Aero Precision M5 not cycling - Page 1

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[ARCHIVED THREAD] - Aero Precision M5 not cycling (Page 1 of 2)

Posted: 9/13/2018 6:46:39 PM EDT

Attached File

Tried shooting it for the first time today...after each round, I had to manually extract the casing. Sometimes it was pretty tough to get them out. I don’t believe the BCG is even cycling. 2 different types of factory ammo (Hornady & Federal).

I have no idea if it’s related, but I noticed all the casings have a noticeable scratch in the same place:

Attached File

It’s a build that the previous owner never fired; has all AP parts, black nitride BCG, and heavy buffer installed. Bolt has 3 gas rings on it. I really don’t know a lot about .308 AR’s.

Thanks!

Posted: 9/13/2018 7:02:09 PM EDT

[#1]

What kind of gas block? Is it adjustable? Can you see the gas tube?

If the BCG isn't moving AT ALL it could be the gas tube was accidently put in upside down... I've seen that before.

Posted: 9/13/2018 7:08:51 PM EDT

[#2]

I'm far from the best one to answer this... so I'll be curious to see what the pro's say..

The extraction issue like the there is an issue with the extractor, the extractor spring.. I'd take a close look at the extractor and then break the BCG apart... although... that scratch on the front of the casing might be a defect in the barrel or something in the barrel that the rounds may be catching on. If the casing is getting hung up and the extractor can't pull it out that might be the problem. That's a BIG problem, if the round is not seating correctly and there is some sort of impingement that may cause gas to escape around the round and back into the rifle. That could lead to a catastrophic failure. You may want to check out the rim of the rounds for scratching and the primer for loosening.

Posted: 9/13/2018 7:10:02 PM EDT

[#3]

Quote History

Quoted:
What kind of gas block? Is it adjustable? Can you see the gas tube?

If the BCG isn't moving AT ALL it could be the gas tube was accidently put in upside down... I've seen that before.

View Quote

Uhhhh or what he said lol...

I'd still be concerned with the scratches on the casings.

Posted: 9/13/2018 7:53:01 PM EDT

[#4]

my guess to the scratching is the brass being scraped by the barrel extension lug. how many rounds did you shoot though? ive had ars with all new parts take maybe 20 rounds before things start to loosen up.

Posted: 9/13/2018 7:59:07 PM EDT

[#5]

Quote History

Quoted:
What kind of gas block? Is it adjustable? Can you see the gas tube?

If the BCG isn't moving AT ALL it could be the gas tube was accidently put in upside down... I've seen that before.

View Quote

Pic of gas tube:

Attached File

Posted: 9/13/2018 8:56:58 PM EDT

[#6]

Quote History

Quoted:

Pic of gas tube:

https://www.AR15.Com/media/mediaFiles/62477/243679B7-6886-473E-BA14-3EBB14EE6B02-670709.JPG

View Quote

Maybe it's just the pic... but it looks upside down to me. Can you tap out the retaining roll pin and pull the gas tube out and check? It's easy...

Posted: 9/13/2018 9:02:15 PM EDT

[#7]

Usually when the BCG does not move AT ALL... the gas tube is upside down... I've fit half a dozen builds from other folks over the years due to this.

You can also look to see if ANY gas has made it to the BCG.

Posted: 9/13/2018 9:13:18 PM EDT

[#8]

That gas tube doesn't look right, OP.

Posted: 9/13/2018 9:46:02 PM EDT

[#9]

Yep! Others already said it. Based on that pic the gas tube is upside down.

Posted: 9/14/2018 9:16:21 AM EDT

[#10]

Lol... first time I have seen that !

Good catch @Bowhntr6pt

At least it is an easy fix.

Posted: 9/14/2018 7:57:56 PM EDT

[#11]

Yep gas tube is upside down.

Posted: 9/14/2018 8:02:59 PM EDT

[#12]

Thanks guys....how does that impact gas reaching the BCG? I never would’ve guessed the tube orientation would be so critical.

Just to be sure, when everyone is saying “upside-down”, does that simply mean the tube needs to rotate 180 degrees, or does it need to flipped around so the end by the receiver flips to the muzzle side?

And how do I go about correcting it? Like I said my AR10 knowledge is about nil

Posted: 9/14/2018 8:10:56 PM EDT

[#13]

Quote History

Quoted:
Thanks guys....how does that impact gas reaching the BCG? I never would’ve guessed the tube orientation would be so critical.

Just to be sure, when everyone is saying “upside-down”, does that simply mean the tube needs to rotate 180 degrees, or does it need to flipped around so the end by the receiver flips to the muzzle side?

And how do I go about correcting it? Like I said my AR10 knowledge is about nil

View Quote

Just push out the roll pin and spin it 180 degrees. Then put the pin back in.

eta: How it impacts the gas flow is that the hole in the gas tube does not align with the hole in the gas block when it's upside down.

Posted: 9/14/2018 10:13:19 PM EDT

[#14]

Quote History

Quoted:
Thanks guys....how does that impact gas reaching the BCG? I never would’ve guessed the tube orientation would be so critical.

Just to be sure, when everyone is saying “upside-down”, does that simply mean the tube needs to rotate 180 degrees, or does it need to flipped around so the end by the receiver flips to the muzzle side?

And how do I go about correcting it? Like I said my AR10 knowledge is about nil

View Quote

Yes... upside down as in 180-degrees... not backwards as in needing flipped. Knock pin out, rotate, reinstall pin.

The single gas hole is on the side of the tube before the crimped/sealed part. Note the hole THROUGH the gas tube AFTER where the tube end is crimped/sealed, that's for the pin. Then notice the single hole at the bottom, before the sealed crimp area. The hole must be oriented down facing the gas port hole in the barrel.

Posted: 9/15/2018 5:53:34 AM EDT

[#15]

Am I the only one who can't wait for an update on this thread?

Posted: 9/15/2018 3:20:57 PM EDT

[#16]

@OBird did you fix it yet?

Posted: 9/15/2018 4:15:50 PM EDT

[#17]

Not yet; really busy this weekend...tomorrow afternoon hopefully

Posted: 9/15/2018 9:14:18 PM EDT

[#18]

i'm also waiting to see how this turns out...

Posted: 9/16/2018 8:20:55 AM EDT

[#19]

Without trying to sound like a jerk... if whomever assembled it put the gas tube in upside down... I sure as heck would double check the rest of the build.

They may have just had a "Dooh" moment, but....

Posted: 9/16/2018 10:03:18 AM EDT

[#20]

Id probably replace the whole tube, its bent so it'll fit into the lower and that will either be a pain to re-assemble correct or at least be aesthetically a minor issue. But flipping right side up will definitely fix the problem.

Posted: 9/16/2018 8:52:22 PM EDT

[#21]

Is this now a safe thread?

Posted: 9/16/2018 9:36:56 PM EDT

[#22]

My stupid punch set is all tapered so I couldn’t get the roll pin out

Will have to continue....after I get new punches...and possibly a new gas tube

Posted: 9/16/2018 9:55:19 PM EDT

[#23]

Quote History

Quoted:
My stupid punch set is all tapered so I couldn’t get the roll pin out

Will have to continue....after I get new punches...and possibly a new gas tube

View Quote

I'm just fucking with you.

Posted: 9/16/2018 11:24:04 PM EDT

[#24]

At least it's an easy fix...

Posted: 9/17/2018 8:12:37 AM EDT

[#25]

Quote History

Quoted:
Id probably replace the whole tube, its bent so it'll fit into the lower and that will either be a pain to re-assemble correct or at least be aesthetically a minor issue. But flipping right side up will definitely fix the problem.

View Quote

Vilya makes a good point. If the tube has been forced to fit then you may have an alignment issue with the upper, gas key or both once it is properly oriented. I'd probably order a new one just to avoid headaches.

Posted: 9/17/2018 1:59:46 PM EDT

[#26]

At this point, I would also check the gas key on the bcg to make sure it's not mangled from banging against a misaligned tube.

Posted: 9/18/2018 9:20:54 AM EDT

[#27]

Quote History

Quoted:
At this point, I would also check the gas key on the bcg to make sure it's not mangled from banging against a misaligned tube.

View Quote

Previous owner never fired it, OP was hand-cycling individual rounds....if the gas key is mangled from hand-cycling a few rounds, then OP might could want to buy a whole new BCG if that's the quality standard.

Posted: 9/18/2018 12:00:25 PM EDT

[#28]

Attached File

Just when I thought I had seen it all..........

That rifle absolutely should NOT cycle the BCG when fired. If it did, something would be wrong with the world.

I've seen plenty of gas tubes installed backwards, but never upside-down.

Posted: 9/26/2018 3:53:43 AM EDT

[#29]

I'd bet that either alcohol was present during assembly, or, the workshop is very dimly lit. visualizing: 15w lightbulb dangling from a cord...

or, talking on the cell phone while installing gas tube.

Posted: 9/28/2018 7:23:34 PM EDT

[#30]

Day 15

Posted: 9/28/2018 7:31:54 PM EDT

[#31]

Posted: 9/29/2018 3:35:57 PM EDT

[#32]

@OBird

Any update?

Posted: 9/29/2018 8:41:58 PM EDT

[#33]

Quote History

Quoted:
@OBird

Any update?

View Quote

Yup:

Attached File

That roll pin will simply not budge.

Posted: 9/29/2018 9:15:10 PM EDT

[#34]

Quote History

Quoted:
That roll pin will simply not budge.

View Quote

in which case you might have to remove the gas block off the front of the barrel:
loosen and remove muzzle device;
loosen set screws on gas block;
pull gas block and gas tube assembly off the barrel.

inspect the gas block though the set screw hole to see if gas tube is installed upside down (blocked).

Posted: 9/29/2018 9:32:28 PM EDT

[#35]

Quote History

Quoted:

Yup:

https://www.AR15.Com/media/mediaFiles/62477/image-687607.JPG

That roll pin will simply not budge.

View Quote

No way... send that upper to me, I'll square it away for free.

Posted: 9/30/2018 2:37:13 AM EDT

[#36]

Quote History

Quoted:
Yup:

https://www.AR15.Com/media/mediaFiles/62477/image-687607.JPG

That roll pin will simply not budge.

View Quote

That's pretty impressive. I too will fix it for free if you cover the shipping. I'll even function check it before I send it back. Do you know what length that gas tube is?

Posted: 9/30/2018 8:34:28 PM EDT

[#37]

Same here. I'll fix it.

Posted: 10/1/2018 7:41:14 PM EDT

[#38]

It's possible there's so much tension on the gas tube being bent upward like that, that the pin has too much pressure against it holding it in place.

Maybe back off the gas block screws, tap it off the barrel, and see if freeing it from that tension helps?

or just dremel and a cutoff wheel CAREFULLY cut thru the gas tube and see if that helps.

ETA: Get a proper roll pin punch as well.

Posted: 10/4/2018 2:42:47 PM EDT

[#39]

Thanks for the offers guys! I might just do that....but the seller offered to buy it back due to the issues. He didn’t build it, someone else did...but it was sold at a silent auction for charity so I feel kinda bad. I got everything in the top picture for $1150, minus the sling/bipod/foregrip.

Good enough deal that it’s worth keeping it and working the bugs out?

Posted: 10/4/2018 4:34:38 PM EDT

[#40]

It should cost you $20 to fix it. Why would you return it over that? Buy another tube, buy a proper roll pin punch, and take the 5 minutes to fix it.

Posted: 10/4/2018 5:57:41 PM EDT

[#41]

Quote History

Quoted:
Thanks for the offers guys! I might just do that....but the seller offered to buy it back due to the issues. He didn’t build it, someone else did...but it was sold at a silent auction for charity so I feel kinda bad. I got everything in the top picture for $1150, minus the sling/bipod/foregrip.

Good enough deal that it’s worth keeping it and working the bugs out?

View Quote

As long as everything else is "A-Ok" ... then I keep it, Or even if no threads were stripped or such... I'd keep it.

The GB and gas tube would be a very cheap and easy fix.

Posted: 10/20/2018 4:26:06 PM EDT

[#42]

Dremel cut that gas block 98% thru to barrel then use a screw driver to crack it off.

Then new (Adjustable) gas block and gas tube

Posted: 10/21/2018 7:40:21 AM EDT

[#43]

Might as well check the torque on the barrel nut while you have it apart. Who know what else he assembled wrong before you got it.

Posted: 10/21/2018 2:36:34 PM EDT

[#44]

Quote History

Quoted:
Dremel cut that gas block 98% thru to barrel then use a screw driver to crack it off.

Then new (Adjustable) gas block and gas tube

View Quote

Don't do this..

Posted: 10/21/2018 2:44:25 PM EDT

[#45]

You need better punches. I've bent tons on the gas tube.

Got some punches from Germany, Rein something or another. Been good for a few years now.

Keep the rifle, get some better punches, a small ball peen hammer and you'll be good to go.

You won't need a new gas block, it's not kinked. I doubt there is any damage to the portion going to the gas key.

Posted: 10/21/2018 6:11:47 PM EDT

[#46]

I purchased cheap US punches from HomeDepot and they're not tempered, my 1/16" looks similar. Junk. My Chinese Wheeler punches are trash also, but they're tempered and do not bend easily.

Trash your gas tube. Buy a single high quality 1/16" punch. You should also spend the money on a premium gas tube. I use Colt Defense, many commercial tubes are trash. can use cheaper punches for the larger ones if you have to. Inspect your BCG for damage. It looks like your barrel may have an issue use chamber guages to check specs. Go/NoGo. If everything checks out reinstall new gas tube and lube. Function check and you should be good to go.

Posted: 10/21/2018 6:24:18 PM EDT

[#47]

Anyone telling you to use regular punches on a roll pin is a retard.

Roll pin starters:

Roll pin punches (note the nipple which goes in the hole to support the interior diameter, while the punch drives the pin):

Get a set of both. Using the wrong tool for the job is no reason to get pissed when the tool fails.

Posted: 10/21/2018 8:29:24 PM EDT

[#48]

Quote History

Quoted:

...
Roll pin starters:

https://images-na.ssl-images-amazon.com/images/I/61AArEcltOL._SL1500_.jpg

Roll pin punches (note the nipple which goes in the hole to support the interior diameter, while the punch drives the pin):

https://media.mwstatic.com/product-images/880x660/Primary/191/191653.jpg

Get a set of both. Using the wrong tool for the job is no reason to get pissed when the tool fails.

View Quote

+1 on the correct punches. If you intend to Assemble AR's or maintain them, then getting the correct tools is an early investment which will go far to avoid later, greater expenses to replace ruined components.

Posted: 10/22/2018 8:06:59 PM EDT

[#49]

I've never used roll pin punches and I've never ruined a split pin or roll pin? Split pins and roll pins are cheap and should be replaced after they've been installed and removed for the most part. If these punches help you get the job done, then wonderful. But saying they are a requirement is absurd. I use a surgical clamp to start pins, and hold small parts during assembly.

Posted: 10/23/2018 1:45:29 PM EDT

[#50]

Quote History

Quoted:
Anyone telling you to use regular punches on a roll pin is a retard.

Roll pin starters:

https://images-na.ssl-images-amazon.com/images/I/61AArEcltOL._SL1500_.jpg

Roll pin punches (note the nipple which goes in the hole to support the interior diameter, while the punch drives the pin):

https://media.mwstatic.com/product-images/880x660/Primary/191/191653.jpg

Get a set of both. Using the wrong tool for the job is no reason to get pissed when the tool fails.

View Quote

Maybe Im just a dumbass, but the starter punches never work well for me.

The holders do though.

These are what I got.

They have held up great. I also got the Gracie I think, starter punches, and the small ones peened over like nothing. Didnt think I was hitting it hard enough to do that, but it did. AND didnt damage the roll pin at all, just the punch. I havent sent the back to Gracie yet, but they will replace them.

[ARCHIVED THREAD] - Aero Precision M5 not cycling (Page 1 of 2)

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