A VERY IMPORTANT POINT IS THAT THEY ARE CRS, OR COLD ROLLED STEEL!!! NOT HRS!!!

Home Depot and Lowes confuse everybody unfortunately. For some stupid reason Home Depot sells CRS but labels it "Hot Rolled". I do know that Tractor Supply sells true HRS, and you can get true HRS from McMaster-Carr or Fastenal too. True HRS has a dirty looking scale over it and when you bend it, it tends to "pop" into the kink and the kink is very easy. CRS is a smooth bar with no dirty scale, just usually covered in oil and doesn't "pop" into the kink. It's an extremely important distinction to make.

Here are two links, the first one shows a 3/8x7 true HRS bar.

http://www.gripboard.com/uploads/1206139302/gallery_14062_890_31252.jpg

The second picture shows a CRS bar.

http://www.gripboard.com/uploads/1144516925/gallery_4711_483_134141.jpg

Schapm has the correct dimensions except that, as Jeff pointed out, the RED nail is 5/16x7" CRS