Can an AR15 start firing 3 round burst "accidentally"

[Walkalong]

A buddy had a Colt .380 go full auto on him at the range. He came to work all wild eyed telling me about it.

The fellow who sold it to him said it had a "trigger job".

I ordered and installed a new sear and new sear spring for him and it fires properly now. Trigger pull is just as good too. Go figure.

Moral of the story? Leave trigger groups alone.

 

[awgrizzly]

awgrizzly: My "gun guru" (former coworker who set some records with ARs) told me that the original "Green Box" ARs attract lots of extra attention, because of what you guys describe.

Oh yeah... and it's actually comical the lengths that Colt went through to make the SP-1 tamper proof. I have a book that describes it... fun reading. They changed the hammer and trigger pin sizes so M16 parts wouldn't fit (silly rabbit... folks gots drills). The fallout from that mess they created haunts us to this day. They installed a block in the rear of the lower so a auto-sear couldn't be installed, and when folks started removing the blocks Colt stopped fully machining out the cavity in the back of the receiver (but I guess machining aluminum ain't that hard to do). They removed the lower rear portion of the bolt carrier so it wouldn't work with an auto-sear. That's why you can now buy high or low mass bolt carriers... high mass means M16. They cut a bevel out of the carrier just below the rear of the firing pin so the hammer would snag it and jam on auto fire. Colt went way further than they had to under ATF regulations to stop people from turning their ARs into M16s. There were all sorts of tricks being used (still are I believe) and the green label days were the hay day of it all.

A while back I got an '80 vintage SP-1 A1 at a good price. Fiddling around with it one night I noticed something strange with the safety lever... it kind of looked like someone had installed it upside down. Then I realized it could rotate two clicks counter clockwise (DUH). It had the original Colt AR bolt carrier and no auto-sear, but I had to replace all the rest of the M16 fire control parts with standard AR. That's when I learn how that stuff works.

 

[madcratebuilder]

A buddy had a Colt .380 go full auto on him at the range. He came to work all wild eyed telling me about it.

The fellow who sold it to him said it had a "trigger job".

I ordered and installed a new sear and new sear spring for him and it fires properly now. Trigger pull is just as good too. Go figure.

Moral of the story? Leave trigger groups alone.

The real moral of the story is KNOW what you are doing when you work with the FCG.

 

[Caliper_Mi]

The real moral of the story is KNOW what you are doing when you work with the FCG.

AND test afterwards, no matter your skill level!

Load one round then remove the mag so the bolt doesn't lock back, fire - keep the trigger back. Slowly ease off the trigger and make sure the disconnector catches the hammer. Then dry fire and check that the hammer falls to be double sure.

Next load two. Fire one, and check that only one round went down range.

This is probably good practice when buying used guns with "trigger jobs" as well!

 

[HoosierQ]

^^^^This

This is exactly what I did with my new-to-me SKS. The way the firing pin channel is, they are prone to slam fires...stuck firing pin acting like an open bolt gun...more or less.

Loaded two. Fired one, then one. Repeated over and over until I was comfortable that it would not stick...and it never did.

 

[Gun Geezer]

I havw no idea about an AR doing such. But I did have a Remington Model 552 that decided to go full auto. I would usually jam on the 6th or 7th shot.

Lots of fun until I finally got it fixed!

That was about 35 years ago. Folks at that time did not much care. Now days, it could get you in trouble.

 

[303tom]

Never had an AR do it, but I have had my MAS rattle off 2,3,4 rounds before, depends on the ammo I am using...............

 

[jerkface11]

It's possible to bump fire from the bench with a light enough trigger as well. If you don't follow through on your trigger pulls.

 

[FIVETWOSEVEN]

I saw one AR at the range that was a brand new SIG M400. The trigger pins kept walking out and it would double often. I was surprised to see a new SIG doing that.

 

[baylorattorney]

It's no accident if somebody had to pull the trigger that gave a 3 round burst do whatever mechanics malfunction. It has happened tho.

 

[Firewire]

Have seen a new rifle out of the box within 100 rounds start 2 and 3 popping. New trigger assembly was installed and problem went away.

Old thread I know, I saw a guy at the range just put about 200 rounds through a new rifle and the last 50 started doing 2-3 round bursts sporadically. Freaked him plumb out since it is a new gun. He said he'd be sending it back in. I guess the warmth or dirtiness started it?

 

[1911 guy]

I saw a rifle double with every pull of the trigger at a range once. The owner would look at it confused, shoot again with the same result. I offered to look at the rifle and saw the hammer spring was in backward/upside down, whatever you want to call improper orientation.

Quote:
The fire control group of the AR is so well known there's not much reason to not talk about it. Rather, maybe it should be talked about in order for folks to avoid trouble.

I agree. There's schematics, specs, and all sorts of useful information. Unfortunately, there's also even more myth and misinformation. The more "straight poop" available, the better.

 

[JohnKSa]

A semi-auto gun could go full-auto if it were worn or damaged. Some designs might start doubling consistently due to wear or damage. An inconsistent number of rounds fired per trigger pull is a possible outcome of wear or damage.

Consistent 3 round bursts are not a likely malfunction for a worn/damaged semi-auto.

 

[AK103K]

Ive had consistent 3 and 4 round bursts out of my one Armalite with reloads using Winchester primers. This was back during the last panic, when the CCI's I normally use werent available.

After the first couple of bursts, I switched to some GI ammo I had along, and the gun worked fine (and has been fine ever since), so Im pretty sure it was the Winchester primed reloads and the gun was probably slam firing.

 

[tark]

When I lived in California I shot at a range where you never knew if the guy beside you was a banker of an ATF agent. The range had a very strict policy: No rapid fire and certainly no automatic fire. That guy at the range was DAMNED lucky that wasn't the situation at the range you were at. Two three round bursts consecutively discharged would have drawn immediate attention from any cops.

I am new to modern ARs. I did own a colt H-BAR 30 years ago. I don't know enough about them to offer a constructive evaluation, but I know this: I doubt very much that one would be able to fire three round bursts without some deliberately illegal modifications.

 

[j1]

J1

Soitanly it can.

 

[BudgetBucks1]

I know it isn't the same gun but I witnessed a friend's AK fire bursts from 2 rounds to 5 rounds kind of randomly. I took it apart and cleaned the gas port and it worked fine after that. I asked if he had ever cleaned it and he said that he had not and had fired over 5,000 rounds through it of dirty russsian ammo. I guess the bolt went back far enough to chamber a round but not far enough to lock the hammer back.

 

[Tirod]

Sure - and have a perfectly good trigger.

It's called bumpfire.

Hold it loosely enough the bolt chambering carries the gun forward against a light target trigger with little travel and it goes off again, and again. Some can get a 6 pound issue trigger to do it.

That range officer may need to get used to the effect of the new triggers which fire on pull, then on release. It's an older competition shotgun type of trigger now being sold for AR owners who don't prize accuracy over volume of fire.

 

[WardenWolf]

Sure - and have a perfectly good trigger.

It's called bumpfire.

Hold it loosely enough the bolt chambering carries the gun forward against a light target trigger with little travel and it goes off again, and again. Some can get a 6 pound issue trigger to do it.

That range officer may need to get used to the effect of the new triggers which fire on pull, then on release. It's an older competition shotgun type of trigger now being sold for AR owners who don't prize accuracy over volume of fire.

If ranges are smart, they won't "get used to" that trigger and simply ban it instead. It's an unsafe modification, no matter how you look at it. They're also a legal minefield, as I mentioned HERE.

Anyway, I've heard of AR trigger groups doing this if they're sufficiently worn or improperly modified. The guy who was sent to prison over it knew about the problem with his gun but, instead of fixing it, kept it that way as a "feature". He was far from innocent.

 

[trentcwwilson]

If ranges are smart, they won't "get used to" that trigger and simply ban it instead. It's an unsafe modification, no matter how you look at it. They're also a legal minefield, as I mentioned HERE.

Anyway, I've heard of AR trigger groups doing this if they're sufficiently worn or improperly modified. The guy who was sent to prison over it knew about the problem with his gun but, instead of fixing it, kept it that way as a "feature". He was far from innocent.

Ah, the famous dead man trigger. Never seen one that fires on pull though, sounds like one that fires on pull and release would be stepping of BATFE toes. But they are dangerous. Our local club just banned then because an old man shot himself in the foot on the trap field. Had one because he had trigger pull issues.

 

[ljnowell]

Ah, the famous dead man trigger. Never seen one that fires on pull though, sounds like one that fires on pull and release would be stepping of BATFE toes. But they are dangerous. Our local club just banned then because an old man shot himself in the foot on the trap field. Had one because he had trigger pull issues.

The old trap shooters used a trigger called a release trigger, and it was just that. It didn't fire on pull, only on release.

 

[trentcwwilson]

The old trap shooters used a trigger called a release trigger, and it was just that. It didn't fire on pull, only on release.

That's the dead man trigger. Many a holes blasted into the ground because of them. The other part of my comment was about another post. Never seen a trigger shoot of pull and release, only one or the other.

 

[ljnowell]

That's the dead man trigger. Many a holes blasted into the ground because of them. The other part of my comment was about another post. Never seen a trigger shoot of pull and release, only one or the other.

I've ran in trap circles my whole life and the only thing I've ever heard it called was a release trigger, never a dead mans trigger.

 

[trentcwwilson]

I've ran in trap circles my whole life and the only thing I've ever heard it called was a release trigger, never a dead mans trigger.

What part of the country you live in? Call it soda or pop?

 

[M1key]

223 reloaded with pistol primers, CMMG bargain bin AR...(wasn't me)

M