Haven't seen it posted here yet even though it's pretty known by now.
Click on the "One is None" talent (gives you a 50% chance to not consume the bullet when you headshot), and just spam space bar (equip it, deequip it, equip it etc) and do that for a while, this will make the talent stack up to infinite, so after you have done it for 1-2 mins you should pretty much get your full magazine back just by getting headshot with 1 bullet.
It helps to have some lag, so if you got too good ping, download NetLimiter 4 and make your game a bit laggy.
Click on the "One is None" talent (gives you a 50% chance to not consume the bullet when you headshot), and just spam space bar (equip it, deequip it, equip it etc) and do that for a while, this will make the talent stack up to infinite, so after you have done it for 1-2 mins you should pretty much get your full magazine back just by getting headshot with 1 bullet.
It helps to have some lag, so if you got too good ping, download NetLimiter 4 and make your game a bit laggy.