AR Troubleshooting?

[jester]

OK, I've built my OLL and took it out once, but it was doubling(firing 2 shots for one pull of the trigger)
What could be the problem?
Also, when pulling the charging handle, it doesn't immediatly spring back into it's locked position,Just stays out.
Am I missing a spring here or something??
Thanks!

[JHC]

OK, I've built my OLL and took it out once, but it was doubling(firing 2 shots for one pull of the trigger)
What could be the problem?
Also, when pulling the charging handle, it doesn't immediatly spring back into it's locked position,Just stays out.
Am I missing a spring here or something??
Thanks!

Whatever it is you need to fix it ASAP, you don't want to be the next guy to be charged with having a machinegun due to malfunction.

[jester]

Fixed mag(prince)
Empty mag...

you don't want to be the next guy to be charged with having a machinegun due to malfunction.

Damned skippy I don't...

Yes, buffer installed

Do you suggest I strip the lower and start over?

Yeah, after it doubled, I immediatly put away.
This was at Angeles.

[jester]

Empty mag: you have to manually push the charging handle forward into its latched position. There is no spring that will do that for you when the bolt is locked back.

Why? The magazine follower of the empty mag pushes up on the bottom of the bolt catch. The bolt catch in turn holds the bolt carrier group in the open position. Therefore the bolt carrier group can't pull the charging handle forward.

So, if the mag was charged, because the follower was not impeding the bolt,it Would lock back into place??

Sorry, I'm uncomfortable with loading a semi in the house

[Sig357]

So, if the mag was charged, because the follower was not impeding the bolt,it Would lock back into place??

Sorry, I'm uncomfortable with loading a semi in the house

NO...If you have a mag with rounds in it and pull on the charge handle the bolt would slam forward along with the charging handle. If it didn't it wouldn't be a semi auto.


You can test this without a mag inserted in the mag well.

[4D5auto]

If the pin hole is out of spec on the trigger group, your result may happen. It's a shame a malfunction is now illegal!

[supersonic]

Also, I believe this doubling can happen if the disconnect spring is installed upside-down (spring is tapered - one end larger in diameter than the other).

[ty423]

could it have fired more rounds if you held the trigger any longer or did the bolt just catch back right after the second shot?

[ar15barrels]

Also, I believe this doubling can happen if the disconnect spring is installed upside-down (spring is tapered - one end larger in diameter than the other).

That's the most common cause of doubling.
Logic dictates that you put the spring small-end-down into the trigger because it fits nice that way.
Unfortunately, that also lets it get stuck there when the disconnector is called into action.
The stuck spring causes a disconnector malfunction which results in the extra shot being fired.

Correct installation of the disconnector spring is to press the LARGE end down into the trigger until it snaps into place.

[mason1800]

So, if the mag was charged, because the follower was not impeding the bolt,it Would lock back into place??

Sorry, I'm uncomfortable with loading a semi in the house

You should have snap caps for every caliber of fireaarm you own, just for these issues. Always check that, the firearm cycles correctly before going out to shoot. Just a thought.

[ty423]

but snap caps won't eject the round and push the bolt back since there isn't any gas pressure therefor the next round won't chamber. I guess you could kind of simulate it with a couple snap caps by manually pully the charging handle after pulling the trigger.

[supersonic]

That's the most common cause of doubling.
Logic dictates that you put the spring small-end-down into the trigger because it fits nice that way.
Unfortunately, that also lets it get stuck there when the disconnector is called into action.
The stuck spring causes a disconnector malfunction which results in the extra shot being fired.

Correct installation of the disconnector spring is to press the LARGE end down into the trigger until it snaps into place.

- Thanks, Randall! (it might have helped had I also mentioned WHICH way to install it correctly)!!!

[ty423]

There is a procedure called a function check, that allows you to verify the basic operational functions of a rifle without firing a round. If more people were aware of the manual and actually RTFM before going to the range, the question wouldn't come up as often as it does.

http://quarterbore.com/library/pdf_files/tm9-1005-319-23.pdf

http://quarterbore.com/library/pdf_f...005-319-10.pdf

I thought since it was a problem with doubling I don't see how you would check that without having to cycle a round. Then I thought you can dry fire and while still holding the trigger pull the charging handle to simulate a cycle for the next round. Anyways thanks for the link...very helpful

[C.G.]

Once I had doubling, thought it was light primers on Prvi Partizan M193. Nevertheless, took the trigger apart just in case I installed the spring incorrectly. The spring was installed properly, but had 2 pieces of a blown primer fall out of the trigger assembly.

[ar15barrels]

Once I had doubling,
took the trigger apart just in case I installed the spring incorrectly.
The spring was installed properly, but had 2 pieces of a blown primer fall out of the trigger assembly.

+1.
I have had this a couple times.

If you notice this more than once on the same gun, it's probably time for a new firing pin.
What happens when you start popping primers is that the gas erodes the firing pin tip, making it have sharp edges.
The sharp edges cause popped primers on loads that would otherwise have been fine with a properly rounded firing pin tip.
The sharp edges create a self-propogating problem.