Problems with ar 15

[Somuchguns]

Hi guys, i built my first custom ar 15 with different brand name parts. But i been having issues with the rifle double feedings, failure to eject and bolt not locking up. I been doing researches online and it seems culprit might be the buffer springs. Can anyone confirm my suspicions. Thanks!

[God Bless America]

Hi guys, i built my first custom ar 15 with different brand name parts. But i been having issues with the rifle double feedings, failure to eject and bolt not locking up. I been doing researches online and it seems culprit might be the buffer springs. Can anyone confirm my suspicions. Thanks!

Could be many things. What does it do when you load one round in the mag, chamber that round, and fire that one round?

[NPFreedom]

Could be lots of things.

Do you have another AR or a friend's AR. You can try to narrow it down by swapping one part at a time. Like for example, change the buffer spring. Shoot a few rounds. Then put in your old spring back and change the buffer, then change the BCG, etc.

[nedro]

Double feeding?
Like one in the chamber and one stuck between the BCG and the round in the chamber?
First things first. How did the measuring of the chamber go?
Next, report back on what GBA asked you to do.
Next, List all parts and include the spring and buffer weight.
Then wait for more questions.

[Calico1404]

Too many variables at this time. Eliminate some by answering the questions above

[Somuchguns]

when i pull the charger, the cartridge chambers and ejects normally. but when i start shooting the ar, that's when the problem starts

[twidget1995]

The usual way to test if your AR is working properly is to load one round in the mag, charge the round, aim and fire. The bolt should lock back. If that isn't happening you have a problem.

If that works, the next step is load two rounds and see if it cycles properly by ejecting the first round and loads the second.

There are people trying to help that are much more knowledgeable than me. They've asked some questions that you need to answer.

[etwinam]

Sounds like you have a few problems going on, first is probably to address like stated above if it is a single load problem or multiload problem... I'm assuming your timing is off on the buffer and bcg, poss trigger control group.

[rubbman]

Is it a brand name lower or 80%?

[ar15barrels]

i been having issues with the rifle double feedings, failure to eject and bolt not locking up.
I been doing researches online and it seems culprit might be the buffer springs.
Can anyone confirm my suspicions. Thanks!

Double feeding is not actually possible unless one lip of the magazine is broken or it is caused by operator error.
Double feeding involves TWO LIVE ROUNDS out of the magazine and in the action.
Most people incorrectly call a failure to extract/eject a double feed.
A failure to extract leaves a fired case and a live round in the action.

Go read this:

https://www.ar15barrels.com/prod/operation.shtml

Failure to lockup can be short headspace or faulty ammo that is too long to fit into the chamber if the chamber IS actually within spec.
The buffer springs are rarely a problem.
Failure to lockup can also be bolt bounce when a lower receiver is out of spec and the buffer is not properly contacting the carrier.
That shows up as misfires.

[divingin]

Most people incorrectly call a failure to extract/eject a double feed.
A failure to extract leaves a fired case and a live round in the action.

This.

Sounds like everything the OP said points to the action short stroking, which fails to eject the fired case (the lack of bolt lock-back is kind of a giveaway.) The bolt comes back far enough to strip the next round from the mag, while simultaneously stuffing the fired case back into the chamber. Since the stripped round has nowhere to go, it ends up crammed against the fired case.

If it were me, I'd check/test/investigate for (in order) adequate lubrication/free movement of parts, try different ammunition, amount of gas, then start testing for out of spec parts (the suggestion of swapping parts is easiest unless you want to end up with a bunch of spares.)

[Calico1404]

Double feeding is not actually possible unless one lip of the magazine is broken or it is caused by operator error.
Double feeding involves TWO LIVE ROUNDS out of the magazine and in the action.
Most people incorrectly call a failure to extract/eject a double feed.
A failure to extract leaves a fired case and a live round in the action.

Go read this:

https://www.ar15barrels.com/prod/operation.shtml

Failure to lockup can be short headspace or faulty ammo that is too long to fit into the chamber if the chamber IS actually within spec.
The buffer springs are rarely a problem.
Failure to lockup can also be bolt bounce when a lower receiver is out of spec and the buffer is not properly contacting the carrier.
That shows up as misfires.

^^ Thread done.

[Euphoria526]

Did you drop it on the carpet op?!

[Somuchguns]

i actually dont remember the parts i bought, because it took me a few years to buy them all. but ill hit the range when i have time and try out all the suggestions and get back to you guys. thank you all

[JAE]

Last time I saw this a friend built a 300 AAC (actually her husband built it and he wasn't there). So we went through a lot of stuff and at the end of the day he had stuck a heavy buffer in there thinking it was "the best parts he could buy". Swapped for a standard carbine buffer and solved the problem. Just like that. Flawless afterwards.

Sounds the same take a look at that.