Gun Modifications, Light Triggers and Reloaded Ammunition
This article first appeared in the Network's September 2013 journal.
by Marty Hayes, J.D.
Gun enthusiasts often challenge authoritative advice to avoid radically modifying their self-defense gun, reducing trigger pull weight or carrying it with hand-loaded ammunition for self defense. As gun lovers, as well as self-defense practitioners, many who argue these points find it difficult to separate the features of a gun that is fun to shoot from one that is difficult if not impossible to defend in court.
The Big Picture
If you are involved in a self-defense shooting, your gun will be seized as evidence early in the criminal investigation. Responding and investigating officers do not know what occurred, and until they thoroughly investigate the incident they will not know that you fired in self defense. In a perfect world, all the evidence relating to the shooting is collected for later scrutiny, evaluation, testing, argument and use in court. Your gun will be a major piece of evidence at trial. Before trial, it will be checked for fingerprints, photographed, tested for DNA evidence, and possibly fired during gunshot residue and stippling testing. It will be inspected by firearms experts from the state crime lab, to make sure that the gun functions, that all the safeties work, and the trigger pull weight tested to see if it meets factory specifications. Any anomalies, some caused by modifications, will be noted in the crime lab report. If we were writing a movie script, the gun would have its own role, and if the movie was good enough, the gun itself might win a “best supporting actor” award.
The ammunition fired will play a supporting role, too, but since the average person does not understand the field of ballistics as well as they do guns, the ammunition used is often, although not always, glossed over. I do remember testifying in a case in which the ammunition played a huge role in the trial, when my testimony explained the nuances of .38 Special v. .357 Magnum, hollow point v. round nose and wad cutter bullet design. Ammunition also plays a major role if the distance between the muzzle and the wound is an issue, as it often is.
When distances are contested, both the prosecution and the defense will likely conduct gunshot residue and stippling testing, trying to determine how far the muzzle was from the inflicted wound. This was recently illustrated in the George Zimmerman prosecution.
Pre-trial legal procedures play a big role leading up to trial or dismissal of charges. Whether or not you are prosecuted for murder or manslaughter or whether your shooting is deemed justifiable by reason of self defense, can hinge on the prosecution’s opinion of whether or not firearms or ammunition issues could lead a jury to convict or acquit. I would like to think that most prosecuting attorneys do in fact want to see justice served, and if a person is innocent of a crime, they should chose not to prosecute. The sad reality, though, is that many people are prosecuted despite overwhelming evidence of justifiability, as was George Zimmerman.
Many prosecutors have a good understanding of issues relating to self defense. In deciding to pursue a case, they must weigh whether or not they can argue convincingly that you were somehow negligent or reckless based on the type of gun you used or what you had done to your gun prior to the shooting. The prosecutor knows the jury pool and knows if a jury can be swayed by their spurious arguments and accusations of negligence, recklessness or just plain maliciousness.
The Jury Weighs the Evidence
Your guilt or innocence will be determined in court by the evidence presented, which is weighed by the experiences, knowledge and education of the members of the jury. Do not expect jurors to possess the same level of knowledge as you do about self defense. If you live in a gun-friendly community, the jury should include gun owners, as well as non-gun owners. Your jury will usually contain a mix of people who have all been “trained” by TV and the movies, who are likely not NRA members, and who may or may not already have a bias against guns and armed self defense.
Because the prosecution and defense have pre-emptory challenges during jury selection, at least you should not have rabid anti-gunners on your jury, nor will you have people who have used a gun in self defense or are admittedly pro-gun. You are not guaranteed a jury of your peers, just a jury of fellow citizens.
These jurors have to judge both the prosecution’s accusations and the defense’s explanations about modifications, light triggers and reloaded ammunition used during a self-defense shooting in order to reach a verdict of guilty or not guilty. Let us next study those issues in detail.
When a forensic firearms examiner for the state examines a gun used in a shooting, any external modifications made to the gun are listed on the crime lab report given to the prosecutor. If the prosecutor believes that any of these modifications may paint you, the defendant, in a bad light, these findings will be heralded in court. The prosecutor asks the forensic firearms examiner to explain during testimony what they found when they examined the gun, and then asks the examiner to compare your gun to an unaltered, factory stock gun. If you installed different sights, an extended magazine release, an extended slide lock/release, or cut the frame down so you could conceal the gun easier, that will be discussed.
The prosecutor will then ask the purpose of these modifications. If your defense attorney is savvy, he or she will object at this point, because your purpose is outside the knowledge of that witness. Only the defendant can testify why he or she made those modifications. An argument will ensue between attorneys with the judge as referee. If the judge is sympathetic to the prosecution (most are, being former prosecutors themselves), the objection will be overruled and the examiner allowed to opine why those modifications may have been made. The questions might go something like this:
Q: Why do people put different sights on guns?
A: To make it easier to kill people.
Q: Why do people put extended magazine releases on guns?
A: Because on some guns, the factory magazine release is too small to make it easy to quickly reload the gun and continue firing.
Q: Why might a person put an extended slide release on a gun?
A: For the same purpose of an extended magazine release. If the person just got done shooting all the bullets in the magazine and he wanted to quickly get the gun reloaded to continue killing, an extended slide release will save them a whole second as opposed to racking the slide manually. A good shooter can shoot 4 or 5 more bullets in that extra second.
Now, put yourself in the place of a 65-year-old grandmother serving on a jury. She has never shot a gun in her life and sympathizes with the “gun victim” mantra as reported by the anti-gun media and perhaps she even voted for our anti-gun president and vice-president. Do you think this line of questioning might create in her mind a negative opinion about you, the defendant?
Many readers are retorting, “But, Marty, those things are easily explained!” I agree, but must now ask, “Who is going to explain them?” Are you a firearms expert who is accustomed to testifying in court? Do you know how to educate your defense team so they can effectively cross-examine the prosecution’s witness? Probably not. The good news is that if you are a member of the Armed Citizens’ Legal Defense Network, Inc. we can provide those experts to help, but even for our Network members, the best for which we can hope is to neutralize the state’s argument, but the prosecution’s smears upon your character will linger in jurors’ minds.
Up to now, we’ve discussed modifications to gun function only not appearance or style. Adorning your firearms with cutesy little illustrations can only work against you. The only visual modification I support would be to hard chrome or apply another tougher finish than the rust-prone blued finish your gun may have come with.
A carry gun should be all business, not an art project.
What’s the bottom line on gun modifications? Make them sparingly and for a specific purpose that is easily explainable. Other modifications pose such problems as to seriously jeopardize your plea of self defense.
Reduced Weight Trigger Pull
Modifications to trigger pull weight on your defensive firearm deserves detailed discussion. Earlier in the month I received the following e-mail from a Network member, Charles in South Carolina, asking–
“I’ve read all the advice against making any modifications to triggers on self-defense weapons but it seems to caution against making the trigger lighter. Does this include ‘combat action trigger’ or duty/carry modifications performed by the manufacturer? The trigger pull on a striker fired weapon remains at 4.5 pounds but the reset and slack are significantly reduced to improve accuracy (reduce user induced deviation in sight alignment through less trigger movement).”
I don’t believe modifying the trigger without reducing the trigger pull weight will create an issue, because firearms examiners will likely just measure the trigger pull weight, not the quality of the trigger. If it is lighter than factory standard, an issue may arise.
I recently spoke by phone with another Network member, Scott in Nevada, who took exception to my recommendation that a defensive firearm’s trigger pull weight be at least 5 pounds. He owns a Wilson Combat 1911 with a 3-pound trigger. He is committed to carrying that firearm on a daily basis, and trains a lot with it. After a phone conversation, he e-mailed:
“Marty’s (and the entire industry’s) standard is rapidly moving towards being archaic, or ‘old-school.’ Before too long, inevitably, ACLDN will be called by one of its members with that dreaded phone call for help, and your team will be faced with what will on the surface, appear to be an issue, or what you might consider, a problem…that being, your customer just might be a guy like myself.
“So please, consider my words carefully. Please do some research into this and I’m certain you will find that I speak the truth. Times are changing. I think the courts are way behind the curve here and that mentality would do well to reconsider. Thank you for taking time to chat with me earlier today. I enjoyed every minute of it.”
I want to respond with facts:
The weight of the trigger pull will be established by the state’s firearms examiner and included in his or her report. If the trigger pull weight is appreciably less than standard, as would be true in Scott’s case but not Charles’, the prosecutor can choose to make an issue of it just as they can with the other modifications discussed earlier. Any of these issues can feed accusations of recklessness or negligence.
Assuming that the defendant can testify that he purposely aimed the gun at the deceased and purposely pulled the trigger, the weight of the trigger should not matter without a claim of negligence, accident or inadvertent discharge of the firearm. In the real world, though, the prosecution can argue that it was negligent for you to have such a light trigger in your self-defense gun. The prosecution can forward the theory that you negligently discharged the weapon into the body of the deceased without cause to do so, and because of your negligence, you are criminally liable for his death. If the jury buys this argument, you go to prison for manslaughter.
The very same argument would then be used in a civil suit against you for negligence. The level of proof to win a negligence suit is merely a preponderance of the evidence. This single detail, two pounds difference in trigger pull weight in your self-defense firearm can tip the scales of justice ever so slightly against you. You lose the civil suit, despite the testimony of expensive expert witnesses, despite your claims of innocence. And dear Network members, even though we help you fight that unmeritorious lawsuit, we cannot help you pay the damages. That is on your shoulders alone.
When Scott and I were discussing trigger pull weight, I asked him a simple question.
“Will Bill Wilson come to court and tell the jury, on your behalf, why it is acceptable to put a 3-pound trigger in a defensive handgun?” If I carried this gun, I would want to know the answer. I thought that it was prudent to find out what custom 1911 makers believe is a responsible trigger pull weight, so I checked out some websites and called other gun smithing businesses that didn’t list trigger pull weight specifications on their websites. Wilson Combat pistols come with a 3.5 to 3.75 pound trigger pull. When I phoned Wilson Combat, I learned they would increase trigger pull weight if the customer stipulated, in other words, you can order a Wilson Combat gun with a 5-pound trigger pull.
Others sellers of custom 1911s specified–
Heirloom Precision, 4 pounds
Les Baer, 4 pounds
Nighthawk Custom, 3.75 pounds, but they will customize pull weight upwards if requested
Kimber, 4 pounds
Smith and Wesson 4 pounds
Springfield Armory 4 pounds
Para Ordnance, 4 pounds
These are the specifications of either custom gunsmiths, or the custom shops at the larger gun manufacturers. When I called to ask Colt about the topic, they refused to tell me over the phone.
Wondering what is the norm for a non-custom, stock 1911 trigger pull, I weighed some single-action semi-automatic pistol trigger pulls from my family collection.
Here are the results:
Para Ordnance, 5.25 pounds
Springfield Armory EMP, 6.5 pounds
Detonics Combat Master, 6 pounds
Colt Defender, 5.25 pounds
While, my survey of gunsmiths showed that a 4-pound trigger is the norm for a custom 1911, the stock guns will likely average over 5 pounds. This is important, because if a prosecutor argues this issue to a jury, he or she is trying to portray you as behaving recklessly or below normal standards of care. You want the jury to see you as normal, like one of them.
One of the best things about being part of the Armed Citizens’ Legal Defense Network is the ability to tap into the collective knowledge of its members, some of whom have worked for decades providing expert witness testimony on exactly these questions. Wanting this article to reach far beyond my own opinion as just one expert witness, I posted the question to several members of our advisory board.
Their thoughts on the topic follow.
At a 3-gun program here in Colorado earlier this week, a female student was with us, sporting an expensive, custom 5-inch 1911 from a well-known manufacturer, for whom I have a great deal of respect. However, the trigger, crisp and breaking-glass-like as it was, was far too light for a serious, carry pistol. It broke at 3 pounds, and I indicated to her that it was too light for a defensive pistol, in my opinion. She graciously accepted my comments, but she clearly loved her beautiful pistol!
She loved it a little less after a high-stress exercise in which she was required to transition from her rifle (which had just run out of ammunition), to her pistol, and engage a close threat. She smoothly made the transition, drew her pistol, and fired 3 rounds at the immediate threat.
The first 2 were carefully aimed and struck the target in the center, as planned and intended. The third shot was an AD (accidental discharge). The pistol was in full recoil from the second shot and it discharged while still angled upward. It startled her. The round struck the top of the berm, a good distance over the target. She recovered nicely and finished the drill. She transitioned back to her rifle, reloaded it, and then immediately used it to engage several more targets.
Afterward, I asked her about the AD. She was trying to catch the link after the second shot, and it just caught her by surprise. No harm done, but here is the point:
The industry standard for pull-weight on triggers of production pistols is currently 6 to 7 pounds. I think that is about right. I’m sure it’s too heavy in the minds of some, too light for others. While I think 12-pound triggers exhibited by the NY2 Glock Trigger Modification are needlessly heavy. I’m not comfortable with triggers any lighter than 6 pounds, owing to the foregoing.
I consider myself a reasonably competent operator, and I carry routinely. All my carry pistols comply with the foregoing industry standard. 3-pound, or lighter, triggers have no place in my life!
The term, “hair trigger,” has an inherently malignant and unsafe ring to it, particularly among the ignorant. It is predictable that a prosecutor or plaintiff’s attorney will use that term, ad nauseam, when doing his best to establish your “reckless disregard” for the safety of others, when he is able to show that your firearm has a significantly lighter trigger than it did when it emerged from the factory, a modification for which you arranged, not the manufacturer.
In addition, during a real fight, the fine motor coordination necessary to realize what scant speed/accuracy advantage of which a light trigger may be capable, will likely all be a moot point anyway!
My conclusion is that over-tuning of serious guns is folly, dangerous folly! When an out-of-the-box pistol has a trigger that is too heavy for your taste, the best strategy is to look at something else, rather than tinker with what the factory produced.
These comments on the subject were sent to me from a colleague:
“I put an aftermarket, 3.5 pound connector on my Glock, and really liked it. Then one day, shooting in cold weather, with gloves, I realized I could hardly feel the trigger. I have since come to my senses, put the original connector back in, and re-learned to use it properly.”
My friend and colleague, Pat Sweeney, puts it best, as he usually does!
“In writing ‘The 1911: the First Hundred Years’ I had a chance to handle some very early 1911s, pre WWI! They are startling, in that they all have (at least by some standards) ‘heavy’ triggers, 6 to 7 pounds, but crisp and clean. You press the trigger to take up the slack. The trigger stops. Keep pressing, and 6 to 7 pounds later, the hammer falls. You can put a lot of bad guys in the ground, with a trigger like that!”
You bet you can, and all with no ADs, even when in a cold, muddy ditch, at night, in the rain, with bullets whizzing by your ears. That’s what pistols are for!
While more training helps with lighter pulls, it also makes lighter pulls less meaningful to performance, and I don’t see training making any difference on this particular issue in court.
Pull weight goes gun by gun, and seems to come down to manufacturer spec, common custom and practice, or both. If Walther puts a 4.5 [pound trigger] into their new striker-fired pistol and calls it good, the user will be more protected than if he put a factory-forbidden 4.5 in his Glock, and the same 4.5 pound pull is well within spec by any standard for the 1911. Go figure.
I have worked in many cases, both civil and criminal, in which trigger pull weight has been an issue, including at least two cases in which the opposition sought to argue that a handgun had a “hair trigger,” a sensational term lacking any technical definition. I’ve also worked in a good number of cases in which the phenomenon of involuntary muscular contraction as a possible cause of unintentional discharge has been an issue, and I have written several articles and taught widely on that topic for over 20 years. I’m currently working on a police shooting case where the deceased had an AR-15 with a 2.5 pound trigger pull that seems to be the result of home gun smithing, to the point where the rifle is unsafe to use for that and several other reasons.
One can extrapolate from my Glock recommendations to other brands of striker-fired and double action only (DAO) pistols; a pistol with no manual safety, a healthy amount of trigger travel, and a pull weight in the range of about 5.5 to 8.5 pounds is fine for a defensive handgun of these action types. Single-action/double-action semi-autos with double action (DA) pulls of 8 to 11 pounds, and single action (SA) pulls in the 4 to 6 pound range are fine. Revolvers with DA pulls of 8.5 to 11 pounds are fine. The DA revolver’s SA trigger pull weight doesn’t concern me much, because I think revolvers should rarely ever be fired single action in defensive use, but 3.5 pounds is the industry’s minimum standard here. When I carry a revolver, it’s usually a double action only.
As to whether a highly trained individual can reasonably use a lighter, shorter trigger pull, my opinion is that almost none of us are as highly skilled as we like to think we are. Keep the game guns (and the tactics that go along with them) separate from the serious weapons.
About 400 years ago, Miyamoto Musashi cautioned us, “Weapons should be sturdy, not decorative.” Words to live by. I am willing, however, to have a trigger pull lightened, within reason, for use by an individual whose hand size and strength don’t allow a heavier pull to be used effectively. But before lightening the pull for such a shooter I would try to find a handgun with a shorter reach to the trigger, smaller grip circumference, etc., even as a custom option if necessary.
Network board member and trial attorney James Fleming did some research for us into court cases in which the question of light triggers arose. This is what he wrote:
Boy, is this not an easy question to work with. Good luck on the article. Gleaning nationwide cases, here is one illustrative case from California from 2008, a civil action:
Max Birchfield died after a handgun he was holding discharged, apparently accidently, and shot him in the chest. This happened in the bedroom of Leandra Sweatt, Max’s girlfriend, who had been given or lent the gun by her father, Charles Sweatt, to use for self defense. When he gave Leandra the gun, Charles knew it had a hair trigger-it could be fired with substantially less pressure on the trigger than an average gun of its type.
The court found–
“We will begin by assuming some outer boundaries for the sake of argument. We will take it as given that the donor of a well-maintained, properly functioning handgun with an average trigger pull weight has no duty of care to persons injured by accidental discharges occurring after the gun passes out of the donor’s control, so long as the donee is competent. On the other hand, we will assume for the sake of argument that if a donor of a gun knows it is defective and has a tendency to blow up in the user’s hand, causing injury, then he has a duty of care to persons foreseeably injured.
“The hair-trigger gun at issue here is somewhere between these outer boundaries. According to plaintiffs’ expert, the trigger pressure necessary to fire the gun was less than one pound, which was less than half of the pressure typically required for guns of its type. In addition to saying, as we have noted, that this was similar to the amount of pressure needed to click a ball-point pen, the expert also opined as follows:
“That trigger pull is considered to be extremely light, and is dangerous in function. [¶] One pound of force could have been easily applied to the trigger of the weapon accidentally, e.g., one could have inserted a finger into the trigger guard area and applied that amount of force by brushing the finger against the trigger without an intent to discharge the weapon. (The trigger guard is a band of metal which encircles the trigger.) [¶] Also, a weapon which can be discharged with such little force is subject to other types of accidental discharge.
In effect, the light trigger pull renders the trigger guard less effective; a glancing blow, an unintentional touch could cause the weapon to discharge. Normally, the trigger guard will prevent many of those types of accidents.”
“Cases from other jurisdictions dealing with accidental discharges allegedly caused by light trigger pull weights can also help give an idea of how dangerous the hair trigger here was. In DeRosa v. Remington Arms Co., Inc. (E.D.N.Y. 1981) 509 F.Supp. 762, a products liability case, Judge Weinstein ruled that a police shotgun with a trigger pull weight of 4.5 pounds, which was within the industry guideline of 3 and 3.25 pounds to 6.5 pounds, was not unreasonably dangerous. (Id. at pp. 764, 768.) By contrast, in Hines v. Remington Arms Co., Inc. (La.App. 1993), reversed in part on other grounds in Hines v. Remington Arms Co., Inc. (La. 1994) 648 So.2d 331, another products liability case, the court held that a competition target-shooting rifle with a 2-ounce trigger pull weight was unreasonably dangerous per se. (Hines v. Remington Arms. Co., Inc., supra, 630 So.2d at pp. 813, 814.)
“All this, of course, provides only a rough approximation of how dangerous the gun was and leaves us with a judgment to make. Helpful for this purpose is the series of California cases dealing with when a vehicle owner who leaves the keys in the ignition has a duty to third parties injured by negligent operation by a thief or other unauthorized person who uses the vehicle. These cases provide a scale of degrees of dangerousness against which we can measure our case by analogy.” (Which is utter bull poop, of course, but is an example of how courts can twist reality to arrive at the desired decision. Car thief, and light trigger pull weight are analogous?)
Consider this from Louisiana:
Willy shot Taffy, his girlfriend, and tried to claim it was an accident. (Actually he shot her with a .40 cal. and then told her father she was “just faking it” as she lay on the floor of the garage bleeding out, so we are not dealing with a rocket scientist here).
“Again, the evidence established that Ms. Hargrove was in a defensive posture at the time of the shooting and that the bullet did not ricochet off of any other object or surface prior to hitting her, indicating a straight-on shot. Mr. Hargrove testified that Defendant fled the scene immediately, which further allows for an inference of guilt. Testimony was introduced to the effect that .40 caliber weapons generally have a trigger pull weight which greatly reduces the chances of accidental discharge and that, generally, an individual has to have intent to pull the trigger of a .40 caliber weapon.** Finally, Ms. Hargrove stated that Defendant ‘just shot me.’ This evidence as a whole indicates that the gun was not discharged by accident.
**Corporal Walls allowed that it would be possible for a .40 caliber weapon to accidentally discharge. He also noted, however, that “pull pressures” are normally assigned to triggers in order to prevent accidental discharge and that, absent another object having lodged on the trigger (such as a tree branch), an individual would “have to have intent” to pull the trigger of a .40 caliber weapon.
There are 3 or 4 others, all of them accidental discharge defenses. I found no reported appellate cases where any discussion on this issue occurred in the context of a self-defense case, nor would I expect to. In order to claim self-defense, you must admit that you purposefully shot an assailant. If you intended to do so, the pull weight of the trigger and the extent of one’s training are largely irrelevant. (“Pull weight schmull weight, it would not have mattered if it had a 15-pound trigger pull. I shot the SOB until he stopped trying to kill me...”) It won’t keep some enterprising prosecutor from bleating about it in court, creating an issue to confuse a jury already drowning in facts and bullets and blood, which is never a good idea. And there is no way of knowing how many cases at the trial level there are out there where this precise thing has happened.
So, personally, if anyone asks me, I tell them never to screw around with the pull weight on a self-defense trigger, or if they simply must, have it done by a professional gunsmith, and keep it within factory recommendations.
Lastly, I reached out to my friend Clint Smith, of Thunder Ranch fame. When asked what the trigger pull weight of a 1911 should be, he responded succinctly, “4 pounds, clean break.”
Hand Loaded Self-Defense Ammunition
Although most well-educated armed citizens have over time come to understand the arguments against using hand loaded ammunition for self defense, the question still comes up from time to time. In over half of the firearms-related cases on which I have worked as an expert, I ended up doing some type of ballistic testing involving either a recoil/ejection pattern test or a gunshot residue/stippling test.
The protocols for these tests are outlined in shooting incident reconstruction textbooks, all of which indicate that the very same type of ammunition must be used to render the tests credible. If I am the expert witness on a case that requires ballistic testing, I hope that the ammunition needed is readily available. If you are using your own hand loads, any testing I might do would be suspect, because even if you supplied hand loads from the same batch as that of the subject ammunition, the question could be raised as to legitimacy of that testing. A skilled reloader could even fashion a hand load to show the same stippling pattern as that discovered as evidence at the scene, but fired from a different distance.
Consequently, it is very important for the paid expert of an innocent defendant in a criminal prosecution to be able to perform ballistic tests with the same ammunition as was used in the shooting. This is the real argument against using hand loads for self defense.
How can members of the Network prevent falling prey to the misleading and distracting accusations a prosecutor may make about their defense gun or ammunition? To summarize–
1) On a production gun (not a custom gun), leave the trigger pull weight alone.
If you want a lighter trigger, get a different gun, but don’t lighten the trigger below the factory settings. Smoothing the trigger pull and eliminating over travel should be fine, as long as you don’t lighten the pull weight.
2) If using a high-end custom pistol, a 4-pound trigger pull weight is the industry standard, and anything lighter could be argued as unreasonable. For folks like Scott, why not set up another Wilson Combat 1911 pistol with a 4- to 5-pound trigger and use that one for self-defense, and the other for the range? What a great excuse to buy another gun!
3) If you modify your gun it is best to have that modification performed by a competent gunsmith, one who will be willing to go to court and testify why he performed the modification. You had better be personally prepared to logically explain why that modification was done, too.
4) Never deactivate a safety device on a gun you use for self defense. If you just cannot live with whatever safety device you want to deactivate, then simply change to a different weapon type that does not have that feature.
5) Use only factory ammunition for self defense and buy it in sufficient quantity that if exemplars are needed for testing, they are available.
6) Leave the cute, custom paint jobs, engraving and cartoon logos off your serious self-defense guns. The place for those affectations is at the range, not in the courtroom.
In closing, when pondering any question about self-defense equipment, use your God-given common sense. When I was in a position to command law enforcement officers, I would tell them, “If whatever you are thinking of doing is possibly a bad idea, then it probably is a bad idea. Don’t do it.”
To apply that logic to self-defense gun modifications, I’d say, “If you have to ask whether a modification or alteration to your pistol will hurt you in court, it probably will.”