steamer scribed in
:

--I'm trying to figure out what might serve as an effective
backstop for my 20mm cannon. Strictly black powder and muzzle
loading mind you, but what would it take to stop something coming
out of that barrel so's I don't scare the bajeezus out of the
neighbors?

don't fire anything heavier than a pill bottle and you have no
worries (-:

but seriously....something large and light for it's size will stop
pretty quickly by itself, like a shotgun shot cup (I've found them on
the local .22 only range), even more so if it is not aerodynamic in
any way.

any kind of solid ball will take a fair bit of stopping I'd say. at
least 3/4" plate at 45 degrees to deflect it into sand. might take
more. but can you be sure of hitting it?

--
swarf, steam and wind

--
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