For a model 1911;
place index finger on magazine release, press to dump mag, if it hangs up or even if it doesnt...
place pistol under right arm pit (pull mag if necessary).
reach to spare magazine with left hand insert into pistol,
grasp pistol, release slide, take aim...
Not at all difficult... but slower than reloading with 2 hands.
Wheel guns are much more difficult... especially with the twist to releast style of speedloader.
As always practise makes perfect.
Enjoy!