AR not pulling shot cases out of barrel

[stagpanther]

If those pictures show what looks like groove cut into the front of the bolt lugs, I'm never seen that before. It would seem something inside the bolt extension is cutting the front of the lugs. I've seen plenty of bolts with broken lugs, chips and etc. But not grooves. And thats not normal. I would not fire that AR again. I would take that AR to a gunsmith that's familiar with ARs.

look at the long wedge of the bolt rim worn away that I circled--then look at the radiused edge on the chamber face where there appears to be an uneven erosion--that's why I think something is causing an out-of true lock-up when the cartridge goes into battery. Could be wrong though.

[MagnoliaHunter]

There are no grooves cut into the lugs. the shiney sections that you have cirled are perfectly flat as are all of the lugs. There has been some wear to take the finish off but when I drag my fingernail across the lugs you can not feel anything. All of the lugs faces are flat. Here is a better picture. I took the pictures with my camera. I can't get a good angle on the chamber face to show it, but there appears to be even wear even though it doesnt look like it in the pictures that i posted earlier. It must be the angles and the flash. Here is a new picture of the bolt that i just took.



After going over my shooting notes again, I was wrong. I was looking at the wrong dates when trying to see what day it was jamming. When it was jamming, it was with different ammo. Let's just say theoretically, is military ammo loaded hotter than the factory ammo that i am using now? Would that cause it to not eject but the factory ammo would eject? The factory ammo that I shot last weekend that worked flawlessly was Winchester 55 Grain Pointed Soft Point.

In any case, I found a local gun shop that several people with ARs have recommended. I will have them check out headspacing, barrel alignment and possible wear. I will also have them check/replace the extractor and extractor spring.

[Bartholomew Roberts]

A 20yr old Sendra? The gas port is larger than 0.062" and it is overgassed, as mentioned earlier. The increased finish wear is because it is trying to unlock with a higher residual pressure. Upgrade your ancient extractor spring and go to at least an H-buffer. That should fix your problem for under $40.

Let's just say theoretically, is military ammo loaded hotter than the factory ammo that i am using now?

Any military ammo is going to be loaded hotter than .223 55gr SP SAAMI ammo.

FYI: Sendra is one of the original AR15 kit builder companies begat by the Drasen family. Spin offs include Nesard, Model One, M&A Parts, etc. They go way, way back.

[ed308]

That's good to know. If you round off edges of the extractor pin, that can help with extraction as well. You can use a Dremel tool:

http://accurateshooter.net/Blog/whitjamfix02.jpg

[Mobuck]

" Let's just say theoretically, is military ammo loaded hotter than the factory ammo "

"Any military ammo is going to be loaded hotter than .223 55gr SP SAAMI ammo."

The question is, was this ACTUALLY "military ammo" or "military TYPE ammo"?

[MagnoliaHunter]

I'm a computer engineer. I'm smart enough to know that I know nothing about working on guns. I'm not taking a dremel tool to any internal parts. I will take it to the local guy here that everyone says does great work.


Mobuck, I will take your answer to mean its safe to say that my ammo that jammed was hotter than the ammo that didn't.

Thanks for all of the help. I am going to try to get to the gun shop in the next couple of days. I will keep you guys updated.

[Bartholomew Roberts]

Replacing the buffer or the extractor spring is very simple. You can definitely DIY. Heck, you are only one step away from the buffer in your pics and maybe 3-4 steps from the extractor spring. I'd try going to an H-buffer and an upgraded carbine extractor spring and insert first before sending it out for professional help.

The extractor spring will be a helpful upgrade regardless and costs less than a good cheeseburger.

[ed308]

It ain't rocket science LOL. I got a degree from the Univ of Tennessee and even I can do it. And the pen is cheap if you screw it up!

http://accurateshooter.net/Blog/whitjamfix03.jpg

[Shenna9220]

The second I started reading this thread my brain was screaming headspace, once the op said the barrel had been replaced I fully believe it should be checked before firing another round.

[Bartholomew Roberts]

Headspace on ARs is set when the barrel extension is pinned on. So assuming it is done properly, the only way to get improper headspace by swapping a barrel would be an extreme tolerance stacking between a used bolt and used barrel. This seems unlikely in a rifle with less than 500 rounds.

Not to mention the rifle is showing all the classic signs of being overgassed and is from an era and manufacturer where that was a fairly common issue.

[Mobuck]

"headspace is set when the barrel extension is pinned on"
Guess I'd better re-check my barrel extension installation procedure.

[marine6680]

This is a fixed stock type rifle correct?

If so, getting a heavier buffer is more difficult... You may need to replace the buffer weights in the one you have.

Are the weights the same dimensions in a rifle buffer as they are in a carbine buffer?

[Bartholomew Roberts]

Originally Posted by Mobuck

Guess I'd better re-check my barrel extension installation procedure.

Well, if we're being all precise, the extension is threaded on and the last step is putting the alignment pin in place. Thus the pinning. I just repeat what I'm told. If you can't teach a monkey to do it in one go, it is beyond my mechanical skills.

Originally Posted by marine6680

If so, getting a heavier buffer is more difficult... You may need to replace the buffer weights in the one you have.

If it is a 20 year old Sendra lower, it probably needs a new action spring. If there is still an issue, then it is probably less a question of a heavier buffer and more a "Where did the cutrate, sketchy buffer in this rifle come from?" In the pre-2000 era, there were some, uh... innovative approaches to reducing manufacturer costs and Sendra/Nesard broke a lot of ground there.

[stagpanther]

Extensions are like bolts--usually subbed out to just a few manufacturers for cost reasons, and like bolts even if within tolerances, slight alignment issues can cause headaches in cycling/firing. I agree that given the barrel was replaced, the probability goes up that the problem is related to the barrel install.

[ed308]

Hey MagnoliaHunter, did you find out what the problem was with your AR?

[MagnoliaHunter]

No. Everybody in the house got the flu and strep throat right after my last post. You should try both of them together, it's awesome. I am going to try to get to the gun shop in the next week.

[BWM]

IF it shoot good in the cooler weather then does not shoot good in hot you need to make shore that you ammo is not in the sun or a place that it can get hot.