and firing of the next round automatically to proceed in a normal fashion in the preferred embodiment there are three slideable weights 23 of identical size and weight made of steel and three slideable washers 24 of identical size and weight made of low friction plastic a satisfactory distance u201c x u201d with this combination of weights and washers has been found to be approximately u215b inch the number of weights and washers and what they are made of can be any number and any material the inclusion of slideable washers 24 is optional they provide further cushion if made of cushioning material the numbers sizes and materials selected for the weights and washers in the preferred embodiment were based on convenience and cost of production this design has been tested many times in fn herstal fnc rifles converted to fire low energy training ammunition to demonstrate the elimination of training bolt carrier assembly bounce off the base of training case 27 with complete success the invention while demonstrated by the fn herstal fnc assault rifle is applicable to all blow back firearms wherein bouncing of the bolt carrier assembly or equivalent assembly off the base of the cartridge case or breech may cause a misfire fig8 a and 8b show respectively a disassembled and.