Dude, you know waaaaaaay too much about finish/brad nails.

Joe



not quite. really, a brad is just a small nail. a finish nail is just
a nail designed to have the head driven below the surface. a 16 penny
finish nail isn't a brad, and a large headed upholstery brad isn't a
finish nail, but the brads in your nail gun are definitely finish
nails.

the pneumatic ones are squareish as a side effect of manufacture.
they're coated with a vinyl substance that at room temperature is a
glue and under heat or pressure becomes a lubricant. this stuff is
part of why they are so difficult to pull out without breaking off and
is also used to hold the brads together before you use them. the
process starts with wire coated with this glue/lube which is bundled
together flat and stomped to generate the pressure/heat to glue them
together just enough to make the collated sticks. the heads are then
stomped from the end.

so the cross section isn't quite square. two sides are flat and
parallel, the other two are rounded.





If tht were the case then you
could theoretically have a 15ga or larger brad nailer that shot
rectangular
fasteners or a 20ga finish nailer that shot round nails.

Matt