RE: [SG] Shotguns

A few comments to Binhan Lin's post:

>The answer is yes.  The next question is - is it useful?
>
>The answer: maybe.  In general a shaped charge will penetrate at least
as 
>much RHA as it's diameter.  Advanced explosives, metals and shaping 
>patterns can vastly improve on this. So a 20mm HEAT will penetrate
roughly 
>20mm RHA.

You seem to have forgotten the "can vastly improve on this" bit you 
mentioned in the previous sentence :-/ In an explosives course I
attended 
some years back I hand-made a 1" diameter HEAT warhead which managed an
RHA 
penetration of almost 40 mm when we tested it... and I certainly didn't
use 
any very advanced explosives etc. <g>

As a rule of thumb modern HEAT warheads today have an RHA penetration 
around 5-7 diameters; the best I've heard of penetrate ~8 diameters, and

recent research suggests that 10 diameters should be quite achievable 
within the not-too-distant future. (The abstracts for those research 
reports are open source, so I'm not disclosing any secrets here <g>)

>With mixed ceramic/metal armors (Chobham)

Chobham is one specific type of composite armour, but there are lots of 
others as well.

>shaped-charge warheads are much less effective, which is why tank guns 
>usually use APFSDS

While the composite armours are very effective against HEAT, the tanks'
use 
of APFSDS has at least as much to do with accuracy as with penetration -

the APFSDS is much faster, with a much flatter trajectory, so hit better
at 
medium ranges.

>and AT missiles have big (8" wide) diameters and now, double HEAT
charges.

Tandem charges are there to defeat reactive armours, not composites.

>You might be able to squeeze an APFSDS into a shotgun shell, although
to 
>get the velocity necessary you'd have one heck of a kick.

Depends on how heavy the round is and how fast you want it to go, though
- 
the 1500+ m/s muzzle velocity isn't part of the definition of APFSDS :-/

Later,

Oerjan
oerjan.ohlson@telia.com

"Life is like a sewer.
  What you get out of it, depends on what you put into it."
-Hen3ry