I wouldn't use a regular arrow as the arrow shaft (think thinner walls) "may" not take the abuse of the shot. If the arrow shaft flexs and shatters, it could be a bad day for all involved.
I've used an old bolt with a blunt tip, and usually use the Carbon Express decocking bolt.
The old bolt can be a pain if the ground is soft or rocky, they can sink in pretty deep, and don't last through too many firings.
The Carbon Express bolt with the steel flat tip is pretty good, but the nock can blow out if you hard ground or a rock.
Last edited by AH64guy; 07/29/15.