Somewhat recently a patch released what SD terms “Reload cancels reload”, which is effectively another way of cancelling reload by pressing “R”. After trying it for a bit I noticed that while it is certainly faster than weapon switching to cancel reload, it is still slower than sprint to cancel by about ~0.2 seconds (Tested using M4A1). While not incredibly significant, a 0.2 second increase in reload time is definitely noticeable. The reason for this delay is that sprint cancelling is effectively instantaneous - the moment your clip refills, sprint cancelling allows you to immediately begin shooting. With the new option, there is a raise/lower animation added, which introduces this 0.2 second delay.
This results in a noticeable trade-off for the perk double time. Do you want a 0.2s faster reload, or would you prefer the ability to sprint at the cost of slower reload (cancelling)? Changing the mechanic to instant shooting after clip refill will make double-time loadouts more viable. We really shouldn’t be seeing players deliberately choosing iron loadout cards to avoid this perk.