"Paul F Austin" wrote in message
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"Kevin Brooks" wrote in message
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"Harry Andreas" wrote in message
...
In article , "Kevin Brooks"
wrote:

"Harry Andreas" wrote in message
...
In article , "Thomas J.
Paladino
Jr." wrote:

snipped
(Knew most of this)

All shooting ranges in the US (and NATO) have stopped using
heavy-metals
in
all of their training rounds (including small arms). DU was
never
used
as a
training round to begin with because it is too valuable. The M1
sabot
practice round uses a steel core and behaves exactly as the live
round
would.

Interesting. As a re-loader, I'm curious how a steel core
replicates
the
sectional density and ballistic coefficient of DU and therefore
the
ballistics
of the round? After all, DU is about 2.33 times the density of
steel
(I
used
values for Maraging steel, but 300 series is the same, and higher
than
alloy steels), so to keep the same mass the round must be bigger,
but that would degrade it's areodynamics.
Can you elucidate? I don't understand.

It does not have to. When firing the training rounds from the M1A1,
the
ballistic computer is set for the APDS training round, just as it is
set
differently for the HEAT round vice the DU APDS-FS--the computer
adjusts
the
aim point accordingly.

Just so.

Maybe I didn't snip enough, but he said, "exactly as the live round
would."
That's what I was questioning.

Frankly, I would expect a change in ballistic performance, culminating
in an adjustment of the sights.

You are probably right, hence the different settings of the ballistic
computer. I guess you could develop a matching training round if you
really
wanted to; the lighter composition of the dart could be compensated for
by
changing the diameter, length, etc. I don't know why anyone would want
to,
though, since the training value is still there with the dissimilar
rounds
as long as the ballistic computer is correcting for the differences,
meaning
no perceived difference to the gunner.

I've read that the training darts include a pyrotechnic that deploys drag
features after about 2Km of flight so that smaller ranges can be used. Is
there anything to that?


Yes, the sabot practice round is indeed range-limited, however not through a
pyrotechnic (as far as I know).

The M865/E2 is the current sabot training round, and it uses a slotted tail
cone instead of tail fins on the projectile in order to limit its range.
Performance-wise, the round itself is 'functionally indistinguishable' from
the live round, in that the round weighs, looks and feels the same (for the
loader) as the live round, and it will fire and travel the same as the live
round as well (for the gunner). The only difference from the crews point of
view is the range. Beyond that, they work with the training round in exactly
the same manner as they would a real one. The M1 computer systems will
compensate automatically for any ballistic differences between the two
rounds, so the crew will not see any major difference while training.

More info on the subject:
http://www.globalsecurity.org/milita...tions/m865.htm