I can try and duplicate those factory loads for defensive purposes, but I just feel like I'd be flying blind unless I tested the terminal performance of my own loads as extensively as ones from the factory.
Do you own a Chronograph? If you do, this problem is rather intuitively
solved.
If you use a recognized bullet (eg, something like a Speer GDHP) and load it to the correct velocities, it'll do the same "job" a factory load will. All you need is a box of the desired bullets and a chronograph. The component bullets the major factories sell are exactly the same as what they use in their commercial ammo- loading them to similar velocities as their recipe will yield similar results.
For example, I like the Speer GDHP 230 gr .45 ACP load. I could replicate the performance of that load by buying a bunch of .45 cal 230 gr GDHP component bullets, load it up to about 800-900 fps or so and I'd be in the performance window of that bullet, just like the factory. (somewhere in the "bible" I have chrono data for factory defense ammo I like to use..... so getting in the same speed range wouldn't be hard. ) No need to do ballistic testing because Speer, Remington, or whoever, has already done it for me. (and this has been usually backed up by other sources, as well. )
One thing that does suck is there are a limited amount of component bullets out there suitable for self defense (IMHO) and they are sometimes hard to get. Speer, Remington, and Barnes are pretty much it for pistol calibers... and the bullets Barnes sells are more centered around hunting ammo.
All this aside I don't do it..... I like sealed primers and flash retardants... and I have a fair amount of defense ammo in most calibers I would ever hope to use, but if I had to load ammo I could trust my life to, I have no doubt I could do it, no problem, without hesitation.
-Mike