AR help please!

[Guitarmoto]

See post #10 before commenting on legality etc... only looking for help with bolt issue and runaway firing... I appreciate any input or suggestions for friends rifle.

Brand new ar put together and on the first time taking it out it would run off with 3 round bursts every time. What could cause this?
He tried to address it couple times to no avail.
He ran it that way for the day planning on addressing the issues with it later when we ran into second problem.

The gun would fire but would not cycle. Did not seen to be the gas system. Gas was getting through just fine and gas block was solid. Not a lot of fouling.
When charging a round, it would chamber just fine and I could keep pulling the charging handle and eject through whole mag smoothly.
As soon as fire the chambered round the bolt would not blow back. It was basically stuck in place.

After the round was fired I would pull the charging handle and it took fair amount of effort to get it out of battery and eject the spent cartridge.
Only happened after round was fired.

What gives? Any thoughts?
I appreciate any help...

**shooting 556

[Riceball]

I'm no expert but it sounds to me like you're gas system isn't sending enough gas back to work the action properly. I had something similar happen back when I going through MCT but that was with blanks but it sounds very similar, I'd fire a blank, it would cycle the action but wouldn't eject the spent casing, I'd pull the trigger and it would click on the empty casing, then I'd have to pull the charging handle again in order to eject the old casing and chamber a new round. I don't remember if anything was done to fix it, all I remember was that ultimately it resulted in a stove piped casing and it had to be cleared with a cleaning rod.

So I'd look at your gas system, what kind of gas block, what kind of gas tube, and what kind of barrel making sure that they're all the same type ie. all carbine, or all mid-length. If that's all good then I'd make sure that everything is put together correctly and there's no leaks and everything is on nice and tight.

[Noggles]

You stupidly screwed it up by feloniously firing it full auto... Most likely out of battery, thus screwing up either the bolt or chamber lugs... Check out the bolt for undue wear.

[bryant]

ammo type used?

[motox917]

Make sure your disconnector spring is in place. A buddy of mine lost his and put the gun back together without knowing it was missing and he got the same result

[Munny$hot]

Make sure your disconnector spring is in place. A buddy of mine lost his and put the gun back together without knowing it was missing and he got the same result

or possibly upside down (small end needs to be pointing upward)

[gemini1]

OP, you're lucky there's no MIB roaming around looking for people like you. Seriously, you should address issues on burst firing the first time it occurred.

Check and make sure you're disconnector spring is in its correct position, wider end should be into the trigger assembly.

What ammo were you using?

[Guitarmoto]

Not my rifle, buddies. I'll have him check disconnector spring.... i broke his rifle down coupke times snd didnt notice anything out of place that was apparant.
The burst shots were antecedant to stuck bolt and cycling problem so Im sure his bolt got jacked up in some fashion.

I cant figure how though unless a round went off out of battery. Ive shot rapid fire ARs much faster than his rifle was doing. He only shot maybe 100rnd
Federal .556 ball ammo....

[JDay]

Brand new ar put ogether and on the first time taking it out it would run off with 3 round bursts every time. What could cause this?

We ran it that way for the day planning on addressing the issues with it later when we ran into second problem.

Good way to wind up in jail for manufacturing a machine gun. You need to stop firing the second you discover an issue like that and figure out what is wrong. The ATF doesn't care if it wasn't intentional.

[Guitarmoto]

Agreed on all suggestions of ceasing fire immediately due to firing capacity but I cant make someone heed my suggestions. His decision to shoot his rifle in that state and now this is where he's at.

Just trying to help him get his rifle back operating smoothly and legally

[pardou]

Agreed on all suggestions of ceasing fire immediately due to firing capacity but I cant make someone heed my suggestions. His decision to shoot his rifle in that state and now this is where he's at.

Just trying to help him get his rifle back operating smoothly and legally

come on guys, give this guy a break. In the begining of the thread the OP said "nevermind the legalaties..." it isnt even his rifle ... Just trying to fix it for a friend.

[Mickael81]

On my first build i forgot to put a little sping that goes in under the trigger sear. The rifle did not cycle properly. The trigger kept on failing to reset after every shot and on a few occations it bump fired.