According to bighead :
Thats not correct. Smokeless powder is not an explosive, it burns
very fast and when it is confined has explosive properties due to the
rapid expansion of gases. Blackpowder, on the other hand IS explosive
and needs no confining to make it so.

Sorry, wrong.

_Neither_ smokeless powder (eg: pyradex) or blackpowder are explosives.

["Explosive" being defined officially as when the gas expansion is
above the speed of sound.]

The difference between gunpowder and smokeless powder is simply that
gunpowder's coefficient of combustion is such that it burns _very_
fast even if uncontained - but still not an explosive shock wave.

How fast depends on the grain size (primarily). Antique firearms
usually use FFFFg (very fine) or FFFg (fine). Antique firearms
simply don't work properly with coarser black powder.

The only way you can get blackpowder to "go boom" is contain
it inside something like a pipe with threaded on ends. Then you're
getting the boom from the pipe overpressuring and throwing bits.

Pyradex, when unconfined burns fairly slowly comparatively.

A hand full of smokeless powder
can be touched off with a match and will only burn, admittedly very
fast and you may loose some eyebrows, but a hand full of blackpowder
would take your hand off when a match touched it.

Sorry no. Blackpowder does the "flash, lose eyebrows" trick[+]. Pyradex
uncontained is _much_ tamer. More like safety matches burning.

The only way you can get firearms to work with pyradex is to contain
it to build pressure, then it burns much faster. Blackpowder burn rate
doesn't depend nearly as much on pressure.

If blackpowder was an explosive, you couldn't make rocket motors with it.
You couldn't use it in a firearm (it's a little late to find that out
now ;-)

The chinese started flying blackpowder rockets around 1000AD.

Kids fly model rockets with blackpowder motors (ordinary ESTES model
rocket motors) every day.

I fly amateur rockets (I'm certified to motors that can throw a 25
pound rocket 3000' up). While the fuel grains themselves aren't blackpowder
(AP actually), we used blackpowder to pressure-eject the recovery system
(usually a parachute).

If blackpowder was explosive, the rocket would come down in itty bitty bits.
Which can ruin your whole day.

We generally don't use pyradex (despite it being a lot easier
to get these days) for ejection charges because when used as we use
blackpowder, it produces gas too slowly. To use pyradex, you have
to try moderately complicated containment methods that let pressure
build up high enough to get the burn rate fast enough, and then let
the pressure out without blowing a hole in the rocket.

[+] A friend of mine lost his eyebrows and got a free facial peel from the
flash when he got a little too close to a teaspoon of gunpowder set off in
a dish. The dish survived. Only slightly melted. If blackpowder was
explosive, the dish would be in itty bitty bits. My friend survived
just fine too. Lost some acne scars in the process... Some people pay
a lot of money for that process... ;-)

The most common method and one we used when was working on a pipeline
is ANFO.

Do note that getting ANFO to work _properly_ requires care in selecting
ingredients (beyond simply the right chemicals), mixing ratios, etc.
McVey tried for quite a while before he got it right.

Secondly, ANFO is difficult to set off. One of it's great attractivenesses
is that it's very stable and safe to handle. If you light
it, it just burns. Like the fuel oil it contains. You need a pretty
violent shock - a blasting cap (or even a stick of dynamite) - to make
it detonate.

ANFO is great for large scale application. They carry it around in pumper
trucks on large quarry sites, and just pour it down the holes. Insert
blasting cap, insert a wad of something to seal the hole, and fire the
cap.

For a onsey-twosey remove stump job, hiring a contractor to come by
with a couple sticks of dynamite is a lot more effective.

But trying any of these is unsafe and probably would earn you a
comfortable stay in a warm place with 3 meals a day, hospital or
jail.

Very unsafe. The prison term is when you manufacture explosives without
a license. Or store it without a LEUP. Plus violating local ordinances
about permits etc.

[As I understand it, and perhaps still even now, I'd merely need to go
to the Ontario Provincial Police, say "I want to blow up three stumps
at this address at such and such an address", they give me a permit (if
they think what I'm doing is reasonable), which gives me permission to
purchase the appropriate number of dynamite sticks, and then I can set
the stuff off myself as per the permit. Without having a "license"
per-se. But the SO won't let me, so I've not gotten to test my
understanding... ;-)]
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.