The highly demand of delaying systems in both civilian as space industry and military as fuses forces the researcher to initiate different research interested area. The common compositions for gasless delay compositions was tungsten (W) fuel modified polyvinyl acetate (PVA), BaCrO₄, KClO₄. The compositions are fabricated and loaded in delay containers. This research demonstrated the effect of varying the fuels (W) using both theoretical and experimental methods. Using the ICT code to predict the performance of the compositions and using the central testing unit for burning measurements. As the fuel percentage increase from (25% to 45%) decreasing in both oxygen and heat of formation is the main theoretical result for increasing fuel percentage. The decay of burning rate as the percentage of fuel increase have also been measured. Different characterization test like sensitivity tests and thermal analysis also have been done. all results revealed that compositions are very safe and reliable during manufacturing and usage.