M*CARBO Brotherhood

How Low Can Trigger Pull Be Reduced?

I found the magic KEY


Dang, that is light! I’m not sure if I’d like a trigger that light on a carbine like this. LOL


The nice thing about it is that it is now so smooth I can bring the sear to the breaking point let go of the trigger and come back and bump it OFF any time.The surfaces have not been changed just super polished. The edges of the bearing surfaces are the key !
Total trigger travel is just under a 1 /4". it seemed like as lower the pull got the travel got less.
My Geisselle on my TAVOR is 3lb 2oz.

It is all about gun control !!!:sunglasses:


i now have a choice to take up on the trigger and do a full release. or do a “set trigger” go to safe and be still, “on safe” til time comes to fire, a single shot. The pull at that point is as pictured. I could do the same at 3lb 3oz… Now the travel is less. On set trigger i would say travel is about 1/32" to 1/16".
To be honest I do not think I would do that but it goes to show how much of an improvement the trigger bar is.
The interesting thing is, I think I know how to reset the trigger pull back up if I like.
I have spent almost 18 hours since Friday working on this.

The MCARBO trigger bar is doing it’s job very well !!!

trigger pre travel 3/32 and another about 3/32 for release


Jefft1967, have you gotten an answer to your question?


Yes a long time ago like you I believed that you can reduce trigger pull down very low the day the trigger bar went on sale I ordered it and all the other parts I had been ordering and did one big install pro trigger job recoiles charge handle the little red donut I did it all then I polished the sear the trigger . The trigger bar I looked at all surfaces metal and plastic I deburred it polished and lubed it for a old fart like me I did a hell of a job am I a gunsmith no but am informed and patient and with iron sights am deadly


this is another good resource for the newbies


This is what I’m getting with my S2K
Average of 10 pulls.

Low pull

Went from a firearm i hated to shoot to one of my favorites after installing the MCARBO all in one trigger kit and trigger bar.


This may be a slightly OT question, but after I installed the pro trigger kit which reduced the pull from over 8 to slightly over 4 pounds (thanks, M*Carbo), some “expert” told me the following. If you are involved in a self-defense scenario and it is found that you altered the trigger from factory specs, besides all your other legal problems the fact that you altered the weapon can add to your woes. True/False/Speculation ??


I’m no attorney or lawyer, so don’t take this as legal advice. But wouldn’t a legal shoot be a legal shoot regardless? If you goofed up does it really matter what you used… a boom stick is a boom stick…


you could deny that you altered it i suppose if thats the case ,and sure if your going to pull the trigger you will pull it no mater what @Steve2q


I would assume who is ever looking at the case would able to tell what is aftermarket. Personally I’m not sure I would use a Sub 2k as a primary personal defense weapon. But if it was all I had and you gotta do what you gotta do, then sure. Yes it’s reliable, even more so after “upgrades”. But I would want as few as many steps as possible between me and a bad guy. Your mileage may vary… There are plenty of members here that have put thousands of rounds down range with their’s and would tell you otherwise.

I guess what I’m getting at is use what you are comfortable with and can safely use. Adrenaline can be a funny thing. If you’re super paranoid get something better and keep it stock.

Again, not a lawyer and by no means should you be taking legal advice from strangers on the internet. I’m sure your laws might be diffeent from mine. Just my 2 cents.


@Steve2q Legal advice is very fact specific and varies from state to state and case to case. I therefore would never give legal advice over the Internet and certainly not based on the limited information you provided. What follows then is just general personal opinion and random observations and should not be relied upon. If you need actual legal advice you should consult a lawyer in your jurisdiction.

Your question really reflects two considerations: 1) the impact of the trigger modification on the Prosecutor decision of whether to file charges – and for what; and 2) the impact of the trigger modification on the deliberations and decision of the Jury. Neither can be judged in isolation but will depend on the totality of the circumstances.

The modification is relevant and admissible to show a possible tendency to shoot first and ask questions later and possibly even the hope that an opportunity will arise to use the firearm in a self-defense scenario – an opportunity not to be wasted on less lethal alternatives once presented. Both sound like a stretch to a seasoned shooter, but the bar for relevance is pretty low.

So let’s return to considerations 1 & 2. Prosecutors have almost unlimited discretion in deciding who and what to charge. And once you are charged with a crime things get dicey. Even if you ultimately are found not guilty you likely will have lost your home to legal fees, any retirement savings will be gone, your job will be long-forgotten and you will be extremely lucky if your family remains intact. Of course, it is even more important not to actually be convicted by the Jury.

This is where the totality of the circumstances comes into play. If the shoot is otherwise clean and the only thing potentially worrisome is the trigger modification, I cannot see anyone other than a politically ambitious, fervently anti-gun Prosecutor in an extremely liberal snowflake jurisdiction actually bringing charges. Even then, few Juries would actually convict; in part because our ambitious Prosecutor would surely insist on trying the case himself (wouldn’t want to miss any media coverage!) and such types are usually totally inept when they actually step into a Courtroom.

Things can change rather quickly with only minor shifts in the facts. Remember that sign in your window that you and your buddies thought was so funny; the one that said, “Intruders please carry ID so we can notify Next of Kin”? The Prosecutor is now looking closely at that sign while reviewing the state statute on the circumstances justifying the use of deadly force. He also is troubled by your ownership of a suppressor, and like many who do not fully appreciate the Second Amendment, wonders why you need an AR-15 and 1500 rounds of ammunition living in a gated urban condominium. A so-called “expert” is examining your firearm, measuring the trigger pull and comparing it to that of a factory issued firearm. His final report will note that you did not just install a replacement trigger kit but spent “what must have been hours” polishing and buffing the various mating surfaces to achieve an even smoother release and lighter pull than even what the stock replacement kit provided.

Well, that should be enough for you to get the idea of how several clearly reasonable and completely innocent facts could combine to lead a Prosecutor to charge someone and might even lead a Jury to convict. Of course, that is solely a personal opinion based on watching multiple episodes of Matlock and that courtroom classic, My Cousin Vinnie, and should not be relied upon as sound legal advice.


Pew_Ding, hunter1916, and JoeFriday…thanks for your replies. The S2K is not my primary defense weapon; I have two different carry guns and neither one has had trigger mods. But like you said, sometimes you gotta grab whats the closest! Yes, a politically ambitious prosecutor can always bring up whatever he/she feels will sway the jury. Fortunately, I live in Florida; a still (relatively) gun-friendly state. Matlock and My Cousin Vinny!! LOL

Vinny Gambini:
I object to this witness being called at this time. We’ve been given no prior notice he’d testify. No discovery of any tests he’s conducted or reports he’s prepared. And as the court is aware, the defense is entitled to advance notice of any witness who will testify, particularly those who will give scientific evidence, so that we may properly prepare for cross-examination, as well as give the defense an opportunity to have the witness’s reports reviewed by a defense expert, who might then be in a position to contradict the veracity of his conclusions.
Judge Chamberlain Haller:
Mr. Gambini?
Vinny Gambini:
Yes sir?
Judge Chamberlain Haller:
Mr. Gambini, that is a lucid, well thought-out, intelligent objection.
Vinny Gambini:
Thank you.
Judge Chamberlain Haller:


being a lil bit of a simi intelligent butt here but this

allows me to stone or have done, a crisp smooth 3.5 trigger pull. with lil chance of repercussions as long as its a clean shoot. I mean, I dont have the strength er…length to pull a heavy trigger…:wink::wink::wink: