Seems like folks around here find a gun they like and adjust the pellet by weight to get the speed they want. Like buying a steak by thickness to cook it for the time you were going to cook it already.
Mexy, most of us here, I think, have very little interest in the highest
July 5 2008, 1:50 AM
fps question from a practical point of view.
The problem is that the highest velocities are attained with the lightest pellets. The lightest pellets have never been shown to have practical accuracy at the highest attainable velocities. Therefore, regardless of how high a rifle may be able to shoot, knowledgeable shooters tend to find good heavier pellets that bring the velocity back down to about 900 fps or less. Two things are achieved; the energy and momentum of the pellet becomes greater and the accuracy and precision improve. There are sound reasons for this.
These lightest of pellets also have very poor ballistic coefficients and shed their velocity at a great rate. Thus by the time they have traveled sometimes as little as 20 metres, they have lost a lot of their energy and velocity and are already slower than a more appropriate pellet and have less energy for penetration and killing power in hunting. So discerning shooters stay away from very fast light pellets. Think of shooting tiny beads from a slingshot as against a better bigger stone; or throwing a tiny piece of gravel as compared to a baseball.
Unfortunately some of the air rifle manufacturers depend upon especially young and impressionable folk being turned on by claims of very high velocity for their rifles. What an experienced shooter tends to do is to decide what he wants the rifle for and then select, or seek advice about, the rifle and pellets that will meet his requirements.
If that explanation is of little value then all I can write is that there is no one particular rifle because many have the power to blast the lightest of pellets to highly inaccurate velocities for relatively short distances.... Kind regards, Harry in OZ.
Matter of fact I only said to Wendy a few days ago that now the water restrictions from our drought have been lifted a little I might set the tank up again ( or rather a new one ) as I have a couple of things to do .
Hey, I even think you may have been impressed by that tiny group shot at 43" underwater HEHE! ...... Kind regards, Harry.
today, I spent an hour firing my gun with a stethascope banded to the lower receiver while sliding a tuning weight around on the barrel. Nothing conclusive ... the gun was in a fair benchrest setup, firing over a chrono an making little groups at around 25yds.
Only practical thing was the confirmation that tho the sound changes near the end of the charge, the impact stays the same until velocity changes beyond predicted limits. I can hear this change well enough without the stethascope, and I never did figger out if I had the BEST spot for the tuner.
I have a rws model 34. I had it "de-tuned" and now it is out of this world for smoothness and accuracy.Cocking is much easier and all twang is gone. It was shooting way too fast, and now it shoots CP's at around 760 fps, which to me, seems what this rifle was really made for. I also had my 460 22. cal detuned and now it is a great gun that I can now shoot all day.
OK, then here is Steve NC's take on the maximum speed the air can reach...
July 5 2008, 8:40 AM
... so discount that a little for the practical limits of a very light pellet and you have some kind of an answer.
"Steve in NC
Correct about ~1650fps being the max theoretical velocity anywhere...
...in the gas flow path, but incorrect about it being possible for flow in the port to be faster than flow at the muzzle.
It's not possible - at least not in any practical sense.
That's because the only way velocity could be higher at the port than at the muzzle would be if the pressure at the muzzle were higher than at the port.
Pressure represents the potential energy of the gas, while velocity is kinetic energy. If the latter goes down, then the former must rise, and vice versa.
The law of conservation of energy makes it so.
Steve"..... End quote.
LD has stated that he has shot to approximately 1450 with the very light Hobby RWS pellet.......... Kind regards, Harry.
You could drill the heads on 5 grainers and maybe get them down to 4 grainers. How about ignoring actual pellets and shoot Quick Cleaning wads.
If all you're interested in is generating Savage Data I think your questions will fall on deaf ears.
Marketing gets newbies wound up about speed but Velocity is just a Number. Energy is much more useful as you can compare different calibers for initial impact results.
Velocity is like Horsepower. It isn't nearly as important as tourque but it is what they sell cars on because newbies look in that direction.
Gamo knows this and prints data with 5 grain PBA pellets which is ridiculous for real shooting but gets the newby going with 1500+ FPS speeds.
Fact remains Airguns are subsonic beasts when working best and when trying to push the speed envelope the accuracy thing and the impact thing must be ignored to determine what is speedwise Best.
GET OVER IT! It doesn't matter. What works best is something around 925 with an occasional surprise that works in the transonic region above 1000 FPS. The rule is go Mach .82 or less and you'll get the best accuracy.
Speed is just mindless data meant to impress the neophyte that knows of nothing else to compare things by.
Well I don't have a .177 but here is a sizzling 11.9 g .22 shot
July 5 2008, 7:08 PM
Well was fooling around with my modified .22/.25 Condor PCP and here is a 11.9 grain .22 pellet fired from a 24 in barrel, 2600 psi fill, 90 gram custom brass hammer, polished inside frame, BUT remember much past 1000 fps a pellet is useless for accuracy.
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