A methodology for the assessment of weapons performance/efficiency has been derived on commission from the Swedish Armed Forces. The methodology can be used to quickly and uniformly be able to assist the Swedish Armed Forces (and e.g. FMV) with data for decision-making. This methodology suggests work procedures for how one can assess the performance of different types of weapons. This report gives examples of performed work on assessments of weapons performance which is summarised into a suggested work methodology. By constructing the methodology on performed assessments its usability is confirmed. Three pieces of work were chosen as examples; the first on GBU12, the second on GBU12, GBU39 and GBU49 and the third on battalion artillery. In all three the re-use of input files is essential and the first two also shows that it is possible to re-use output files as well (burst point files). Chapter 4, were the proposed methodology is presented, is the most central part of the report. The methodology can be applied both on known weapons, were partly or complete descriptions are available, and also on newer, less known weapons, which lack descriptions at the beginning of the work process. The examples founding this methodology are performed with the simulation tool AVAL (Assessment of Vulnerability And Lethality), but it should also be able to be used regardless the tool.