An impact energy suppression assembly for an inert ammunition cartridge is disclosed wherein the assembly includes a barrel, a piston and a compression resistant device. The barrel has a bottom wall with an opening, at least one generally cylindrical integral sidewall, and an open upper end, and the piston has a head and push rod which extends outwardly from the piston head for connection with the compression resistant device. The piston and compression resistant device are inserted into the assembly barrel which is inserted into the hollow cavity of inert firearm ammunition for use as a training device.