I've been using QuickLOAD for many years and found it has a wealth of information. Here's the caveat: WARNING: QuickLOAD is a computer simulation of centerfire cartridge performance. YOU MUST NEVER just “plug in the numbers” and use QuickLOAD’s output for a load recipe. That is foolish and dangerous. There are many reasons why the data QuickLOAD generates may not be safe in YOUR gun.
That said, it's fantastic for doing "what if's" with established loads from a reloading manual …. like changing bullet seating depth to see what happens to chamber pressure or using a different style bullet with the same weight as another bullet. Mostly I use it for estimating chamber pressure to match with lead bullet hardness and find it is very close when you adjust the factors. As an example, QuickLOAD assumes an unvented pistol or rifle barrel …. not a revolver barrel so you have to make adjustments for actual bullet travel and the B/C gap. I found each .001" of B/C gap accounts for a loss of 1.5% of the muzzle velocity.
A revolver has a true barrel length plus about 1/2" extra bullet travel in the cylinder throat. So a revolver with a 6" barrel actually has about 6 1/2" of bullet travel whereas a pistol with a 6" barrel will have about 5" because the cartridge takes up some space. Once you make these adjustments, velocity will track pretty close with most powders. QuickLOAD assumes a standard primer so if you use magnum primers, likely the stats will be a bit low.
Some of the handy features are ….there are 1500 cartridges, more than 270 powders and 2500 bullets listed, each with SAAMI, and/or CIP pressure standards. Wildcats are also listed but don't have established SAAMI specs. You can design your own bullet if you want. Yes, there are a few powders missing so I can see dissatisfaction if a powder you use is not listed, however every powder I use is listed so I'm a happy camper. It is an expensive program but it also includes "Quick TARGET", which is a powerful program that predicts downrange external ballistics statistics.