"West Coast NZ" Beach Mortar & Black-Powder Shrapnel Bombs:

My story about Henry Shrapnel and his invention brought-back happy childhood recall to Colpepper from New Zealand's "Wild West Coast" - where to this day the bitey female sand-flies grow to the size of Jumbo-jets and the beer flows freely from the faucet of every "Cocky" or Coal-Worker's kitchen .. while the rain drums cozily on the tin roof and roasting trays of mutton chops sizzle in the oven of a coal-fired range.

Greetings Mister K,

A fascinating and informative article which brought back memories of many years past. 

DON'T TRY THIS AT HOME.
Back then, a young and very talented friend built his own mortar which we used on numerous occasions. From memory this relatively small mortar had a bore of at least 50 millimeters and the barrel length was perhaps 300 millimetres. The mortar tube was mounted on a heavy wooden base and was adjustable for elevation. Barrel thickness was around 15 millimeters.

Black powder was employed to fire heavy blunt (wadcutter style) solid steel projectiles, on the front of which was a welded steel ring to which a length of ribbon was attached to make it easier to see the projectile in flight.

The whole project worked exceedingly well, although owing to the cost of each projectile we never managed to work out the maximum range or (thankfully) the "do not exceed" propellant charge.

When firing the mortar on a deserted beach one day, we found it possible to land a shell in the midst of a bunch of seagulls standing around, at maybe 200+ meters or so.

However, the culmination of these experiments was a cylindrical shrapnel shell in which a short length of fuse in the base was ignited by the main propellant charge. It was difficult and damned dangerous to get the length of base fuse correct, but it was quite spectacular to watch the projectile splash a couple of hundred metres out to sea and then witness a sizable fountain of water erupt one or two seconds later.

Whether or not we killed any fish is unknown to this day.

We never experimented with impact detonators, although it may not be too difficult. The major problem was the inability of achieving pin-point accuracy as the mortar was not then equipped with even rudimentary sights.

A projectile with three or four spring-loaded expanding angled fins in the rear portion was on the "drawing board" at one stage but whether or not this came to fruition is unknown. The idea was to give the projectile an amount of spin in hopes of more consistant accuracy when sights were finally fitted.
Regards,

Colpepper A.