Ollie Talks Airsoft goes over the Hephaestus Enhanced Recoil Spring for TM AKM & AKX gas blowback rifles to check if there is enhanced performance from these gas blowback rifles. The Hephaestus Tokyo Marui AK GBB Series Enhanced Recoil Spring is a drop-in upgrade for the TM AK gas rifles that provides increased recoil for a more realistic shooting experience.