We see it go around that you shouldn't do the following things:
Have safeties removed from a gun or have "other" modifications done to firearms that we plan on using for self defense. We shouldn't use reloaded ammunition or "hand loads" and we "Should use the ammunition that your local Police uses."
So where did all this come from? Almost all information regarding lawyers and defensive use of a firearm can be traced to Massad Ayoob.
Regarding the modification of a gun:
I did not remove the internal lock, for the simple reason that I’ve seen a prosecutor raise hell about a deactivated safety device when trying to establish the element of recklessness that is a key ingredient in a manslaughter conviction. “Ladies and gentlemen of the jury, the defendant was so reckless that he DEACTIVATED A SAFETY DEVICE ON A LETHAL WEAPON, and so arrogant that he thought he knew more about the gun than the factory that made it!” That’s a mountain I’d rather not have to climb in court, nor debate in front of twelve jurors selected in part by opposing counsel for their lack of knowledge of firearms.
Ayoob on using hand loads:
This was the first case where I saw the argument, “Why wasn’t regular ammunition deadly enough for you,” used by opposing counsel. They charged Kennedy with aggravated assault. They made a large issue out of his use of handloads, suggesting that they were indicative of a reckless man obsessed with causing maximum damage.
The following information comes from the same URL above
This is the classic case of gunshot residue (GSR) evidence being complicated by the use of handloaded ammunition, resulting in a case being misinterpreted in a tragic and unjust way. On the night of 2/26/89, Danny Bias entered the master bedroom of his home to find his wife Lise holding the family home defense revolver, a 6” S&W 686, to her head. He told police that knowing that she had a history of suicidal ideation, he attempted to grab the gun, which discharged, killing her. The gun was loaded with four handloaded lead SWC cartridges headstamped Federal .38 Special +P.
Autopsy showed no GSR. The medical examiner determined that Lise Bias had a reach of 30”, and the NJSP Crime Lab in Trenton determined that the gun in question would deposit GSR to a distance of 50” or more with either factory Federal 158 grain SWC +P .38 Special, or handloads taken from his home under warrant for testing after Danny told them about the reloads. However, the reloads that were taken and tested had Remington-Peters headstamps on the casings and were obviously not from the same batch.
Danny had loaded 50 rounds into the Federal cases of 2.3, 2.6, and 2.9 grains of Bullseye, with Winchester primers, under an unusually light 115 grain SWC that he had cast himself, seeking a very light load that his recoil sensitive wife could handle. The gun had been loaded at random from that box of 50 and there was no way of knowing which of the three recipes was in the chamber from which the fatal bullet was launched.
The decedent attacked Robert Barnes and his young daughter with a large knife and was shot to death by the defendant with SJHP .38 Special reloads from a Smith & Wesson Model 36. The distance between the two at the time of the shooting became a key element in the trial, and a misunderstanding of that distance was a primary reason he was charged with Murder. The evidence was messed up in a number of ways in this case, and I do not believe the reloaded ammo (which the prosecution did not recognize to be such until during the trial) was the key problem, but it definitely was part of a problem in reconstructing the case. We were able to do that without GSR evidence, and Mr. Barnes won an acquittal. In this case, I believe the use of factory ammo, combined with proper handling and preserving of the evidence by the initial investigators, would have made the defense much easier and might well have prevented the case from ever being lodged against him.
Things on "the net" are often subject to the same phenomenon of the kids game "Telephone" and get distorted time after time. The argument regarding modifications to carry guns is mainly aimed at lightened trigger pulls and the removal of a safety device. It has morphed into a superstition that if you replace the sights, add a different set of grips etc that you will be prosecuted to the max for having a customized tool of death and destruction. If you want to look at the light trigger issue, search for incidents of where negligent discharges from police have killed compliant suspects. Under stress it is not uncommon for the trigger finger to move to the trigger. If startled or just careless, you can get a very loud, unexpected bang.
This was the type of stuff that caused the removal of the single action capability of revolvers for some departments and is the reason for the New York Trigger for Glocks. Also of note is cases where suspects have claimed that the cocking of a revolver was used to intimidate them...but that's topic for another time.
It is thought that having too light a trigger is a bad things as it can be used against you that you didn't intend to shoot someone and had a negligent discharge resulting in the death of some dirtbag. Don't believe me? That's paraphrased from The Gun Digest Book of Combat Handgunnery 6th Edition by....you guessed it, Massad Ayoob.
Now regarding using the ammunition that your local law enforcement agency uses. This is primarily a result of of the Harrold Fish incident , Mr. Fish carried a 10mm which is considered to be at the top of the power spectrum, and while there were other issues with the incident which resulted in his conviction, the prosecutor did in fact make issue of the DEADLY 10mm JHPs that Mr. Fish used that is more deadly than what the Police themselves use.
Using what your local police use is thought to be a defense against such claims that you are using "Killer ammunition". I don't buy into this OTHER THAN that Police Officers generally use top notch premium ammunition that has a good track record at "stopping threats" Given certain circumstances the 10mm might be a viable option for some.
So while some of "Don't modify your gun, don't use handloads, and use what your police use" can be dispelled as "BS" Some of it isn't. Does this mean that you HAVE to use the exact same ammunition that your Police use? No but if you don't know jack about what's good and bad ammunition, it's a good place to start. Can you use relaoded ammunition? Sure. But really, what's the benefit? Some people I've seen ask about that detail don't even reload. There are benefits to using factory ammunition and by NOT using reloads, guess what, it's now a non-issue that you don't have to worry about and one less thing to worry about after shooting someone sounds good to me. Does this mean that you can't replace the grips on your gun with something more comfortable? NO, but it does mean that you probably shouldn't engrave "Kill them all let God sort them out" on the side of your gun or the ever fabled "Punisher Grips" on your carry gun...I admit it, I really do want pair, but I wouldn't want to be the one to use that gun in a shooting incident. Does this mean that you shouldn't remove a safety device? I'll leave that what open for debate, but I am of the opinion that no good would come from it.
The bottom line is this, be sensible in your choices. Look at things from multiple perspectives and make informed decisions. Don't believe everything you read on the internet, but when the real experts like Massad Ayoob speak, it's wise to listen.