These three cvars affect guns while incapacitated. Did some research with sophia to see what effect they have on pistols and magnums.
survivor_incapacitated_accuracy_penalty : 0.4 : , "sv", "cheat", "rep" : Penalty given for shooting while incapacitated. survivor_incapacitated_cycle_time : 0.3 : , "sv", "cheat", "rep" : New cycle time (RoF) used when incapacitated, overriding weapon. survivor_incapacitated_reload_multiplier : 1.25 : , "sv", "cheat", "rep" : Multiplier to reload time when incapacitated.
---- RELOAD TIME ----
This one is easy. All weapons are affected by the reload multiplier, and they all take longer. Since it's a multiplier, it affects the base gun stats.
---- CYCLE TIME ----
survivor_incapacitated_cycle_time (aka the fire rate) is an override, so it will be 0.3 for every weapon, whether you have one pistol, two pistols, or a magnum. This is the amount of time in seconds between shots. Yes, you read that right - two pistols do not fire any faster than one pistol, and which all have the same fire rate as the magnum.
To make things more interesting, the magnum already has a "standing" cycle time of 0.3. So the magnum shoots at the same speed whether you are up or down - in other words, there is no fire rate penalty for the magnum. However, the magnum is in fact affected by this setting, and if you increase it to 0.1, all guns shoot much faster.
Meanwhile, the cycle time of a single pistol is 0.175 while up and 0.3 while down - pistols fire about 71% slower while incapped when you have just one pistol.
The cycle time of two pistols (the game scripts do not contain a separate cycle time for dual wielding; I'm assuming that they are each individually limited to 0.175, which is consistent with the left4dead wikia) would then be 0.0875, meaning dual wielding is 243% slower when you go down.
---- ACCURACY ----
This is truly fascinating. The magnum is COMPLETELY unaffected by the accuracy penalty while down. Penalty values from 1 to -1 were used (with -1 being pinpoint accuracy). The pistols had a dramatic and immediate response, while the magnum maintained its normal accuracy regardless.
---- CONCLUSION ----
The reload penalty affects all weapons equally. The fire rate penalty affects all weapons, but not equally; the penalty has no effect on the magnum, and double the effect on the double pistols. The accuracy penalty does not even affect the magnum.
And it's also hilarious to set the reload penalty to 0.1 and the accuracy to -1 and the fire rate to 0.1. Going down makes you a formidable opponent!