Go to www.fisasrange.com/photos.html you can see the stands I had made for barricade positions.
They are exactly like the standard re-bar target stands only these are built to hold a 2x6 in the center. The rocks at the base were used to keep the target from rocking in my more primitive days. Now I use 2 bags of tube sand to make the post stable enough to lean into it. They are perfectly portable, compatible with all the 50 yard positions and I have a local machinist who only charges $30 to make one.