On Dec 29, 12:00 pm, dpb wrote:
....
I have to admit I've don't recall ever seeing "L" or "T" in a
pneumatic nail ...

OK, I did look them up--they're for extra holding power w/ the
increased head area. Definitely _not_ what you want for finish work,
particularly if you're planning on not painting over it. They would
leave as messy/large a hole to fill as a staple when finishing.

I've never personally felt a need for them -- for underlayment, etc.,
I'd simply use a FRH ring-shank and set pressure to leave them
slightly below surface. But, they would certainly work for the
purposes outlined by the manufacturers but definitely stick to either
brads or conventional finish nails for finish work.

--