Since I haven't seen any instructions on how to make one , despite seeing pictures of similar ones. I figured I would do a short Instructable on how I made mine. Sorry I didn't take any pictures along the way but hopefully I should be able to explain it without confusing anyone.
(2) 10 foot 2x4's ( wood type is unimportant)
(1) box of 2 1/2 or 3" screws
Padding for the top of the pell
rope, twine ,or duct tape to keep padding from coming undone
#2 phillips drill bit
(optional) 1/8" drill bit for screw pilot holes
Cut 2 lengths of 2 foot pieces from both 2x4's . these will form the base
you should end up with 6 pieces all together (2) 6 footers and (4) 2 footers
place the (2) 6 foot pieces side by side so that it forms a 4x4 post and screw them together
you can at this time place one end or the middle of your padding between the two pices to secure it if it's long enough
place a 2 foot piece so that it forms a capital letter L with the post and screw it to the 4x4 center post ( the blue screws)
the white screws are connecting the 2 foot pieces to each other
repeat step # 3 for all sides of the post. as you turn the post you can screw the new side to the previous side (as demonstrated by the white screws)
you should end up with what is pictured or a mirror image of it.
place it on the ground and wrap the top with the padding using the rope twine or duct tape to keep it from unraveling.
Enjoy. If yours ends up rocking like mine does, don't worry about it. As it ads to your target which ( at least to me) is good since most people don't stand still once they get hit.