Step 1: Acquire K&S Engineering brass rod. Micro-Mark actually carries it just as cheaply as you can get it direct from K&S in quantity.
Step 2: Using side-cutters for a flush butt end, cut to length. Line the spears up with the butt ends all in the same direction. (I stick them in a piece of foam.)
Step 3: On the anvil (yep; well, one of the anvils anyway), flatten the business end. One blow to each side will do the job and even the two sides.
Step 4: Shape with a Dremel, using a grinding wheel bit. I use four strokes, one down each side of each edge. This actually gives it sharp edges as well as a point.
Step 5: Optional. Spin the spear lightly against the edge of the grinding wheel to give the effect of a socket on the spearhead; or spin the butt end to create a point or spike, as on a hoplite spear. Sometimes I run the butt end across the wheel just to make sure it's flat.
If you do a bunch at a time in an assembly-line operation, it only takes a few seconds per spear.
Wise men tell me the same thing can be done with the harder sort of florist's wire, and that you can squash the head in a pair of pliers, and that the wire will not turn into limp spaghetti in use. As I have only ever seen the softer, more pliable type, I have no experience of this.
There are also those who use plastic rod, which is also more easily formed, but wich is prone to breakage in handling. I want my figures inflicting damage on the clumsy and ham-handed, not suffering it from them!
Allen