The downside to fragmenting specialty loads like the Glaser Safety Slug is limited penetration. The upside is massive tissue destruction. This is easy to see by looking at the gelatin block. The Glaser Silver Safety Slug is a copper-jacketed bullet filled with No. 6 shot. The bullet is capped off with a silver-colored plastic ball. When the bullet begins to penetrate, this plastic ball is driven back into the bullet causing it to erupt, distributing the No. 6 shot into a wide pattern inside the gelatin. Two advantages of the Glaser Slug are minimization of over-penetration and ricochet. An 80-grain BLUE version filled with No. 12 shot is also available.