage them by pulling. They are lead not jacketed bullets and are sized incorrectly for the barrel. A proper sized 30 gr bullet will shoot at the same speed or very close to the eun jins. I have some ordered from Airguns of arizona but as yet dont have any idea when they will be shipped. When i recieve them i will post my findings.
Sorry to go off the topic guys.
Now back to topic, does anyone know why we can see above the speed of expansion/ sound in air guns? I have a theory that by reducing the valve mouth relative to the valve body, ie taper the airflow from the valve ports to tophat, this may increase the pressure of the air as the air is pushed at the same speed through the valve but has to compress the air in order to move at the same speed out of the valve.. Make any sense????
Like a water hose, i guess, tighten the water stream and the water velocity increases and you get a longer jet, open up the water stream and you get the same volume but at a slower speed less distance..
Does that help any explain my ramblings??
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As stated in the post above the results:
using multiples of 14.3 grain Crosmans.
Allows the use of cheap pellets to determine power.
Walter….
I had read that earlier in the post, but I did not think we had idiots that would try it.
Sorry, do not mean to be rude, I’ll leave that to you.
Have a nice day.