I think eley force is as close as we will come to high velocity match ammo these days, and even that requires some luck.i have had some fairly impressive results with cci select , but not many other folks like it. Federal 719 has been bad for me here. Geco semi auto at 1148 fps shoots decent in our rifles. Some of the biathlon ammo is very accurate but velocity is barely over 1100 fps
Quote:
Originally Posted by CamP
I love Eley Force. I searched high and low for an accurate round that would knock over heavy rams in metallic silhouette. Force is the only hv ammo that consistently produced tight groups.
I got to admit it ain't bad. But it can vary on it's consistency. Here was a few of better ones I shot in my backyard shooting prone.
I have lived in Idaho and Washington and during that time shot XTC, Mid-Range and Long Rage matches in AZ, NV, OR, ID, and WA so I am familiar with the wind.
Evidently the shooters I known and shot with over the last 35 years were not progressive enough even though they won at the Regional, National, World Cup and Olympic levels. Perhaps what they really required was to "think outside of the box" which I can say with great certainty will be news to them and their peers.
jaia, your posts are characteristically fact driven, and your choice of words and phrases seem carefully chosen (unless you're heckling one of us... well, even then) so that your arguments are worthy of a careful read. I've learned a lot from threads like this one - thank you.
For our purposes, the speed of sound is a predominately a factor of temperature, rather than air density (or, elevation, if you want to read it that way). This one has potential to confuse some readers, and might have been more accurate to say "Mach at 70 degrees Fahrenheit is 1128 fps".
That's why some of our cold-weather shooting friends will hear sub-sonic rounds crack on cold winter days, but not during the summer.
respectfully, 'tool
CORRECTION: Should have read "Mach at 70 degrees Fahrenheit is 1128 fps", not "Mach at 59 degrees Fahrenheit is 1128 fps", so I fixed that phrase. It's 1116'ish fps at 59F.
Last edited by Airtool; 12-06-2019 at 11:57 PM.
Reason: I did it wrong!
I must be misreading the formula somehow.
Doesn't density affect propagation rate?
Lessen density widen the gap between molecules, slow the rate?
Pressure and temperature affect density?
I believe where sound is readily transferred which may be nearing a vacuum?
No difference in speed of sound at different pressures, only temperature affecting sound.
Quite possibly "intensity" and speed are separate and different from each other?
I remember the bell jar test we did in school increasing vacuum as a wind up alarm clocks bell was ringing. Lowered intensity yes but was the speed any different?
I must be misreading the formula somehow.
Doesn't density affect propagation rate?
Lessen density widen the gap between molecules, slow the rate?
Pressure and temperature affect density?
No pressure = vacuum = no sound
Near vacuum allows only weak transfer of sound.
I'm so confused....
According to Sierra Infinity v.6 (external-ballistics program), and using a Sierra #1380 SMK (69g) leaving the muzzle at 3,100 fps, the results are in the chart below:
I don't get this either. As shown below, air density obviously DECREASES as altitude increases, and density also obviously INCREASES as temperature drops. So density affects the velocity of the bullet, BUT NOT the speed of sound. Go figure...
I suppose the difference lies in the fact that air RESISTS the passage of the bullet, but ENABLES the propagation of sound waves...
This come up all the time. air density is not part of the equation. People assume that as altitude increases, temperature drops and SOS increases. I live at 7000 feet and at 70 degrees, the SOS is the same at 0 feet. If that weren't true I would not be able to use match ammo because it would all be above the SOS. Yes air density does affect the bullet speed but not the SOS.
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