AR malfunctioning, need advice

[StoneBear]

Got a late 80's Olympic AR (I know, I know ) that has been sitting for quite a while. I decided I was going to get the thing up and running, its in excellent condition, well maintained, but at the range I get about 15% FTE/FTF. I believe the firearm is short-stroking, but I am not positive. I haven't had an opportunity to give it the single shot/ lock open test.

I have tried a half dozen different good quality ammos, replaced the ejector and extractor springs, gas rings seem to be within spec., gas tube is clear, bolt key seems damage free. I know a mis-aligned gas block can cause such a problem, is this common?

Any (constructive ) ideas are welcome. I'd liked to sell this firearm, but I will not pass something along that is malfunctioning.

Also, its got a flat-top upper on it and I am assuming that was not an option back in the 80's, so it may have been a replacement.

If anyone knows a good Gunsmith for this type of thing, please let me know.

 

[Brunosr]

Have you tried different magazines?

 

[Mike-Mike]

Can u describe the actual failure? there ate many different FTF's . Do you have the right buffer in the stock?

 

[Hanwei]

When you say FTE/FTF, are you getting any light strikes? Or are the fired casings just not ejecting?

If you're getting light strikes, your hammer spring may be installed backwards. If you're getting casings not ejecting or not feeding (short stroking) then I'll leave that to other more knowledgeable people.

 

[drgrant]

Any (constructive ) ideas are welcome. I'd liked to sell this firearm, but I will not pass something along that is malfunctioning.

If this gun has a preban lower on it, the lower is worth more than the whole gun probably was, depending on how much you paid for it. If the lower isn't seriously out of spec, you could probably strip the whole thing into parts and make out OK.

-Mike

 

[gixxer_kid]

Need more info. I would have done a single shot lock test before I started replacing extractor springs and shit. But for now check your gas system and buffer/spring

 

[StoneBear]

Have you tried different magazines?

I have tried 5 or 6 mags, same result.

Can u describe the actual failure? there ate many different FTF's . Do you have the right buffer in the stock?

I am getting a lot of stove pipe type failures, which I see as the most serious issue. The spent shell is getting really pinned up on the ceiling of the receiver, enough to be quite deformed.

Not sure about IDing the buffer spring, that is outside my ring of knowledge. I am assuming I'll have to pull the rear stock. What am I looking for here?

Obviously with the stove pipe the next round will not feed, however, I occasionally get a failure to feed where the spent shell is fully ejected. I attribute this failure to either a short-stroke that just happen to get the spent shell clear or to a faulty magazine, but I honestly cant be sure. The round that fails to feed doesn't seem to be getting any contact with the bolt (no scraps on the the brass) and remains fully seated in the mag. I take the mag in question out of the rotation and it seems to take care of the problem.

When you say FTE/FTF, are you getting any light strikes? Or are the fired casings just not ejecting?

I seem to be getting pretty solid strikes from the firing pin, but I cant be positive, that is another thing I ll have to check. I guess I'll compare the Olympic spent case to one of my Stag's.

If this gun has a preban lower on it, the lower is worth more than the whole gun probably was, depending on how much you paid for it. If the lower isn't seriously out of spec, you could probably strip the whole thing into parts and make out OK.

It is a pre-ban and I have considered this, but its my old man's and he would like to see it running properly before any decision to part with it is made.

Need more info. I would have done a single shot lock test before I started replacing extractor springs and shit. But for now check your gas system and buffer/spring

I would have done that test right off had I known about it. I'm picking this stuff up as I go and in that regard its turned into quite a learning experience, to look at it this headache in a positive light. The single round/lock test is so logical, I am surprised I didn't just think of it.

 

[Mike-Mike]

If you don't have snap caps or dummy rounds.

Go to the range.
Load 5 -10 rounds
cycle the gun by pulling the charging handle hard and fast and let go
do this until the bolt locks back
if they all cycle through no problem I would look at the gas system and the buffer.

Does it cycle by hand nice and smoothly or does it make a scraping noise?

To remove the buffer and spring. just break open the AR by pushing out the rear pin
you will see a little pin in the front-bottom of the stocks tube. If you push it in, the spring and buffer will come out at you.
Did some one change the stock?
Did someone take apart the bolt and put it back together?
Hose down your bolt with CLP or gun oil if it's not wet.

 

[StoneBear]

Does it cycle by hand nice and smoothly or does it make a scraping noise?

I can't be sure not having it here in the office to check, but I don't think it is quite as smooth a cycle as my Stag. If it is scraping, is it the bolt carrier that you'd look at as the culprit?

Did some one change the stock?
Did someone take apart the bolt and put it back together?

This firearm did have a previous owner before my father and I think its pretty clear that they made some modifications. I believe that rifle was manufactured in '88-'89, but it has a collapsible stock and a flat-top upper with picatinny rail. Don't think these particulars were manufactured then.

I dont know if the previous owner worked on the bolt, but I replaced the ejector and extractor spring and spring buffer with ones that were supposed to add increased action. I saw little to no improvements.

Hose down your bolt with CLP or gun oil if it's not wet.

Its been well cleaned and lubed.

 

[StoneBear]

I have no problem getting at the buffer spring, these are simple, but seemingly quirky devices. What is it that I do once I get there? Are there any visual cues if a problem is present? How do I go about solving them.

I'd like to fix this problem myself, but I'd take it to someone with the know-how if it comes to it. I do want to avoid sending it over to Olympic, I spoke with them and it seems to be an indefinite wait.

 

[Fixxah]

Being a novice myself, I have insalled the bolt in the opposite direction. I caught this after dry firing with a snap cap. Not sure if this would stovepipe and crush though.

 

[Blitz1]

You didn't let Nicole shoot it did you? She likes to break AR's.

 

[Fixxah]

yo

 

[Scrivener]

Have you taken the handguards off? You may have a crimped or loose gas tube.

 

[FreeWillie]

What upper is on that lower?

 

[bullseye]

If you have a Stag, swap out the upper and see what results, if it fires fine, your buffer would be a real good place to look, if it continues, go to the upper and look at that gas tube carefully. It may be crimped or clogged ( sorta like Bill Clintons artery ) and the clog is intermittent, no stents here. Replace the tube, improper removal/installation of the handguards could have nipped it. Your not getting enough pressure to move that bolt properly.

 

[Nicole]

You didn't let Nicole shoot it did you? She likes to break AR's.

Even *if* that was true, I'd like to point out that things do break when you actually belong to a gun club and go shooting once or twice a week instead of only sending rounds downrange a few times a year at NES events.

 

[StoneBear]

I recently installed a daniel defense quad rail fore grip on it. I am taking it off right now and am going to take a look.

About the manufacturer of the upper. I dont know, it has no external markings. Ill post a pic in a minute.

 

[Blitz1]

Even *if* that was true, I'd like to point out that things do break when you actually belong to a gun club and go shooting once or twice a week instead of only sending rounds downrange a few times a year at NES events.

Ouch!!

Precisely the reason I'm getting the Sig, so I can afford to shoot it once or twice a week. Not so easy with .308.

Besides you broke it on the 1st couple of shots.

XXXOOOXXX

 

[StoneBear]

Not having luck posting the photos, all photos have to be web based?

I got the hand guard off and there is a very slight bit of wiggle on the gas tube. Possibly more telling is a some carbon type buildup on the barrel where the gas tube exits the block and directly below the gas tube.

 

[StoneBear]

Here are a few photos. Notice the black build up on the gas tube and white residue under the gas tube on the barrel. Not sure if this is indicative of a problem or normal.

 

[LoginName]

If you have a Stag, swap out the upper and see what results, if it fires fine, your buffer would be a real good place to look, if it continues, go to the upper and look at that gas tube carefully. It may be crimped or clogged ( sorta like Bill Clintons artery ) and the clog is intermittent, no stents here. Replace the tube, improper removal/installation of the handguards could have nipped it. Your not getting enough pressure to move that bolt properly.

This.

Swap out the upper (assuming you have access to one or know another AR owner), and check the results.

At the very least it will aid in narrowing down where the problem is.

 

[StoneBear]

Yes, it seems like a good idea. I know these rifles are supposed to be modular, but there often seems to be some variability. Is there any concern of damage to the Stag upper? I dont want to F' up my baby, and have another on injured reserve. If not, Ill give it a try tomorrow AM.

 

[Skald]

Since you tried the mags and such, it could be the BCG that, odds are, wasn't properly staked. See if you can borrow a friends BCG, and if that turns to be the case have yours properly staked.

 

[Mike_Diako]

I would inspect the gas system for any leaks as well as make sure you have the correct buffer installed as well. Judging by the white residue I would say that you are leaking gas.

 

[abomb60]

Since you tried the mags and such, it could be the BCG that, odds are, wasn't properly staked. See if you can borrow a friends BCG, and if that turns to be the case have yours properly staked.

If you're getting stove pipes then you have a low pressure problem ... duh . This is normally caused by:

1. Loose gas key - Torque those bolts down and stake properly
2. Misaligned gas rings - fix alignment or replace with 1-piece ring
3. Clogged up gas tube - been shooting .22 lately?
4. Effed up gas tube - replace

For #4 I had a bushmaster I bought at Riley's a few years back that just wouldn't run right. Short stroking & stove pipes all day long even with full power NATO spec SS109 ammo. Turned out the top of the receiver end of the gas tube was worn flat causing a pressure leak. New gas tube and it was 100%.

 

[Remsport Mfg]

StoneBear where do you live? Please drop by the shop with your gun we can get it running.
We are in Ludlow MA that is ex 6 off the Turnpike.It will be worth the trip.
Thanks
John
413 579 1994

 

[bullseye]

StoneBear,
Mike beat me to the pics, the white would indicate a potential ( highly probable leak). I wouldn't worry about swapping out uppers, their good to go. In fact I have several AR's and if you want, I would be more than willing to go to the range with you or you could come to my place ( range ) in Andover CT. I'll bring a couple AR's and lets swap and check it out and fix it right.
Jim

 

[StoneBear]

I appreciate all the advice guys.

StoneBear where do you live? Please drop by the shop with your gun we can get it running.
We are in Ludlow MA that is ex 6 off the Turnpike.It will be worth the trip.
Thanks
John
413 579 1994

John that's a kind offer and I'll keep it in mind, but I live just outside Boston, so it would be a long haul. Ill give you a call if this issue persists and if I cant get it narrowed down and corrected.

StoneBear,
Mike beat me to the pics, the white would indicate a potential ( highly probable leak). I wouldn't worry about swapping out uppers, their good to go. In fact I have several AR's and if you want, I would be more than willing to go to the range with you or you could come to my place ( range ) in Andover CT. I'll bring a couple AR's and lets swap and check it out and fix it right.
Jim

Jim, another very kind offer and it sounds like a lot of fun at the range. Ill keep that in mind as well. But right now I am going to run the battery of tests I have gathered through this thread and see if I can ferret the problem out. Here is what I plan to do this weekend:

1- Perform the one round/lock open test and confirm that the firearm is short-stroking. Compare the struck primer of an Olympic fired shell and a Stag fired shell to check for firing pin wear.
2- Place my Stag upper on the Olympic lower. Hopefully this will tell me if the buffer spring is the offender. If she runs continue to 3.
3 - Place the Stag Bolt Carrier Group in the Olympic upper. If this runs well I can cross off damage to chamber end of the gas tube and gas block leakage. Continue to test 4
4- Place the Stag bolt in the Olympic Bolt carrier. This may tell me if the carrier is damaged or if the key is worn or improperly staked. Or if the the Olympic bolt itself is having issues.

If any of you guys see something else I should be trying or something else to be looking for during these tests let me know. I have access to a well running Bushmaster as well. Would it be redundant to perform the same tests using the Bushmaster components? Though it may help negate any false results. Hell, Ill be at the range all day.
Ill post the results either today or tomorrow.

 

[Devils Paintbrush]

I picked up two early 90's Olympic Ar's for a price I couldn't pass up and was having problems similar to what you are describing. Rifle would fire one round fine, but would either stovepipe or would never pick up the next round. I did some experimentation with my Bushmaster lower and the Olympic upper and it ran more reliably. I ended up ordering a new buffer and recoil spring for each rifle. When I got the new ones, I noticed that the originals (when I measured it with calipers) were a different size. The original Olympic buffer was .989 and the new one was I think (it is in the rifle now) .911. The original has some sort of sand like media in it. This worked for me, and both rifles are working properly. A new buffer and spring would be short money to see if it fixed it.


Here are a couple pictures of the original Olympic buffer I took out of my rifle.