Do an internet search of the first five words of this post’s title.  You will get enough distinct hits for days of reading, as a hundred or more (in the first thousand or so) appear to contain substantive material worthy of consideration.  In short, longstanding advice — from homicide investigators, prosecutors, defense lawyers, gun writers, bloggers, the self-defense firearms community, and those who actually consult and testify as experts in criminal and civil trials — urges (prudently) leaving a defensive handgun factory box stock, to avoid adverse consequences in a legal proceeding.  Critics of such advice note (correctly) a near dearth of anecdotal trial reports and published appellate decisions suggesting there are adverse legal ramifications on account of modification to or installation of a non-factory standard replacement part (NFSRP) into a defensive handgun.  So, are there legal ramifications or not?  Yes, there can be.  Are they adverse?  Perhaps.  Should one then automatically forgo a useful, desirable, and common handgun modification or NFSRP?  Probably not.

Some discussion parameters. Any modification or NFSRP which is colored/finished other than with justifiable utilitarian purpose, rightfully argued as making a handgun unsafe, sold as or carries a name, logo, or other identifier exploiting a perceived legal loophole, lack of political correctness, or touts sex, drugs, rock, or killing (e.g., Rambo, Grim Reaper, Zombies), whether ostensibly righteous or not, or urges vigilante-like (e.g., “Punisher”) behavior, should be dismissed as off limits for a defensive handgun.  Accordingly, they are excluded from the discussion here, as are modifications and NFSRPs installed by a manufacturer or agency armorer based on agency or department specifications.  Also excluded are aftermarket grip panels and sleeves, “iron” and “night” sights, white lights, and lasers, as I believe their use is so pervasive that their existence and purpose are nearly universally acknowledged and accepted.  I note some will disagree with my take on lasers, and others will have no issue whatsoever with fiber-optic sights, for which I harbor a small residual concern (which is rapidly disappearing as more defensive handguns come with those installed by a factory or custom shop).

What about a lightened or more crisp trigger pull, modifications which seem to generate the most debate?  Unless the shooting in question was or is alleged to be the result of an unintended discharge, trigger characteristics ought not to matter.  But I would nevertheless advise (absent a very good reason to do otherwise) against going any lighter than a bit just north of what expert gunsmiths and trainers familiar with the particular handgun platform believe is appropriate. That implicitly means going with parts which are sold for “defensive carry” or “duty,” and straying away from gunsmith modifications and trigger group parts identified as used for “competition.”

I acknowledge (and accept for myself) that a mild level of uncertainty will always persist as to whether a modification or installation of a NFSRP might (undeservedly) contribute to an adverse result in an otherwise “good” officer-involved or self defense shooting. Stated another way, is a prosecutor or civil plaintiff handed a “better” case, even when (as will almost always be the case) the modification/NFSRP is clearly irrelevant to what precipitated the shooting or its outcome, and therefore, its legality. The answer is they might, if the evidence gatekeeper, the judge, foolishly allows such into evidence and then compounds the error by allowing an erroneous, completely subjective opening statement or closing argument about it, which gunnies easily recognize as nonsense, but which a trial jury or an appellate court in review might not.

In the case of a criminal prosecution, the entire dynamic of a trial may be changed.  Here’s why.  LE shooting investigators, prosecutors, firearm examiners, judges, and juries are rarely gun modification or replacement part savvy.  They may, on a lawyer’s urgings, erroneously think a modification or NFSRP is relevant to a disputed fact. Or, they may feel such reflects an unseemly (i.e., guilty) mindset of the shooter/defendant.  In order to defend against such “evidence,” a countering explanation of the modification or NFSRP’s purpose/function must be tendered.  How is this done? Likely the first attempt will be before trial, by motion to exclude such evidence. What and who your lawyer offers to do that depends on why and how and by whom the modification was made or the NFSRP installed.  (It could matter whether the modification or installation of the NFSRP was made at the time of manufacture (e.g., at your request from a list of customer options), is part of a special edition model, or is something done after the purchase by someone other than the original manufacturer, including the gun’s owner).

If you gunsmithed the alteration or installed the NFSRP, you may need (as the best and/or only witness allowed) to testify and be the witness who introduces what material you relied on to choose the modification or NFSRP and why it was done.  That can compel a completely different strategy in a criminal case where you as defendant cannot be called as a witness by the prosecution.  In a criminal case, once you testify, you are fair game for just about any cross-examination.  A jury might be inclined to believe you acted lawfully, but if they disbelieve any portion of your testimony, even something which isn’t dispositive, you might suffer an adverse result.

If someone else did the gunsmithing, you need to ask will that gunsmith or the part’s promotional material (or its inventor) be available/admissible to explain and will it/they make a positive impression on a judge/jury?  Another point, maybe applicable in all cases — are there independent experts or a manufacturer’s engineer available and willing to testify as to the righteous utility and general acceptance of the modification or NFSRP?  (Note, your attorney may not be able to compel an unwilling witness’s attendance across state lines without special proceedings).

I believe there are many modifications and replacement parts which, if you are inclined to depart from factory stock, should give you little pause.  Examples include those which: Facilitate left-handed or ambidextrous use; are replacement parts very commonly installed on a given platform for operational ease or improved service life or reliability (e.g., Wilson Bullet Proof® or 10-8 Performance 1911 parts); address design issues (e.g., grip plugs for Glocks); modify trigger reach for small or large hands; improve magazine base pads (but do not add capacity); correct a documented factory function shortcoming (e.g., redesigned extractor, metal magazine release to replace factory polymer); customize grip and trigger guard for better fit/grip or recoil reduction (e.g., contours, texture, and reduction).  How about a modification or a NFSRP which is perceived to have the sole or dominant purpose to increase shooting or reloading speed (e.g., lightening slide cuts, magazine release buttons, magwells) or accuracy (e.g., match barrel/bushing)? A bit more pause for the former, none for the latter. For sure, my observations are personal and subjective, since I am a frequent user of those (except slide cuts).

Executive takeaway: Consider the possible arguments — pro and con. Proceed cautiously, but don’t feel pressured not to modify/install what has utilitarian purpose and will be meaningfully helpful to the success of your likely mission, that is, the feared events which compelled you to own/carry the handgun in the first place.  Never forget success in a gunfight is almost always more dependent on mind, mindset, and skill, than on equipment.  Pay particular attention to what an NFSRP is named/nicknamed, how it is advertised, the nature of its users (is it primarily LEOs, gamers, competitors, genuinely self-defense minded owners, respected trainers), the handgun manufacturer’s recommendations and expectations regarding modifications, and what gunny brethren say about it (both the true and the false) in internet forums.  Then decide whether you wish to engage the risk, however certain or debatable. Next, decide whether you or a professional should do the gunsmithing or part replacement.  But bear in mind regardless of who does the modification or installs an NFSRP, and whether or not the modification or part is truly sensible and defensible, there is nevertheless a chance someone (preferably one knowledgeable and presentable, but usually not you) will need to explain/justify the what, how, and why here:

A final point. I have been asked from time to time about the LEO allowed to carry a personally owned “off-duty” handgun without restrictions, who carries the same make/model as his/her issued duty handgun, but makes modifications or installs an NFSRP not allowed by the agency for duty weapons.  I have quickly advised against that, because it might result in the agency determining the LEO should not be provided paid defense counsel, and of course, the deviation from agency policy could be seen as an invitation to civil suit by a lawyer who has unbilled time on his/her hands.  I would like to hear from MSW followers (who are LEOs) on this.



This entry was posted in Legal, Modern Service Pistols, Weapon Modifications by Steven Harris. Bookmark the permalink.

About Steven Harris

Steve Harris is an experienced attorney (member of Florida Bar, 1979) who has represented federal agents and local LEOs in duty related matters. He has written and lectured about officer involved shootings, self-defense, and use of force law, including "Stand Your Ground." Steve has been a seasoned and active competitive handgun shooter for over 20 years.


  1. Steve this had been an on going debate with me and customers, students for awhile. My thoughts on this matter is this.Our world has changed so so much, the good bad and the ugly rule our world every day, so with that when I see students with skulls and phrases on personal carry guns I tell them that they can do anything they want to there tool, but remember that after you pull that trigger on someone for the wrong or right reasons be prepared to here from the other side why you carried a death dealer for protection. RIGHT OR WRONG.

    • Everyone needs to remember that even if the battle of firearm experts does not ensue in the courtroom, the jury will likely have time to see/inspect the defendant’s pistol. One or more of the jurors may notice something about it, or have heard what seemed then to be innocuous testimony of an LEO or firearms examiner that the particular pistol is different that what LEOs carry.

  2. I live in the anti gun North East. Many major Depts. in my State do not allow off duty gun ownership or carry other than issued firearm. State law does not allow officers to personally own high capacity magazines (must be issued by the Dept.) or AR15 type rifles which are considered assault weapons. Our own LEOSA standard requires retired officers to have a gun permit (LTC class A.) I have no doubt that any modifications to a firearm would put the officer in a bad light, with the Dept. and the prosecutor. Also there was a case, years ago just North of my State, where a Hampton NH Sergeant was prosecuted for an AD during an arrest where he used a personally owned 1911. The gun was authorized but much was made out of him carrying a larger caliber than issued.

    • Could you provide us with a list of MA PDs that don’t allow off-duty gun ownership? I’ve never heard of one.

      • MA State Police for one. Many cities and towns do not allow allow officers to use any other firearm other than the issued one, on or off duty. Officers in those Dept. that carry other than issued will not be indemnified by the PD should they use the firearm as an LEO. Also it would go against policy and procedure and the Officer could face Dept. sanctions even though the UOF was deemed justified by the DA’s Office. I know that many small towns (ten or less officers) are not State accreditated and do allow off duty guns.

  3. If you watched the Zimmerman trial you would have seen some testimony regarding the firearm. I believe the link below has it.

    There was discussion regarding the trigger pull weight and other characteristics of the gun. That being said, all of that testimony from the expert witness could be negated with an expert witness of your own and a good lawyer who has an understanding of how firearms work and the appropriate questions to ask on cross examination.

    My .02 is that modifications to a firearm are acceptable within reason. Your article does a good job of discussing what is within reason. At the end of the day, if the shooting is justified, with competent counsel you should prevail in a courtroom. Firearm modifications shouldn’t hurt you if you were legally justified in employing deadly force to stop a threat.

    • In a more recent Florida trial (Dunn) where the defendant was charged with first degree murder and convicted of lesser charges, the prosecutor argued (in support of premeditation) that the pistol (Taurus) had a six pound trigger pull. Thus, he said, the 10 shots taken required 60 pounds of deliberate strength. I had not heard that before, but I suspect other lawyers have argued similarly.

    • I would add a caveat to your statement: “Firearm modifications shouldn’t hurt you if you were legally justified in employing deadly force to stop a threat…..

      unless political considerations are more important to the prosecutor.”

      DA’s are elected officials and they want to keep their job. Also lawyers pride themselves on being able to argue both sides of a case. What makes you think they won’t throw anything up just to see what sticks?

      • I’m not saying the argument won’t be made. I’m saying with competent counsel that kind of argument should be negated. In theory anyway. No one really knows how a jury will react.

        • I’ve been through a civil tort, I won, but it was still horrible to go through. Don’t give the attorneys any more “ammunition” than you have to. I went through hours of anguish over how I parked my cruiser vs how we were taught to do it in the academy (angle and distance.) Just because you can justify something doesn’t mean you can sell it to the plumber or housewife sitting on the jury. I’d rather learn to use the tools I was issued.

  4. I’m thinking the Ghost 3.5 (or other brand) trigger connector &/or springs would be a great example or a possible issue?

  5. Nice article Steve.

    The most debate I have seen on this matter is the glock “-” connector which comes from the factory in the glock 34 or glock35. People using the same “-” connector in a glock 19 or 17 could it still be a liability even though the part is a factory part?

    • See answer on the Ghost 3.5. An attorney might ask you to explain about any sales/availability restrictions Glock imposes on the minus connectors and why they come standard on only “competition” and “tactical” pistols. (I think that is the situation). Is there an official Glock explanation somewhere which might be a incitement to making it an issue?

      • I strongly suspect that Glock doesn’t sell minus connectors in the US because it’s cheaper to do so than to deal with more lawsuits.

    • The “-” connector is factory standard on the G34-G35, which were designed around USPSA production division (sometimes referred to as “gamer guns”). Since you are grabbing a part off of a “competition” trigger,* expect to have to fight that battle if you ever have to use it.

      Without replacing any parts, a Glock owner can get a lot of mileage out of polishing some metal parts of the trigger assembly and the striker — the trigger weight will be the same, but it will be a lot smoother and crisper. Online, is often called “the 25 cent trigger job.” There would appear to be less legal risk since all you have essentially done is clean some parts.

      * I am unable to say the words “stock G35 trigger” and “competitive” in the same sentence with a straight face. In your defense, you might raise the fact that _everyone_ shooting a G34-G35 replaces the springs with lighter ones within their first few USPSA matches, which makes a far bigger difference than the connector.

      • The minus connector is also standard on the G41, which is marketed as a comp/duty pistol.

        I have trouble believing a competent attorney couldn’t draw a parallel between duty and CCW use.

  6. My first agency, one of the biggest in Texas, did allow privately owned carry. The privately owned weapon had to be of a particular make (the same as the dept. issued), model, caliber and action. The only items we could switch out from factory were the install of night sights, grips (with restrictions), and high cap magazines (as long as they were factory stamped). The personally owned pistols were inspected every year just like everyone else. We were told being required to stay within the issued manufacturer is only for logistics so the armorers don’t have to keep spare parts for X amount of other manufacturers.
    Patrol Rifles could be privately owned and used for duty. Again restrictions on make, model. All after market parts has to be approved by the range staff. The range staff maintained a list of approved equipment (from holsters, optics, ammo, parts, etc.).

    My current agency allows privately owned pistols for duty. I do carry a privately owned pistol, a completely stock Sig P226 with SRT trigger (I feel there is no need to modify that pistol). The restrictions are limited to certain calibers, barrel length, night sights are required, round capacity, and no SA revolvers. Trigger weight must be within factory spec for that particular pistol. Pistols are inspected every year for non-factory modifications. The only thing we can swap out are grips (with restrictions).
    All rifles are issued by the dept. to every officer equipped with BUIS and Aimpoint. Patrol cannot modify triggers or internals. Just about everything else can be: stocks, handguards, light mounts, grips, charging handles. Aftermarket parts are supposed to be approved case by case basis, and installed by a dept. armorer. I was told the restrictions were for liability but with enough room to allow officers to set up their rifles to work for them.

  7. You tell me. I can see the following questions being asked you:
    What is a “Ghost 3.5” connector?
    What does its name mean?
    Who uses such a product?
    Does it impart a 3.5 pound pull which is lighter than factory trigger pull?
    What is the purpose of having less than a factory trigger weight?
    What is the trigger pull weight of a factory Glock? Your gun?
    Who put it on?
    For what purpose?
    Does Glock make a similar part?
    If yes, why didn’t you use the Glock part?
    If no, or not available, why not?
    What effect does the use of this part have on your gun’s warranty?
    Is this modification approved by Glock?
    Are you a Ghost/Glock armorer?
    (Disclosure: I had that part on a first generation Glock 19, many years ago; lost not a moment’s sleep over it). But that was then.

  8. Something I didt see mentioned: painting the front sight dot a highly visible color; ie, using a super bright orange nail polish on a carry gun’s front sight.

    • I should have mentioned paint with my perceived no issue sight modifications.

    • If someone is considering neon nail polish, I would encourage them to look at fiber as an alternative. As mentioned in the article, fiber-optic front sights have become very common; those are typically packaged with replacement green and red fiber that can be easily installed by the user.
      In addition to the contrasting color, another advantage is that the fiber’s brightness adjusts based upon the ambient light so it is bright during the day without being blinding at night.

  9. My idiot nephew is currently engaged in a criminal trial in California for stabbing a guy who was choking him and actively trying to kill him. My brother in law is paying $8,000+ for a use of force expert to show up and testify. If you’ve got that kind of money to pay, plus lawyer’s retainer and fees, and plus a medical expert on wounds then modify away. I would be very very careful.

  10. In the Alvarez case in Miami in the early 80s, State Attorney (at the time) Janet Reno’s Office made a big deal in court about the trigger spring in Alvarez’ pistol having had coils removed to lighten the trigger pull weight. The defense put the officer (an S&W trained armored IIRC) who made the modification on the stand to testify that it was an S&W approved modification. Alvarez was acquitted.

    • Mike — thanks for mentioning the Alvarez case. It is a great example of the complexities involved when a handgun has been “modified.” You can read about the case in noted defense attorney Roy Black’s book “Black’s Law.” Amazon — buy it here:

      I have asked two people I know who were directly involved in the case to help refresh my memory. I await their answers. In the meantime, as I recall it, Officer Alvarez had a modified S&W Model 64 revolver. He first claimed his SA shot was an unintended discharge when his arm was bumped, later that he shot in self-defense against an armed noncompliant.

      I think he may have done the spring modification himself, and also testified. I think the grips on his revolver were also challenged and had to be supported by expert testimony; I am thinking it may have been (FBI retired) Bill Rogers. Alvarez had great lawyers and experts, but acquittal was still far from certain.

      Also note I understand if you send an S&W revolver to the company for service, they will restore it all to factory specifications before returning it, and today they do not consider cutting spring coils an acceptable modification. I doubt anybody would endorse cutting coils today, especially since various reduced springs are available from Wolff.

        • Another trick used back in the day was to back out the screw on the front of the grip to lighten the trigger pull. I carried a Colt Python and it didn’t need any trigger work.

      • Actually, according to Black’s book, Alvarez had used a non-licensed gunsmith to perform minor trigger modifications, and that gunsmith had done similar modifications for quite a few officers from the department. The prosecution “encouraged” the gunsmith to testify against Alvarez presumably under the threat of prosecution for gunsmithing without a license. If I remember correctly, Bill Rogers did indeed testify in this case. The defense in this case did an exceptional job where the odds were quite stacked against Alvarez.

        • In those days, with Janet Reno as State Attorney, a policeman’s lot in Miami was not a happy one.

        • Roy’s book explains the difficulty facing off with a state’s alleged police expert who offers opinion testimony (that is laughable to real LEOs and gunnies, as suggested in the post). I think we have come a long way in the area of expert testimony. Jurors hopefully would reject an “expert’s” nonsense today as they did 30 years ago. In the Zimmerman case, one of the defense experts seemed woefully under-qualified on paper. But he held his own and helped a great deal. Maybe a lesson for trial lawyers.

  11. Always thought about this when it came to installing the Apex DCAEK in my Shield. I want a more glock style trigger terribly bad, but am just a little cautious about doing any modifications.

  12. Having spent the weekend at a training class and having the opportunity to shoot a couple of highly tuned and out right custom Glocks, I have to say that although the triggers were sweet, I was able to miss just as well as I could with my stock M&P 9 (Heinie sights) as I could with the $3000+ pistol when I was moving too fast and not getting my sights properly aligned. The triggers on most of these popular polymer pistols clean up, some respectably after a few rounds ans some generous lube. While I realize that we all feel we have to stoke our egos by customizing our carry guns or being able to brag about the nice trigger group we dropped in, but in reality, we”re just as well served with factory spec EDCs.

  13. Here’s my thought. If modifications are considered in a justifiable shooting why not caliber? If you own a .380, a 9mm and a .45 that you have a choice of for carry shouldn’t people be worried that a DA will make hay that you carried and used the .45? How about Home Defense? So you used a 12 gauge with 00 buck instead of a .22. If it’s true most people are killed with a .22 couldn’t that be used by a DA that you didn’t intend to “stop the threat” but intended to kill them by using a more deadly round?

    I am fairly firmly in the camp that your defense should be once use of deadly force is met it shouldn’t matter if you used a firearm, machete, or a bulldozer.

    • I am not an attorney but there are documented cases where seemingly innocuous modifications became an issue, painting the defendant in a certain light. Steve Harris, however, -is- an attorney and it would be prudent to consider the points he make in his article.

      • Do you have a link to these documented cases? Did the claims have a significant outcome on the trial?

        I still find it very odd people are concerned about trigger jobs but there is no concern over using .357 instead of .38.

  14. The only changes to my duty pistols over the years were grips (broke the originals on 1 pistol) and sights (night sights are my friend, though after nearly 30 years of carrying night sighted pistols I’m wondering if my side will start to glow at some point).

    The 1911 I carry when off duty was by a trained gunsmith. The internals and grips were replaced because the gun was made in 1943 and had lived a hard life. The trigger pull weight is within factory specs and it sports nights sights as the only part that wouldn’t have been available with it was made.

  15. Adding to what has already been touched on in this discussion, where you live in the country could have a very significant impact on whether or not firearms mods lead to vicious, opportunistic prosecutions of individuals involved in legitimate self-defense shootings. As a current resident of Northwest Florida, I was surprised to learn from my shooting instructor that my super-light, 3.5 pound tricked out Glock trigger job would lead to certain prosecution for murder if used in a justified shooting (I promptly switched it back to factory parts with the $.25 trigger job). Lesson learned: know the state of political affairs regarding the use of deadly force involving modified firearms BEFORE you end up in the position to use them. Also, as a refugee from New York State, I can tell you that if you live in a socialist state, you would be very wise to stay away from ANY aftermarket modifications other than night sights on a self-defense gun (preferably OEM factory installed). This is because district attorneys in those states would love NOTHING more than to put innocent gun owners, who are scapegoated and treated as criminals, away for life for justified self-defense.

  16. As a detective who has shot bag guys and investigated shootings, and a NIJ trained Firearms Examiner, the presence of modifications/aftermarket accessories has rarely come up short of the question of illegal modification to serial number, and trigger mech to full auto. My old department actually encouraged and supplied 3# trigger connectors for Glock shooters (at the time it was BYOG).

    We have had guns with lasers, lights, trigger mods, and the like involved in shooting investigations and it is rarely discussed. Our bottom line is if it’s a good shoot it’s a good shoot, be it with a 22 short or a 500 mag. I have never heard of a suit or defense argument based on the shooter in a self-defense situation having a gun with any mods in our area.

    Personally I would rather answer questions about a trigger mod and laser sight than throw a round and hit a bystander.

    Keep in mind I’m north of the shitpit named New Orleans in the Deep South. Your local LE agencies may have different opinions.

  17. There are a lot of things that could play into a jury’s decision in a criminal or civil suit.

    Example – recently declined approval for duty use of a AR pattern rifle.

    Among the many reasons, were the markings for the selector switch positions: “Live” vice “Safe”, and “Dead” vice “Fire”.

    At a minimum, this could damage one’s credibility by the less than profession appearance.

  18. I always advise my Ohio CCW students to stick with factory stock firearms and factory ammo for concealed carry for the reasons you mentioned… I think things like sight paint, even replacement sights would pass scrutiny along with grip tape, etc…

    I also tell them to think carefully about their “visual presence” both in real life and online… “Kill’em all and let God sort’em out” stickers and signs on your truck or garage will play into your prosecutions and/defense if you have a self-defense shooting that is questionable or that a prosecutor wants to pursue for some other reason… it’s happened here locally… photos of bumper sticker on defendant’s vehicle entered into evidence in an assault case…

    Good thoughts in your write-up…

    Dann in Ohio

  19. Without getting into a debate about NIJ standards; it can’t hurt to carry an NIJ compliant pistol. I think that relying on those standards would be a pretty strong starting point in court.

    • I assume what you mean by NIJ compliant is NIJ Standard-0112.03, if this is the current standards:

      I do not know what manufacturers reflect that their pistol has been determined to be NIJ compliant, but it seems from the standards most quality pistols in stock form would be compliant, and most of the modifications I mentioned would not render them non-compliant. Of course, I suspect making any modification puts a particular pistol technically no longer compliant.

  20. One question I would have would be in reference to caliber conversions.

    What would be the possible legal issues with converting to/from .40S&W to/from .357SIG? I ask because I carry a sig 239 in both .40 and .357 configuration. Both configurations use factory parts, but what if I wanted to convert my XD40 sub compact to .357 because I just don’t care too much for .40 and it’s terminal ballistics offerings?

  21. I cannot think of any adverse legal ramifications from a factory blessed barrel change. Nor from the use of .357SIG. But you should be prepared to explain when/why you select each caliber. (BTW, I don’t care for .40 either).

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