Hey 10,
When you ask about "defensive" ammunition, the term "defensive" takes in a lot of territory and consideration.
For example, if you are talking about wanting to inflict as much tissue damage as possible on some dangerous animal (human or otherwise) that has a thin skin, then you would probably want to use a bullet designed for expansion such as a hollow point. A shotgun could also be a good choice here. However, if you are put in danger by someone wearing body armor or by a large animal with a thick hide, then you would probably want to consider a fully jacketed bullet. A hard cast big bore bullet such as a 45-70 can be very effective on big animals where deep penetration is desired.
The big difference between pistols and rifles is also significant. A great big 44 Mag is very poweful compared to other pistols, but its power is small when compared to an ordinary 30-30 rifle. Like the old saying, "Never take a knife to a gun fight.", you really would not want to go up against a rifle with a pistol.
Having said all that, let me back up a few steps. I am not suggesting that you should always be carrying a pistol, rifle, and a shotgun with you. You really need to evaluate your risk and be prepared accordingly.
As far as defending your use of your own ammunition in court, I wouldn't worry too much about that. If you have to go to court because of a shooting incident, the ammunition you use will not be a significant factor in the overall scheme of things.
And if you choose to not use your own ammunition because you have "too many misfires, goof ups, etc.", then you really should not be reloading any ammunition. If you cannot reload ammunition that is not only reliable, but also better than factory ammunition, then you are wasting your time. Reloading quality ammunition is not about making cheaper bullets as fast as possible. Reloading is a craft, and, if you practice that craft, you can build better ammunition than you can get off the shelf at the local gun store. Misfires? If you have any misfire, something is wrong with your process. The first box of ammunition I loaded was with a really slow Lee Loader, but I have never had a misfire in nearly forty years of reloading.
By all means, use your own ammunition for whatever "defensive" purposes you may have. You may have "defensive" ammunition in pistol, rifle, or shotgun. In any case, make it well and use it well.
Best wishes,
Dave Wile