LR-308 not ejecting cartridge.

[thossoma@pm.me]

Just built my first AR-10 / LR-308 from an 80% arms lower and a CBC INDUSTRIES Upper.  https://www.cbcpfa.com/products/ar-10-upper-assembly-18-308-win-110-15-cbc-industries-keymod-ar-10-handguard-rail/ 

My buffer.  https://www.midwayusa.com/product/1021956650

My buffer spring. 

https://www.midwayusa.com/product/1019426458

My BCG

https://www.cbcpfa.com/products/ar10-bolt-carrier-group/

I use Magpul magazines.

If I manually cycle the bolt with the charging handle, I can smoothly eject cartridges and load cartridges without issue.  It will also lock the bolt back after the last round. 

When I start shooting, it is a different story.  I put one round in the mag and put it into battery.  After I touch it off, the bolt is still in battery and the round didn't eject (about 5% of the time it will eject in this scenario) and the bolt doesn't lock back.  If I put two rounds in the mag, I will slam the first round in and touch it off and then look at the ejection port and find the second round pushing up against the spent round still in the chamber.  So it tries to feed the next round, but failed to eject the last round.

 

 

 

 

 

 

 

[98Z5V]

What's the story on your barrel and gas system?  It's clear to see that the gas tube is the right length.  But is that midlength, rifle, what's the barrel length, what's the gas port diameter?

What's the details on the internal depth on the receiver extension?  It's obviously a carbine receiver extension, based on the carbine buffer you posted a pic of.  What's the internal depth on it?  And what's teh length and weight of that buffer?

reading this first will help - it explains many of the necessary details we need, in order to try to ATTEMPT to solve a functional issue, over the internet...

 

Edited August 23, 2021 by 98Z5V

[thossoma@pm.me]

The buffer is just over 5 oz.

The barrel is 18" 1:10 twist.

.750 Low Profile Gas Block

I will get the rest of the info soon...

[98Z5V]

5 minutes ago, thossoma@pm.me said:

I will get the rest of the info soon...

You didn't read that thread when @Armed Eye Doc directly linked it for you - before you said you would, and started this thread.

Make sure you read that link that I just posted, and understand the level of detail needed...  and THEN post back.

Thanks in advance.   It's just a guessing game and waste of time, if you can't provide all those details that are necessary. Blind-folded, and playing darts, we are... 

Edited August 23, 2021 by 98Z5V

[Albroswift]

11 hours ago, 98Z5V said:

guessing game

Following along for fun.

 

@thossoma@pm.me Don't be surprised or bummed when you purchase a 308 premium quality craftsman build crafted with high quality materials and backed by a lifetime warranty, and it don't run. Unfortunately it's common. Fortunately it's not that expensive or hard to fix.  We'll get you running like a $hit through a goose but we need lots of information to digest. 

[edgecrusher]

Your spring is absolutely incorrect for the buffer, but, what is the internal depth of your buffer tube. It sounds like you have compounding issues. Answer 98’s questions and my question, we will probably ask more… such as what was your lubrication lever for break in? What ammo? Probably more to come but so far these are all standard and need answering to help from our couches.

[98Z5V]

@thossoma@pm.me, from the links you provided, that's a midlength barrel, and taht gas tube is perfect, so that part is good.  18" midlength-gas .308 Win barrels need a gas port diameter of 0.080"~0.085" to function correctly.  So, for the gas system, the gas tube ir right, if the gas block is on there straight, that only leave gas port diameter as a problem - which I think it is.  It's probably 0.070", from patterns that we've seen as issues, on that barrel config.

Recoil system - that buffer looks just like a KAK Shorty, but it's AR Stoner.  At 5.3oz in a stainless body, it's almost guaranteed it's a 2.500" buffer.  That means your internal depth inside the receiver extension should be 7.000".  Not overall length - internal depth.

^^^   If that recoil system information is true, then you can fix that recoil system with a Sprinco Orange spring.  Drill up that gas port after that - and your gun should run like a sewing machine.

[thossoma@pm.me]

Ok, here goes everything I got!

1. NOT an armalite system

2. Buffer weighs 5.3oz.  my scale doesn't show last digit.

https://www.midwayusa.com/product/1021956650

3. Buffer is 2.5"

4. Buffer tube is 7"

5. Buffer spring is this one ...https://www.midwayusa.com/product/1019426458

6. This rifle is carbine length with an 18" barrel

7. Gas tube is just under 12"

8.

9.

10.

11. Gas journal is .75" and port is just smaller than 5/64", but bigger than 1/16".

12. I will take photos of the malfunction as soon as I can get out and shoot again.  Planning on this week 

Ammo I've shot is...(same results on both)

 

 

 

 

[98Z5V]

20 minutes ago, thossoma@pm.me said:

11. Gas journal is .75" and port is just smaller than 5/64", but bigger than 1/16".

 

5/64" = 0.0781", and 1/16" = 0,.0625" - so we're somewhere in there.  Carbine gas tubes are 9 3/4" long, to that's a midlength gas tube.

So, end result is this:  Get the Sprinco Orange spring in there, keep the rest of your recoil system parts besides that spring. The 5/64" bit won't go, and that 0.078", which would be too small anyway.  You'll need to open that gas port up a bit.  It'll run after that...

[Armed Eye Doc]

And lube the crap out of it before you shoot it.  It should be more wet than you think is needed, especially during the break in period.

As far as your scale, it looks like it is measuring in pounds.  Change it to ounces to get a better reading.

[98Z5V]

I was gonna say that - hit that UNIT button...  

[thossoma@pm.me]

So my current options for drill bits are using the 5/64 (0.078125) to make it slightly bigger, or using 3/32 (0.09375) to make it over the size you specified?  

As far as the scale, it specifies lbs.ounces.fractions of an ounce.  So the picture shows 1.2.2.  1 pound 2.2 ounces. The display is just messed up.  Not sure why it doesn't say lb.oz or something like that.

Thank you for your attention to my rifle issues.  I have purchased the orange spring and will report back after I do some test firing.  And I'll wait to hear from you guys about the gas port drill size.

I have been pretty liberal with the gun oil on the bolt especially.  I'll keep that up.

[thossoma@pm.me]

How about this drill bit?? .082". It's a #45 gauge drill bit.

Edited August 24, 2021 by thossoma@pm.me

[98Z5V]

Just go to ACE Hardware - there has to be one close to you, they're everywhere.  You're looking for Irwin numbered drill bits, and they're in a blue and yellow package.  For your barrel, I'd just drill it 0.085" and be done with it.  There's no need to test between 0.080"~0.085".  I know for a fact that 0.085" works well, from past experience on 18" midlengths with 0.750" journals, for .308 Win. 

You're looking and a #44 drill bit.  I use this reference all the time:

https://littlemachineshop.com/reference/drillsize.php?Source=Google&device=c&keyword=&utm_medium=referral&gclid=Cj0KCQjwjo2JBhCRARIsAFG667U19dp7wlL8YiGTJ1kF8u5-J5MdnWAKmLCl5Bw1AX8tCR2FQX11lK4aAkfZEALw_wcB

If your local ACE doesn't have a #44, get the #45.  It's smaller (0.082"), but will still run your gun.  Use the #45 and hog it out a little. #44 is your first choice, though.

This is what you'll see on the rack - look for that packaging:

Edited August 24, 2021 by 98Z5V

[thossoma@pm.me]

Thank you!  I will find the #45 drill bit and get it done!  I'll be in touch with the results.  So apparently I am under gassed and need more to get the job done.  It's not pushing my BCG back far enough to eject the old round and also lock back after the last round.  Correct?

[98Z5V]

15 minutes ago, thossoma@pm.me said:

Thank you!  I will find the #45 drill bit and get it done!  I'll be in touch with the results.  So apparently I am under gassed and need more to get the job done.  It's not pushing my BCG back far enough to eject the old round and also lock back after the last round.  Correct?

Correct, mostly.  YOU NEED THE #44 DRILL BIT!   Only try the 45 if they don't have a 44 at your store...

But - you don't have enough gas going through that barrel/gas tube, with less than a 0.078" gas port diameter, on that barrel configuration.  That part is accurate. 

[thossoma@pm.me]

Yes, sorry I mistyped.  Thanks again for your help!

 

[98Z5V]

SMOKE IT!  Drill it, and your guns runs now. I look forward to your shooting results.  

[Albroswift]

Go real slow and easy, lots of lube, wouldn't hurt to put a dowel in the bore. the slower you break through the cleaner the hole will be. Do you have a drill press?

[thossoma@pm.me]

Thanks for the tips.  I do have a drill press, would that be the smart choice?  I've actually never removed a barrel from an upper before, shouldn't be too hard right?  

I did get my Sprinco orange buffer spring in the mail.  Now I am just waiting on the #44 drill bit.  So please tell me if I'm wrong, but I am going to be drilling the hole that is on the barrel, not the hole on the gas block.  Also, worst case scenario if I go from under gassed to over gassed, I can always get an adjustable gas block, correct? Thanks.

[98Z5V]

The hole in your gas block is 0.125".  You're not drilling the gas block.  You're drilling the gas port in the barrel, itself.  The hole in the barrel.

You don't need to unbarrel the rifle to do this job.  Not necessary.  You don't need a drill press.  You do need to get the gas block out of the way, so you can drill the gas port. That doesn't mean that you even need to take the gas tube out of the gas block - you don't. 

You're drilling a larger hole, from a smaller hole, that is already there - your "drill guide" is already there.  You're only making a smaller hole, larger.  If you're skeptical or nervous about your abilities to perform this, then stop worrying.  Stick a 1/4" wooden dowel down the barrel, in case you think you'll hurt the rifling on the other side, once you break through.  If that's the main concern, then you're applying too much pressure on the drill.  If you do it right, that's not even necessary.

Use a variable speed drill (hand drill), you go slow, you lube the drill bit, and you apply light pressure to the drill - don't press hard, don't push it...  You just let the bit eat.  That's what it does.  Light pressure, slow-ish speed, and lube the bit.  It'll be done before you know it. That 1/4" woden dowel is completely optional, and should not be necessary.  If it freaks you out, though, put it in there before you drill.

Drill press = not needed.

 

Edited August 27, 2021 by 98Z5V

[thossoma@pm.me]

So the drill bits came today.  I got it drilled out and did some test firing.

The first thing I tested is I put 1 round in my magazine to see if it would lock back the bolt.  I was happy to see that it did lock back and ejected the shell!

I then put 3 rounds into the mag and fired again,

Not the outcome I was hoping for this time around.  It failed to eject the shell and jammed the next round into it.  I tried this a few more times and received the same results about 80 percent of the time.  There were a few times where it did eject the shell correctly and a few where it almost ejected it.

I then decided to try some steel ammo that I had and it actually performed better then the brass surprisingly.  I would say that it worked correctly about 75% of the time and only jammed a few times. It seemed like my ejector grabbed the steel better for some reason.

 

So I'm open for some ideas on what to try next.  I will say that I probably should have taken lube up with me when I went shooting, so that is what I will do next time.  I did just freshly lube it up before I went shooting though.

The first picture was the most common outcome for the brass.  The ammo I used...

[thossoma@pm.me]

Another note, I am able to eject a round every time manually using the charging handle.

[DNP]

Carrier looks a little dry. Get that thing soaking wet for a while while you get her broken in. It’ll take a handful of rounds to seal everything up again, but you should be having better luck than that. Something else is up. How many rounds (roughly) did you put through it on this trip?

[thossoma@pm.me]

I put about 30 rounds through this trip.  Should I just use something like REM OIL while breaking her in?  And should I be spraying it into where the cartridge seats into the barrel and all over the BCG?