dawei, Only release sites are restricted to steel. ( and only starting this year in eastern washington)- of course duck and geese hunting is federally regulated. Most of the free world is not a release site. In other states they do not have release sites. I started hunting in Montana before moving here. I do hunt the release sites for gas savings. If you are willing to drive east there are other places to hunt. Just picked up 4 boxes of Prairie Storm #6. The hunting has really changed in the last ten years with farming practices and lease hunitng etc. I just love to get out where my dogs can do some real work.