has anyone made or have plans on how to make a brass catcher for an ar15?  Links and pics would be great.

thanks
lojack

Make a box out of wood, well, make it rectangular with half of one side open for brass to go in. You can just stand it next to the ejection port on a shooting stand.
If ya wanna make it lighter, and see through, I'd suggest making a wooden frame and nailing/stapling screen/mesh around it, also with that half of one of the long sides cut out.

A crude option:
Another option, is get a tub/bucket, string, a needle, two yards length of material(cloth, thin, just not something like silk that the brass could burn through), and a couple of rubber bands.
Cut out a 6 inch x 5 or 6 foot long piece of said cloth. Roll it, and sow it up to make a tube. Use the rubberbands to pin it to the rifle so an opening covers the ejection port, and let the other end be in the bucket.

First would be for bench and prone, second for standing or sitting/kneeling.