Cinder Blocks, used concrete (Newport News, Bruton Ave)

Looking for 4 or 5 old used concrete cinder blocks to practice driving nails into them with a Powder Actuated hammer, using 22 caliber blanks. Concrete remaining on used blocks from demoed building is OK. Practiced today but only found solid concrete bricks to drive nails into. Hopefully cinder blocks are softer and won't crack and shatter so bad.