Tiny (1 to 3mm diameter) needle-like rockets with steel tips. The rockets were ... any misalignment of the nozzle holes would cause the bullet to fly poorly. Bertha – from An Introduction ...

There are three tool options to consider when drilling large-diameter holes in thick steel: twist drill bits, hole saws and annular cutters. 1. Twist drill bits. Especially in steel thicker than ...

But Andre Horne has been looking at something a little older - 184-year-old bullet holes. The firearm expert has been tasked with investigating these holes in stone pillars at Newport's historic ...