1911 mainspring?

[Lycanthrope]

22-24lb is pretty stiff and will light even high primers (I believe 22 is factory). I've run 19lbs for years to reduce trigger pull and they light everything except high CCI primers. 17lbs will occasionally fail to light CCI , but will light Federals.

Remember, that the mainspring will soak up some of your slide inertia and going too heavy can cause failure to extract with lighter loads.