Larry
Try simply putting a piece of cardboard behind the target.
I shoot all the time on 20# copy paper, but I use a cardboard target backer that I tape the target to. With wadcutter pellets, I punch reasonable holes in the target. When the holes become ragged, that is when you either move the target to a new position on the target backer or change target backers.
Check to see that the 150# paper can work in your printer. Some printers cannot handle paper that heavy, and you could jam or damage the printer. Usually for paper over 100# the paper has to go STRAIGHT through the printer w/o making a bend. To do that, some printers have a back door that the heavy paper can exit from.