200yards

[baz]

The speed of sound changes with altitude I am told

Usint a .25 with heavy pellets at 1130fps you have a LOT more chance of achieving reasonable accuracy at 200yds and enough energy to smash a bottle than the one in the film

I think hes a max of 120yds from the target, still pretty good but a LOT different to 200yds as the pellet will be dropping like a mortar after 100yds, as it does on a .22 rimfire

I have shot tin cans at 300yds using .22 rimfire and subsonics, but it was on a dry field so bullet splash was easy to see (and richocets!) the holdover was quite a few feet but I cant remember how many as it was years ago

All good fun though

[johan_portin]

The speed of sound changes with altitude I am told

Who ever told you that need to do some reading, cuz its bull. Sound is not dependent on pressure, just temperature!

But it’s a common miss conception since its normally colder at higher altitude! Doing the math on this, the post Robert .22 posted earlier is not wrong if he shoots at 35 degrees Celsius. The speed of sound increases with temperature.

[Gary C]

Who ever told you that need to do some reading, cuz its bull. Sound is not dependent on pressure, just temperature!

But it’s a common miss conception since its normally colder at higher altitude! Doing the math on this, the post Robert .22 posted earlier is not wrong if he shoots at 35 degrees Celsius. The speed of sound increases with temperature.

SoS through a medium is dependent of Density. Greater the density the faster the SoS. My first degree, plus post grad qualifications, was in surveying and this is one of the basic concepts of underwater survey. In terms of air, unless I am mistaken, Air is less dense at higher altitudes therefore SoS will be slower, therefore Baz is right and you are wrong.

A cursory glance shows:

http://en.wikipedia.org/wiki/Speed_of_sound

[baz]

SoS through a medium is dependent of Density. Greater the density the faster the SoS. My first degree, plus post grad qualifications, was in surveying and this is one of the basic concepts of underwater survey. In terms of air, unless I am mistaken, Air is less dense at higher altitudes therefore SoS will be slower, therefore Baz is right and you are wrong.
[/URL]

Aint as daft as I look then

[Ka-Boom!]

Aint as daft as I look then

Actually, you might be...

Speed of sound in air is only linked to temperature. Speed of sound in other mediums is a whole load more complicated!

[Gary C]

Actually, you might be...

Speed of sound in air is only linked to temperature. Speed of sound in other mediums is a whole load more complicated!

Interesting but superficial. Just because the author of this piece says ignore altitude doesn't mean he is literally correct. You ignore altitude because you are using Rho, air pressure. The reason that altitude has an effect is because of the change it has on Rho. If you have already measure Rho then the altitude that Rho is measured at is irrelevent.

If you don't have Rho, and are making a calculation, then you will need the altitude to be able to make it.

http://en.wikipedia.org/wiki/Density_of_air

[baz]

What Gary said

[Ka-Boom!]

Interesting but superficial. Just because the author of this piece says ignore altitude doesn't mean he is literally correct. You ignore altitude because you are using Rho, air pressure. The reason that altitude has an effect is because of the change it has on Rho. If you have already measure Rho then the altitude that Rho is measured at is irrelevent.

If you don't have Rho, and are making a calculation, then you will need the altitude to be able to make it.

http://en.wikipedia.org/wiki/Density_of_air

Sorry, I still don't agree. I can't find any reference to pressure or density (P) being relevant to the speed of sound in air. During my training, I remember being specifically taught that is was purely dependant on temperature.
This page sums it all up quite nicely.

[baz]

Actually, you might be...

Speed of sound in air is only linked to temperature. Speed of sound in other mediums is a whole load more complicated!

From that you could say that no matter how far from target the trajectory would remain the same

Gary is pretty clued up on this subject but I admit I aint