TOW's staking tool moves too much metal all at once. It requires much too ;heavy a blow to do this, and you will likely dimple your bore.
I use a nail set with a flattened end a little over 1/16" in diameter. I ground a shallow groove alone one edge so I can get it closer to the staple while stamping in the barrel steel. I start with a blow on each end, then two on the sides, and then another to make up five strikes on each leg of the staple. It makes for a neat job and it is impossible to remove a staple set in like this.