Quickswitch

Quickswitch refers to increasing firerate and elimination of shooting speed penalty by switching in certain pattern.

One weapon
After firing a weapon, switch to any other (to to melee, or throwables), then back. Result would be your survivr still holding same weapon but being able to move at full speed.

For weapons such as Mosin-Nagant, SV-98 and AWM-S quickswitch is essential to be competitive; it both increases both firerate and eliminates speed penalty.

For Spas-12 or M870 effect on firerate is almost zero so it

For weapons such as Saiga-12, Model 94, USAS, Super 90 quickswitch would decrease firerate; user would have to choose between getting max DPS or eliminating speed penatly.

Two weapon combo
First weapon fired, switched to second, second fired, switched back to first, 1 second cooldown.

Double pump nerf
Since version 0.6.0 (sep. 7, 2018), switching from pump shotgun (m870, spas-12) to another pump shotgun triggers switch cooldown; no more possible to fire two in quick succession. The only effect left is elimination of speed penalty.