13-05-2005, 11:32 AM
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The message
from (Nick Maclaren) contains these words:
1000 fps is correct
I reread my post, decided to check my facts, and cancelled it :-)
Unfortunately, Usenet is not good at that. I still can't make all
the figures add up, as I am pretty certain that 350 fps was touted
as the maximum velocity for a 0.22 air rifle when I bought mine.
That is under a quarter of the energy of yours (and pretty damn
inaccurate).
350 fps is a bit less than 240 mph, which is 'nosedive' speed for a
bullet/pellet.
I'd estimate that a reasonable (·177) air rifle should propel a pellet
at around 900 fps, a good one, a lot faster. If I were to 'get at' my
·22 AirArms S310, I reckon, getting it to hold a pressure of in excess
of 250 bar and using a light pellet I could bump that up to over 2,000
fps - but then, it would require a f.a.c.
One thing to do is to check what those idiots mean by foot-pounds,
because there are at least three obvious meanings, and doubtless
others known only to legislators. Remember BHP?
A foot pound is very precise, and is that amount of energy required to
shift the mass of one pound the distance of one foot - but how you would
measure it in the 'back garden lab' I don't know.
I'd hazard a guess that you'd hit the bottom of a metal weight with the
pellet and see how far it rises against the force of gravity, and work
it out from there.
Ideally, the weight would be in a vacuum and not subject to friction on
its way up, and having come to rest, would remain there, but...
--
Rusty
Open the creaking gate to make a horrid.squeak, then lower the foobar.
http://www.users.zetnet.co.uk/hi-fi/
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