For many years, the benchmark for indicating perforation performance in the well was a surface gun test into concrete. However, it became recognized that shooting an API concrete target at a surface could not be effectively correlated with actual downhole conditions of overburden, reservoir pressure and rock properties. After many years of effort on behalf of the Operators, the service contractors and manufacturers were finally persuaded to accept that the correlating of real well conditions with concrete was not helpful to the Operators and their well performance. Since then, new standards have been written to promote shots into stressed rock targets as the standard for identifying performance down hole. All the contractors and manufacturers now have dedicated facilities to provide stressed rock tests and are actively developing improved charges that work well in real reservoir conditions, rather than concrete at surface. Having passed through over a decade with almost no new developments in perforating, the last 5 years have seen significant developments in  technology, with contractors and manufacturers working actively to improve performance and technology.