RE: Block 4x4?
Something I learned that works really really well with both field points and broadheads, also very economical... Go buy a few cans of "tuff stuff", which is that yellow insulation. Get a card board box and fill it up with the tuff stuff.. Be sure to tape the box really good so it will not bust out of the box when it expandes... Let it harden then remove the cardboard box... You will have yourself a strong durable target that will last several seasons...