The slower the reload, the easier it is to perform a fast reload. The weapon with the longest reload time - and thus the largest window for a fast reload - is the Grenade Launcher. Pick it while playing as one of the two Officers, neither of which have a Reload Speed Bonus, to maximize your chances.
Adrenaline will drastically slow down the reloading process, forcing even the quickest weapon reloads down to a crawl. Use it to achieve multiple quick reloads.