[livius]

The IRA has reduced the home made mortar to a science

So has FARC in Latin America. But then, I guess all these guys "trained" together at some point, anyway.

Thank you for that detailed explanation. I had a vague idea of what it was, but the specifics eluded me - until now!

[Prodigal Son]

Actually, that was the "For Dummies" explanation. If you want more in depth info- I'd be happy to talk your ear off about it ;-)