What the devil is a hand mortar?
The hand mortar is a weapon of the early modern period, one of the more obscure entries in the firearm family. It was invented in the late 16th century, was used sporadically for the next hundred and thirty years or so, and had gone all but completely out of use by the 1820s. It looks about like a blunderbuss which has had its barrel replaced with an actual small brass barrel, and it basically is what it says on the tin: a hand-held version of a mortar — id est, an artillery piece that shoots explosive shells.
The hand mortar shoots grenades.
Here's how it works: You take your grenade, you light the fuse, you start loading the hand mortar with gunp— hang on! You light the fuse before loading?! Yes. This is a logistic necessity since the barrel has to be rammed before the grenade goes in, lest chaotic events transpire; once the barrel is full of stuff, you can't put the mortar away to light the fuse. So: you start loading the hand mortar with gunpowder, first the flash pan and then the barrel, you stick in a wad of cloth, you tamp it perfunctorily with a ramrod if you like, you chuck the lit grenade in there — fuse end out, people! — you aim in the right general direction, you pray briefly but intensely, and... you pull the trigger.
Are you still here? Boots on feet, feet on legs, legs on torso, all bits in working order? Great! That means the grenade didn't jam in the mortar, the pan didn't go PFUT, the barrel was properly loaded with dry powder, and the firing didn't detonate the grenade! Now it's over there somewhere!
Perhaps it is evident at this point why the hand mortar is relegated to a parenthesis in military history.
Now, the bore of a hand mortar is in the ballpark of half the length of the barrel, so you won't be getting too good precision. That's okay, though; your throwing arm would in all probability be not much more accurate, and give you a poorer range — and besides, this isn't something you hunt quail with: it's a military weapon, and as such you will be firing it at whole groups of soldiers, most of the time. When you're firing at a 300-meter line of musketeers or dragoons, it doesn't really matter if a shot goes awry by a meter or five — you'll just hit some other poor sap. (This same principle underlies most of early firearm use, and indeed most pre-modern military use of ranged weapons in general.)
Where can I see a hand mortar?
Most of the time, this will probably be tough. Not many were ever made, comparatively speaking anyway, and I doubt if there are many of those preserved. If you're in London for some weird reason, the British Museum does have a nice specimen, but it's hidden away on the bottom shelf of a cabinet in some tiny out-of-the-way room, underneath several shelves of lace hankies, porcelain and similar non-hazardous muck.
Why should I own a hand mortar?
Son, a hand mortar is good for a lot of things. Vanquishing your enemies. Taking care of that damn cuckoo. Making your suicide look like an accident. Light yardwork.
But most of all: the cool factor.