From what I have read they were only 2/3 of an ounce. One test showed a projectile could penetrate 24 inches of packed sand, the same as a 50 caliber bullet fired vertically. The big benefit is that any aircraft can deploy them by simply dropping them from the back of the plane. They can be kept in an open crate, no need for a deployment system.
I wonder what it would have been like if, rather than bombs, the B-17’s and B-24’s had simply dropped tons and tons of these things. Talk about “carpet” bombing. It would bring it to a whole new level. Only underground stuff would be spared, or lower floors of multi story buildings. Maybe the last planes in the raids could have the actual bombs.