Back to that removing the disconnector subject


June 29, 2007, 09:05 AM
Forgive me Mr. Roberts but I know what will happen if you do this to an AR15.

It will not slam fire.
It will not discharge more than one single round.

The semi auto non select fire weapons are designed in such a way that what will happen is that very first round will go bang, the action will cycle, the hammer will follow the bolt home and you will lock the rifle up tighter than you can believe possible.
It will not fire again, you will not be able to cycle the action, you will have a locked up rifle with a live cartridge in the chamber and one very unamused gunsmith telling you this fix isn't going to be cheap because you are an idiot.

I have had some of the best and brightest bring their rifles to me for repair after trying this little Dr. Science experiment.
Take my word, it doesn't do anything but cause frustration and one really pissed off gunsmith.

I should add that when the wizards bring one of these rifles to me I automatically replace the innards before they get the rifle back because I am not going to be responsible for whatever alteration they may have attempted.
That adds, $75.00 for a standard AR15 trigger hammer set-up or $125.00 if you want a Rock River two stage installed.
This is in addition to the money I am going to charge to take the rifle apart and put it back together correctly.
And Man I will charge for this,,,,,,

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June 29, 2007, 10:03 AM
what's the objective of removing the disconnector?

June 29, 2007, 10:20 AM
6 so far this year alone, some times i wish i had a red stamp with de-de-de on it for this stuff.
I got guys from every walk of life doing this.

June 29, 2007, 10:49 AM
what's the objective of removing the disconnector?

Winning an all-expense paid trip to Club Fed.

(in seriousness--because apparently some believe that will make the gun full-auto, which is incorrect)

June 29, 2007, 11:52 AM
Why does the rifle lockup if it did not fire. I at this moment do not have an AR handy to figure out why this happens. If it happened me (And it would not because of my fear of a slam fire) I would just give you the upper and keep the lower at home.

I have observed an AR to double just from having after market trigger-sear springs in them when a 7.62 upper was installed. The same fellow had a registered full auto device for the AR-15 that he installed in different AR and the gun would not fire full auto.

June 29, 2007, 12:50 PM
Sorry, Mr. Roberts, it was not my intention to give a "how-to make a full auto" class. There are very few of the open bolt MACs in circulation and most of those are in the hands of collectors, who have no desire to do anything illegal. The AR mod is potentially dangerous as the weaker primers can rupture under the pressures of a rifle cartridge, with disastrous results. I should have included that part, perhaps, as a reason not to do it, fun or not. Again, it is not my intent for anyone to make any illegal mods.

June 29, 2007, 03:03 PM
The disconnector snags the lower hook on the back of the hammer and stops its moving forward on the round when all the parts are installed. The gun won't fire until you release the trigger, which resets the hammer to a ready position. Then you can fire it as usual. The design of the trigger, hammer, safety and disconnector is such that it cannot be made to fire full-auto by removing or modifying the semi-auto parts. To sell the gun as a semi-auto, the BATF required these design changes from the original M-16 designs. It must work because millions of them have been sold since they hit the civilian shelves in the middle 1970s. When the disconnector is out, the hammer catches on the underside of the bolt carrier and the bolt won't close. It stops at about halfway closed.

Bartholomew Roberts
June 29, 2007, 04:29 PM
Sorry, my initial closing post was a bit unclear. First, thanks to Onmilo, Gunfixr and others for their comments. I actually appreciate those kinds of posts because they help debunk the myth that semi-auto rifles are readily and easily convertable to full-auto. In addition, they are informative and describe how the rifle works, which we all need to know especially since some popular "conversion" techniques can be dangerous and unsafe.

Stuff like describing using pistol primers to "help" the rifle slamfire makes me nervous because I'd rather not see "The disabled man was attempting to fire the rifle fully automatic using instructions from a website" in some local paper and I worry we sometimes get readers who aren't bright enough to make good risk/reward analysis on that type of decision; but that wasn't the problem.

Now people who ask those kinds of questions - especially when they try to be sly enough to indicate they know they are doing something illegal, those people are very likely to be banned. Discussing things that can be construed as illegal on THR is bad news for everyone - it is bad news for people who cannot visit here if the server is seized in a criminal investigation. It is bad news for those people who have their personal info turned over to a criminal investigation. If you wouldn't ask the question at a gun show where a guy wearing a big ATF jacket was standing next to you, don't ask it here - because I guarantee you that even though you can't see him, he IS standing there.

June 29, 2007, 06:53 PM
If you wouldn't ask the question at a gun show where a guy wearing a big ATF jacket was standing next to you, don't ask it here - because I guarantee you that even though you can't see him, he IS standing there.I'm actually kind of curious; what WOULD happen if you asked these goofy questions to an ATF agent? Not in the interest of turning a rifle into a FA weapon, but just for the sake of knowing what the legal ramifications would be?

Or is that question in itself incredibly idiotic? (and before anyone "suspects" me, I don't plan on doing anything stupid, and don't have an AR to boot).

June 29, 2007, 07:09 PM
They would have to check with 9 other ATF agents and form a study group for 6 weeks and than you would have your answer, total cost to the tax payers would be about $100,000.00 dollars to form the study group to come up with answer, please save my tax money and don't ask them.

June 29, 2007, 07:20 PM
My dear Simmonsguns, you are laboring under the impression that the money for such a study has not ALREADY been allocated, simply awaiting the proper question to be asked! In fact, the money is there and waiting, and MUST be spent by the end of their fiscal year, or they risk having those funds stripped from NEXT years budget. :banghead: THAT is how modern government works. :fire:

Bartholomew Roberts
June 29, 2007, 07:28 PM
I'm actually kind of curious; what WOULD happen if you asked these goofy questions to an ATF agent?

Based on my conversations with ATF, you'd get the wrong answer or at least one that the next ATF agent you asked would contradict. You would have to ask for a written reply before you start the process simmonsguns talks about.

June 30, 2007, 12:33 AM
It's interesting that the AR locks up when fired without the disconnector.

On the FN FAL, the semi versions have been redesigned with the "safety sear" omitted. Often semi-auto FAL's will still have a "Auto" setting marked on the lower receiver and the selector *will* move to the "Auto" setting.

Of course, almost everyone with such a rifle will eventually attempt to fire with the selector set on "Auto," "just to see what happens."

What happens is slightly different then what happens with the AR: The rifle fires a single shot and then the hammer follows the bolt home. The good news is the rifle isn't locked up and the shooter can work the charging handle to recock the action to try to shoot again with the selector set on "Stupid" (Auto) or they can be smart and move the selector back to "Semi" before chambering and firing another round.

Personall, my FN FAL was built so the selector will not move to "Auto" and the "Auto" marking has been obscured. I prefer that as it raises fewer questions if an over-eager LEO ever has a reason to look at my rifle.

July 1, 2007, 04:42 PM
Earlier AR rifles would close all the way, later ones hang up, but the hammer has been changed some, and the reason for it may be right here. When building a 922 compliant FAL, the selector is not supposed to go to the "Auto" position. While the safety selector is not on the 922 parts compliance list, it is required to change or modify so as not to be able to move the selector to auto, and the hammers that are US produced typically don't have the auto sear ledge. When I was building them, I would remove the auto sear ledge from any hammer in the rifle, as to prevent further alterations later, and someone telling the Feds "I got from him that way".

July 2, 2007, 05:03 AM
I knew that the FA M-16 fire control group requires a different bolt carrier to actuate the auto-sear when the bolt finishes closing.

However, I always thought that removing the disconnector on the AR-15 would result in firing out of battery (i.e. Kaboom!) instead of rattling off a full magazine. That and a trip to Hotel Fed were why I told people why it is not good to convert semi to full.

So it's kind of funny to find out that playing Dr Full-Auto with the disconnector results in a very high maintenance single shot instead of a machine gun or a bomb.

July 6, 2007, 10:29 AM
i have never understood peoples need to convert there semi-auto to full-auto, shooting a full-auto weapon calls alot of attention to you no matter where you fire it, and i for one would not enjoy a lengthy vacation in a federal prison

Carl N. Brown
July 6, 2007, 10:58 AM
Folks get curious and think they won't get caught.
The least that you do with one of these "kitchen table"
conversions is convert a legal, reliable military replica
into an illegal, unreliable jail bait, and have to get it fixed.
The worst is, you have a shell fire with the bolt not in
battery or you get caught with an illegal full-auto conversion.
Its like drag racing, illegal and stupid appeals to some people.
The lucky learn better before any harm is done.
The smart know better than to try in the first place.

July 6, 2007, 11:58 AM
I found this video very informative. It shows the action of an M-16 in semi-auto and in full auto. Simply disabling the disconnector will not work, you also have to have the auto sear to keep the hammer from following the bolt.

October 3, 2010, 02:03 PM
First post. Sorry if this question is stupid. Is there really any real tactical use of having a fully automatic rifle for defense purposes?

October 3, 2010, 02:28 PM
welcome to THR, desidius

that's not a stupid question at all, but it would be better to start a new thread (in the tactics and strategy forum) to discuss it, as this thread is really more about the mechanics of the AR fire control group

October 3, 2010, 09:58 PM
Which brings up the shape of the hammer. Having used and cleaned my share of full auto M16's, burst M16A2's, and now having assembled a AR 15 lower, there are some significant differences.

In the day, when Colt started making changes to keep an administration off it's back during the ramp up to the AWB, they changed the hammer from a full length rounded government issue version, to the step cut style.

The full auto tail has always been cut away for semi auto versions, which had been sufficient. Then Colt notched the top, and also cut away the bolt, then made the firing pin collar larger. What I've heard is if the disconnector failed the hammer would follow the bolt and then jam the notch on the back of the firing pin with the chamber locked. It won't go back, it can't separate easily, and the hammer pin has to be removed to help remedy it. Is that correct?

Since M16 bolt carriers are not illegal to use, and the round top hammer isn't either, those parts are included in serious self defense firearms to prevent a catastrophic lock up - which probability indicates almost never happens.

Just as well those AR semi auto parts are out there, gunsmiths can make a good living on it.

October 3, 2010, 10:39 PM
Tirod, on the two occasions where my disconnector wore out enough to allow the hammer to follow, the notch caught on the firing pin before it went into battery. nothing prevented me from using the CH to pull it back. It wasn't stuck and required no special gunsmithing skills beyond recognizing a worn out disconnector and swapping it out. (i usually keep several spares of all the FCG parts in my range bag.)

this animation may be helpful

what i'm struggling to figure out is onmillo's claim that the AR will lock up and require a gunsmith to fix if fired w/o a disconnector. maybe i'm just dense, or onmillo's customers had a different set of parts, but it doesn't make any sense to me.

if you had a notched hammer and unshrouded carrier, it won't even go into battery.
if you have a shrouded carrier, it will go into battery and the hammer will follow it. that will put it in basically the same position as if it were dry fired, only, with a live round in the chamber. but that round isn't locking it up. so what is?

October 4, 2010, 09:18 AM
Run the link with the relevant parts "invisible," and you can visualize how the following hammer could snag the firing pin collar.

Whether it does jam or not depends on the selection of parts, I guess. Colt is reputed to have made sure it will with their parts. If others haven't, no harm no foul.

Frankly, a double or other malfunction could happen from a blown primer or debris in the assembly. It took Colt a lot of work to make a worn out disconnector a show stopper. It makes as much sense as the Qwerty keyboard - put them in the worst positions to slow down the action.

It does raise the question, since a locked up gun will be an generous revenue source to a gunsmith, why the attitude? Jacked up guns are really a 'smiths stock in trade. The interesting custom work doesn't walk in the door everyday, but Joe Sixpack and his truck gun that needs a bit of work are dirt common.

As has been said long ago, "they will always be with us." I suspect an emergency room doctor would be equally justified seeing the stupidity that bring patients in to his care. Nonetheless, the ones that set my bones seemed to genuinely care. They should for $26,000.

Smile and bill accordingly!

October 4, 2010, 08:09 PM
As far as tactical use, a full auto is difficult to control and is generally used for mass fire or surpressive fire. We were trained to fire short bursts only in combat. my opinion is that
full auto is only really usefull in a heavy machine gun in a supported position. Unless you are alone and surrounded. But if you are in an ambush, full auto feels a whole lot better.
Other than it's fun, and I support the right to throw your money away, I can't think of a civilian use for full auto or other uncontrolled shooting.

October 4, 2010, 08:25 PM
tirod, the hammer definitely will snag the collar. but it doesn't jam it. it just stops forward travel so the bolt doesn't go into battery. When you pull the CH, nothing other than the hammer spring is holding it forward, which is not different than pulling the CH after you dry fire.

Carl N. Brown
October 14, 2010, 11:02 AM
The hang-up described appears to be that, without the semi-auto disconnect working, the hammer following the underside of the bolt carrier will hang on the bolt carrier, blocking the bolt partially open and preventing retraction with the charging handle.

After reading these questions, I made the point of inspecting two ARs built recently from new lowers plus commercial triggers (one non-adjustable and one with adjustable trigger). Obviously NOT specifically Colt AR15s but AR pattern semi-auto rifles.

I had been asked this week to debug one of the rifles. The assembler had just pinned the adjustable trigger in the frame like he had done with the non-adjustable, thinking he could adjust over-travel, sear engagement, and disconnect engagement at the range (NOT a good idea). The disconnect was not catching the hammer and the hammer was just following the bolt carrier closed, leaving a barely visible dimple on the cartridge primer. Actually the dimple was about what I see from just the inertia of a free floating firing pin. No disconnect engagement meant bang! once, manually eject second unfired cartridge, not full auto. (Taking the time at the kitchen table with the lower and following the instructions that came with the adjustable trigger had everything working as it should).

Looking at the AR M4gery carbine with the non-adjustable trigger group and the large AR benchrest type rifle with the adjustable trigger group, I did not see any way the hammer could hang underside of the bolt carrier. Again, these were not Colt AR15s but AR pattern rifles.

With this adjustable trigger, with the hammer down, the hammer cannot be cocked when the safety is on: if the hammer is down, it will only cock if the safety is off. If the gun is dry-fired or has a dud cartridge, you cannot fully retract the bolt if the safety was placed on with the hammer in the down position. Other than that, I do not see how these two AR rifles could hang-up as described .

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