I've never understood how using handloaded ammo in your EDC would be an issue when and if you had to defend yourself. How do you make a handloaded round more lethal than factory +P, or +p+ ammo without damaging yourself or destroying a firearm? I guess there could be some wild assertion that you put poison in the tip of a HP or used nuclear waste instead of lead in the bullet makeup.
As long as a load you were using could be pointed out in one or more published lists of handload data, I think any accusaton would quickly fall flat.
As far as asserting that modifying a gun to make it more lethal goes; I mean, come on, what you possibly do to accomplish that? Of course you could cut off the barrel of a shotgun or rifle, or turn a semi-auto into a full auto. Either would be illegal and, I guess might fall into this category.
I can't imagine that by changing your grips to fancy ones on your 1911, adding night sights, or a laser would apply though.
I've seen this topic come up from time to time in this and other forums, but no one(that I'm aware of) has ever been able to point to a single documented case where this impacted the outcome of a trial.