>Now I have a pneumatic brad gun,
>but haven't tried it yet.  Anyone have experience with brad guns on grooved
>bottom bars?


I also use a pneumatic brad gun with 1 1/4" brads for both top and bottom
bars, two in each joint (8 nails per frame) with glue (titebond 2).  Have had
almost no splitting in pine,  a bit more in popular and oak, etc.   Typically
it's not enough splitting to require replacing the bottom bar (considering
it's glued as well)  I normally make my own frames, and use whatever
scrap wood I have in the shop. I use plastic foundation, grooved bottom
bars, and top bars.  I simply assemble them with the foundation in place
(no wedge on the top bar).

-Tim