Armalite AR-10T FTF Help...

[AR_ART]

FINAL UPDATE 3/29/2014

Yeah, hopefully "FINAL"! Which means good news. 100 rounds down range from full magazines and NOT ONE issue! The rifle is seriously super accurate so the tight groupings with surplus ammo was no surprise to me. But NOT ONE single feed issue (or any issue for that matter). It fired great from the very first round to the last...

Well, has happened was I took Bert's advice. He believed it was just the rifle had not been broken-in completely and based on my description of cleaning and lubing of the rifle I was running it too dry.

So in the past couple weeks, I left the magazines fully loaded and for a couple days I left the bolt open. Bert recommended a particular gun lube which I didn't have, but he said in a pinch I could use 5 wt motor oil, which I did.

I'm very happy as this thing is really super accurate but the feed issues were pissing me off. I was close to just dumping it off relatively cheap… Glad I didn't.

Thanks for those who followed my thread and made suggestions.. Hope this helps someone in the future!


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UPDATE 3/23/2014:

Haven't been to the range. Hoping I'll be able to make it today, but with the snow/rain mix we had, I'm sure its gonna be muddy out there, so that might change things for today.
In a nutshell. I worked with BPTactical (Bert) who was very helpful and informative. He believes there are most likely two main culprits. First being it still hasn't had enough rounds down range (I know someone else mentioned this too). And secondly I'm probably running it too dry, especially as few round as it has down range and just the way I tend to lube my firearms. He also gave me a few other suggestions regarding helping the magazine springs and buffer spring "settle"...

He also helped me appreciate the rifle more as he has one and gave me a bit of a walk-through on it, like based on the serial number, it actually has a match-grade barrel...

So while I'm not expecting it to feed reliably immediately, hoping if I shoot enough today, I'll be able to start seeing a difference!



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UPDATE 3/9/2014:

Finally made it to the range this morning and tried some of the suggestions and approached it "methodically".

Grabbed the wrong ammo can (almost empty), so I cannot say 100% that I've isolated the issue but I'm pretty confident. It appears to be a "magazine" issue. It appears to be "hanging up" when it goes to feed the next round. While it can be random, its definitely happens almost 100% of the time with a full, 20 round magazine. With only 3 rounds in the magazine it only happens less than 10% of the time. But even when I started with say 12 and it got down to three rounds it did not always feed the last 3 rounds reliably (Anything between the 18 to mag empty would also intermittently feed...

I tested with 3, 20 round magazines, all Armalite Brand, 1 BNIP, and the other 2 are fairly new meaning less than 40 rounds in each...

The funny part is that it appears ALL the magazines are hanging up to some degree. I noticed with 2 of the magazines, if its say at 18 rounds full, and I pull the charging handle back, as I watch through the ejection port at the magazine, I notice there is a slight but observable delay as the next round pops up a little bit in the magazine. Its as though the rounds aren't in a position to be taken up by the bolt and loaded, that for some reason they aren't moving into the correct position within the magazine. Very odd that all three magazines do this.

BUT at the same time I think, "How can all three magazines have the exact same problem"? Is there some "force" or something being applied to the magazine causing all three to act the same way?

Now admittedly when I got these mags, I've just wiped them down and didn't take them apart and clean them. I took them all down and I don't see anything that would make them hang. Lightly lubed them… so we'll see..

Any other suggestions would be appreciated!

END 3/9/2014 UPDATE….



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I've got an Armalite AR-10T and it pretty consistently Fails To Feed. Its only feeding successfully at about 10% of the time. I have to pull the charging handle to load the next round. Otherwise, I squeeze the trigger and I get a click..

It does feed when the charging handle is pulled all the way back and the release used or manually released.
It does successfully extract the spent case.
I'm using steel AR-10T magazines, not some cheapos. I've tried using all of my 6 magazines with the same results
I've tried using Factory Ammo, Surplus Ammo, and my "hand" loaded ammo (168 gr bullet, 42.1 grs. IMR-4064…works great in my bolt action) with basically the same results.
I've measured the buffer spring and buffer itself and compared it the Armalite specs, and its all within spec.
Parts are well lubed and there does not "appear" to be anything hanging it up or preventing it from moving rearward. I'm no expert but I don't see anything obvious.

I've put the Magpul PRS stock on it. My AR-10T does have the rifle extension tube and not the M4 tube. The PRS was just the stock no spring or tube. It had the same failure rate even with the oem "stock".

I'm not sure what to do besides taking it to a gunsmith. I'm thinking of trying a "softer" buffer spring but having problem finding specs on spring rates on the various sites that sells springs...

Any thoughts would be appreciated!

Thanks

[earplug]

The bolt is not going back far enough to pick up a round. Whats the chance that the gas system is leaking or ?

[AR_ART]

How do I check this? Would there be visual signs of a gas leak, like carbon in an odd place?

[ChunkyMonkey]

Look for evidence of gas leak around the gas block & tube area.

[BPTactical]

Check the screw that is holding the PRS on. Make sure it is a vented screw.
Indicators of a gas leak should be obvious, carbon deposits around the block/barrel, block/gastube etc..

[SideShow Bob]

What Bert said, without the "vented screw" the buffer acts as a piston and compresses air in the tube.

Had the same problem with an Ace stock until I replaced the upper screw that attached the butt plate to the tube.

[AR_ART]

Thanks guys! Will check it!

[SideShow Bob]

Also is the rear adjustment all the way down to where the rubber butt pad could be pressed against the screw and obstructing the vent hole in the screw if you do have the proper screw installed ?

[AR_ART]

Okay, so I took a look at it… I have the proper vented screw in place. The butt pad is adjusted away from screw (and was when I was shooting it). I didn't see any carbon around the front gas block.

There is a bit of carbon in the upper receiver at the end of the gas tube area, but nothing "excessive" or more so than I've seen in my AR-15….

Reckon' a visit to BP Tactical is probably next on the list….

[SideShow Bob]

Is there excessive carbon around the area where the gas key attaches to the bolt carrier ? Have you checked the rings on the bolt itself ?

[AR_ART]

No excessive carbon at the key/bolt interface. Some carbon, but nothing excessive. The bolt looked good, very little carbon on it.

The previous owner did install a Gieselle trigger on it. Is there a possibility of any type of interference? It does't appear to be, but just wondering if there "may be" something there...

Thanks again for all the help I do appreciate it!!!


Is there excessive carbon around the area where the gas key attaches to the bolt carrier ? Have you checked the rings on the bolt itself ?

[mrfish83]

Here are a few ideas:

1) Under gassed / Short stroking - Try loading 1 round in a magazine, load and fire that round, see if the BCG locks back on the empty mag (after firing). I'd try this at least 3-5 times. If the BCG doesn't lock back on an empty mag you may not be getting enough gas. Some possible problems are a leaking gas block, gas block not aligned, too heavy of a buffer spring or buffer, not properly lubed. I had a DPMS 260 which from the factory had a mis-aligned gas block (although it also leaked), and was super dry. It started to run much better after re-aligning the gas block and lots of lube.

2) Over gassed - If it is over gassed, the BCG may be coming all the way back after firing and skipping over the top of the mag fast enough where it misses picking up the next round. If this is occurring you may want to try a heavier buffer spring and/or buffer.

Are you shooting suppressed?
Do you have an adjustable gas block?
How many rounds have been fired?

When brass is ejected, where is it landing? Both distance, and relative position to you (i.e. 2 o'clock, 4 o'clock, etc)

[AR_ART]

Dang, didn't think to check it at the range if it was locking back after the last round. I think I got fed up of the FTF, I don't know that I got to that point. Well simply means a range trip later this week!

Not shooting suppressed…
No Adjustable gas block...
Less than 100 rounds down range...

Now that you mention it, it did fail to eject twice. Looks like it started to eject but not fast enough as it 'tried' to put the empty case back in the chamber. The bolt was only partially closed (1/4 of the way) as it looked like the lip of the case hung up on a lug...

When it does Its going at about the 3 o'clock position….



Here are a few ideas:

1) Under gassed / Short stroking - Try loading 1 round in a magazine, load and fire that round, see if the BCG locks back on the empty mag (after firing). I'd try this at least 3-5 times. If the BCG doesn't lock back on an empty mag you may not be getting enough gas. Some possible problems are a leaking gas block, gas block not aligned, too heavy of a buffer spring or buffer, not properly lubed. I had a DPMS 260 which from the factory had a mis-aligned gas block (although it also leaked), and was super dry. It started to run much better after re-aligning the gas block and lots of lube.

2) Over gassed - If it is over gassed, the BCG may be coming all the way back after firing and skipping over the top of the mag fast enough where it misses picking up the next round. If this is occurring you may want to try a heavier buffer spring and/or buffer.

Are you shooting suppressed?
Do you have an adjustable gas block?
How many rounds have been fired?

When brass is ejected, where is it landing? Both distance, and relative position to you (i.e. 2 o'clock, 4 o'clock, etc)

[mrfish83]

Dang, didn't think to check it at the range if it was locking back after the last round. I think I got fed up of the FTF, I don't know that I got to that point. Well simply means a range trip later this week!

Not shooting suppressed…
No Adjustable gas block...
Less than 100 rounds down range...

Now that you mention it, it did fail to eject twice. Looks like it started to eject but not fast enough as it 'tried' to put the empty case back in the chamber. The bolt was only partially closed (1/4 of the way) as it looked like the lip of the case hung up on a lug...

When it does Its going at about the 3 o'clock position….

Some ARs will take some time to break-in and will become smoother as you get more rounds down the pipe. That being said, it sounds like you have bigger challenges to deal with.

When the brass ejects at 3 o'clock, does it land right next to you (like you could reach over and grab it)?
Does the fired brass have strong extractor (not ejector) marks (may look like the side of the rim is bent back or broken off)?

I'd recommend trying the "1 round in the mag test (bcg lock back)" several times and see what happens. You could try different ammo too if you have it.

[SideShow Bob]

To the O.P., have you figured out the problem yet ?

[AR_ART]

Not yet. I've not had a chance to hit the range to check the 1 round in the magazine scenario yet… Gonna try this weekend. But examination by my "untrained eye" hasn't revealed anything to me… :)

[SideShow Bob]

Have you looked down in the buffer tube to see if the previous owner put one of these in there ?

http://www.midwayusa.com/product/154800/doublestar-twang-buster-buffer-pad-ar-15-delrin

Lots of bad reviews.

[SA Friday]

There is one and only one thing that stops a BCG from fully cycling; lack of energy. That lack of energy can be from two things, lack of initial energy transfer or loss of energy to a secondary location after the initial energy transfer. Basically either the gas isn't enough to cycle the system or it is enough but something is binding. You have to eliminate either one possibility or the other. Once you determine the gas system is OK, you have a binding issue; mag, trigger, buffer/tube. If you find and resolve a gas system issue then ops test to determine if there is also a binding issue. Short of previous inputs the one thing I think is interesting is all of your mags are the same. This eliminates the possibility of a bad mag, but could mean that the current mags you are using are over inserting and binding against the bottom of the BCG and causing it to short-stroke. When an AR short-strokes, it cycles differently and feels different. The buffer doesn't bounce off the end of the tube and you should be able to feel that it's not "bouncing". Intermittent cycling issues points to more of a binding issue and less of a gas system issue. Whatever is binding can be affected to make it worse or better and therefore intermittent. This also makes me think it might be the mag rubbing against the bottom of the BCG. Try a different mag and try shooting it resting on the mag and off of the mag.

[AR_ART]

Thanks some really good additional points! I will also pay attention to those things at the range. If the magazines were rubbing on the bolt would there be some type of odd looking ear on the bottom of the bolt? Now that you mention it though, I don't remember hearing that "twang" in the buffer tube like in my ARs. Well, will definitely compile this list of good ideas to remind me at the range!

Sideshow Bob, I don't see one of those in my buffer tube...

[AR_ART]

Made an update on the Original post.. Figured it might be easier than scrolling to the end of the thread… :)

[SideShow Bob]

Are the magazines the Gen1 or the Gen2 Armalite AR 10 magazines ? Or could they be the newly offered experimental Armalite AR 10/M1A dual compatible magazines that Armalite is offering for feedback from customers ? (I'm not saying that you violated state law by bringing these into the state.)

From what I understand the Gen1 Magazines were modified M14/M1A magazines and the Gen2 magazines are specifically built for the Armalite AR 10.

[AR_ART]

Thanks! Something I'll need to look at.. Didn't realize there was a difference or know there were even differences within the AR-10 magazines (the proprietary) ones.... I got these prior to the "ban" so they are Colorado legit...

I'll see if there is a way to "know" if they are Gen 1 or Gen 2... If the new ones came out after the ban, I definitely don't have those ... Another thing to check! Thanks!

[SideShow Bob]

And here is a quote from Armalite concerning the AR 10 "A" rifles just to add some more confusion to the magazine issue.......

The AR10 "A" was put out in late 2012 I think, and if you bought yours used, you may want to contact Armalite CS with you serial number to find out just exactly which model
you have. And which magazine you should be using.

Edit : copying and pasting didn't work.

This link explains what I was trying to say......

http://www.thetruthaboutguns.com/2012/01/foghorn/new-from-armalite-ar-10a/

[SAnd]

http://www.armalite.com/images/Tech%20Notes/TECH%20NOTE%2071%20%20AR-10%20Magazines%20090603%20Rev%200%20Final.pdf
TECHNICAL NOTE 71: AR-10 MAGAZINES AND BOLT STOPS

http://www.armalite.com/images/Tech%20Notes/TechNote101.pdf
TECHNICAL NOTE 101: VISUAL DIFFERENCES AMONG M15,AR-10B, AND AR-10A COMPONENTS

http://www.armalite.com/Categories.aspx?Category=35e8a0b0-7e71-4af3-b335-53f4a7dc8f08 (http://www.armalite.com/Categories.aspx?Category=35e8a0b0-7e71-4af3-b335-53f4a7dc8f08) This is a link to the Armalite Tech Note index. The first link Teck Note 71 has pictures and description of the M14, and the Gen I and Gen II mags. The second link has pictures and descriptions on the differences between the "A" and "B" AR 10s.

[AR_ART]

Thanks for all the info!!! Checked-out the Tech Bulletins, its definitely all the "B" model. Checked mags, and the rifle… I opened it up and inserted a mag, both loaded and empty, moved stuff around, and couldn't see anything obvious….

I'm thinking its time to see Bert!

[SideShow Bob]

It's been awhile, any updates as to what the problem was ?

[AR_ART]

Thanks for prompting me! I had planned on updating the original post earlier this week if I got a chance to go to the range. But as usual work got in the way ;)

So, I've updated the main post… But in a nutshell here. Haven't been to the range since I worked with Bert. No work on the rifle, suggestions though about lubing and getting some range time with it to break it in. He didn't think there was anything "wrong" with the rifle….

Hoping I get to the range today!

[SideShow Bob]

Per your update, funny thing mine (carbine version) ran 100 % out of the box. Granted I thoroughly cleaned and lubed it very well, took all the magazines out of the packaging and took them to Bert to run through his parts washer then lubed them lightly.
It still runs with no problems even after taking it to Bert for modifications. [Tooth]

If you are still having feeding problems, maybe I can tag along with you next time you go to the range (Hint, Hint) and try my magazines to see if your magazines are the problem so that you can contact Armalite about fixing them.

[AR_ART]

That sounds good to me! Didn't make it to the range today.. The honey-do list was loonnnng!

[AR_ART]

Updated! See original post! :)

[ChunkyMonkey]

Updated! See original post! :)

Congrats.. would love to go to the range with you sometimes. [Flower]

[AR_ART]

That would be awesome!

Congrats.. would love to go to the range with you sometimes. [Flower]