Help me sort out this AR mystery.

[robinsre]

So my beloved AR, the rifle which is my "go to gun" in case of emergency, has been relegated to the back seat by my trusty .30-30 for reliability issues. It's giving me grief and I can't find out why.

Here's the down-low.

The gun is chambered in 5.56. I've been shooting 5.56 through it.

Last trip to the range two magazines had issues where the gun did not properly cycle all the way, and the bolt locked into the star chamber. This required me to "slam" the muzzle onto a hard surface until the carrier slid far enough forward I could remove the upper from the lower.

Once removed I pushed the carrier further forward and the rifle continued working.

This I chalked up to bad ammo failing to cycle the gun properly, I set aside that ammunition and things started to work well again.

Thats when the real issue started happening. I started having FTE (extracts). What APPEARS to be happening is that in about 1 in 25 rounds the extractor rips the case lip off of the cartridge and it correspondingly jams in the chamber. It's stuck in there good too. Twice I had to pound it out with a cleaning rod.

I'm assuming the issue is either A) gun's chamber was boogered up by the last smith that worked on it or B) This ammunition is bad, the brass is weak, resulting in overexpansion of the brass in the chamber and my extractor ripping the case lip off.

The brass does not appear to have any abnormal marks or dings on it when it is removed. It does however appear to be slightly bulged where the case starts to neck down.

I'm reluctant to say that it's only the ammo, because others have used this same batch from the same manufacturer without incident.

Any ideas/suggestions?

- Ryan

[Mercmar]

Two suggestions: (1) Get somebody who knows at least SOMETHING about ARs to help you, the next time you have a problem and/or (2) get somebody who knows at least SOMETHING about ARs to help you, the next time you have a problem.

If the above recommendations don't produce satisfactory results, then secure the services of a competent gunsmith, before you really screw something up!

[robinsre]

Originally Posted by Mercmar

Two suggestions: (1) Get somebody who knows at least SOMETHING about ARs to help you, the next time you have a problem and/or (2) get somebody who knows at least SOMETHING about ARs to help you, the next time you have a problem.

If the above recommendations don't produce satisfactory results, then secure the services of a competent gunsmith, before you really screw something up!

Thanks!

You've been a great help!

It seems I've taken your advice EVEN BEFORE YOU CHIMED IN.

That's why I'm posting here.

Sheesh, some folks just want to criticize and don't really want to offer any decent advice.

- Ryan

[PackerfanXD]

Subscribing, with little to offer.

[f0cker]

Originally Posted by robinsre

So my beloved AR, the rifle which is my "go to gun" in case of emergency, has been relegated to the back seat by my trusty .30-30 for reliability issues. It's giving me grief and I can't find out why.

Here's the down-low.

The gun is chambered in 5.56. I've been shooting 5.56 through it.

Last trip to the range two magazines had issues where the gun did not properly cycle all the way, and the bolt locked into the star chamber. This required me to "slam" the muzzle onto a hard surface until the carrier slid far enough forward I could remove the upper from the lower.

Once removed I pushed the carrier further forward and the rifle continued working.

This I chalked up to bad ammo failing to cycle the gun properly, I set aside that ammunition and things started to work well again.

Thats when the real issue started happening. I started having FTE (extracts). What APPEARS to be happening is that in about 1 in 25 rounds the extractor rips the case lip off of the cartridge and it correspondingly jams in the chamber. It's stuck in there good too. Twice I had to pound it out with a cleaning rod.

I'm assuming the issue is either A) gun's chamber was boogered up by the last smith that worked on it or B) This ammunition is bad, the brass is weak, resulting in overexpansion of the brass in the chamber and my extractor ripping the case lip off.

The brass does not appear to have any abnormal marks or dings on it when it is removed. It does however appear to be slightly bulged where the case starts to neck down.

I'm reluctant to say that it's only the ammo, because others have used this same batch from the same manufacturer without incident.

Any ideas/suggestions?

- Ryan

First issue...Why beat the muzzle on the ground? Use the Forward Assist, it is there to help get the bolt and carrier into battery. As to why it is doing that, it could be a few things. Check to make sure the chamber and barrel extension are really clean, and that there is enough lube. Also, would the BCG come back if you racked the charging handle? If so, drop the magazine next time, rack the CH, remove the round that is there and inspect the chamber/barrel extension/upper receiver as a whole.

Ripping the edge of the case off IIRC is a sign that your extractor spring is too strong. From what I remember, cutting ONE coil off the spring will fix it. I'd double check that with a few searches. Try shooting some different ammo also, as it might be weak brass like you said.

Pick up a few boxes of new ammo before you shoot next time, and alternate between that ammo and the stuff that gave you problems. See if it is ammo related or if it is the rifle itself.

[f0cker]

After re-reading your post...you said that two magazines had issues. Were you using only those two mags or were there others? If only those to mags had issues with chambering a round, it might mean that the magazine springs are weak and aren't pushing the round up enough for it to be stripped by the BCG. Mark those two mags and keep an eye on them next time you shoot.

[robinsre]

Originally Posted by f0cker

First issue...Why beat the muzzle on the ground? Use the Forward Assist, it is there to help get the bolt and carrier into battery. As to why it is doing that, it could be a few things. Check to make sure the chamber and barrel extension are really clean, and that there is enough lube. Also, would the BCG come back if you racked the charging handle? If so, drop the magazine next time, rack the CH, remove the round that is there and inspect the chamber/barrel extension/upper receiver as a whole.

Ripping the edge of the case off IIRC is a sign that your extractor spring is too strong. From what I remember, cutting ONE coil off the spring will fix it. I'd double check that with a few searches. Try shooting some different ammo also, as it might be weak brass like you said.

Pick up a few boxes of new ammo before you shoot next time, and alternate between that ammo and the stuff that gave you problems. See if it is ammo related or if it is the rifle itself.

Tried both the charging handle and the forward assist first, neither worked. The charging handle wouldn't work because the prongs on the bolt had rotated inside and locked inside the chamber, I have no idea why the forward assist wasn't doing what I wanted it to do. In the end the only way to get the carrier to come forward was to "tap" (I shouldn't have said slam) the muzze down on a solid surface.

[robinsre]

Originally Posted by f0cker

After re-reading your post...you said that two magazines had issues. Were you using only those two mags or were there others? If only those to mags had issues with chambering a round, it might mean that the magazine springs are weak and aren't pushing the round up enough for it to be stripped by the BCG. Mark those two mags and keep an eye on them next time you shoot.

Those were the only two magazines I had at the time. Will be bringing more out with me next weekend.

[f0cker]

Interesting. The FA should have worked. Have you ever shot ammo like Wolf or Monarch laquer coated stuff through the gun? As it heats up, that laquer melts and can harden in the chamber and barrel extension. Over time, it can build up and cause jams like you're having. Clean the everliving **** out of that part of the upper and see if it helps. What was the ammo, BTW?

[CLAYBROOK]

I'd post this question on ar15.com. Someone there will be able to help.