Here's my experience and opinion re: handloads:
Rifle: You can develop handloads that are as reliable, and more accurate than factory ammo. A rifle can be fine tuned for best accuracy and performance with a variety of bullets and powders available.
Shotgun: You can hanload for target or hunting. Did it for years. Don't know when I last killed a bird with factory ammo, except for waterfowl that require steel shot. You can handload that, also, but I never set up for it.
Pistol: If you're a very good handloader, it MAY be possible to equal the reliability of factory ammo, but I don't know if it's possible to exceed it. Even if you have access to the bullets used in the best factory ammo. Yes, you may find a bullet that's more accurate, but is it the best for SD?
I'm an experienced handloader, and I don't carry handloads for SD. It's already been pointed out that many handloaders think more highly of the quality of their loads than the facts would support.
The legal points have been discussed.