Ye ole' cycling issue...

[98Z5V]

Just got off the phone with Leapers/UTG.  Asked the question - they only make ONE carbine receiver extension, just like I suspected. All these companies that say this is for "AR-10" are incorrect, because it certainly won't fit AR-10 Carbine recoil parts, and function. Will not. It will work with DPMS-based LR-308-type recoil parts, and that's the weird spring that nobody can get right, besides Sprinco and Wolff, and the 2.500" shorty 308 buffers.  Talked to the LE/MIL rep there about this very thing.  They make ONE carbine receiver extension, and it's for the AR15-specs.

Now, here's a pic of a bolt "locked back" on an empty MagPul LR-20 P-Mag, in an Aero Precision M5 upper and lower.  It's a D Wilson 308 BCG.  Receiver extension is DSG Arms mil-spec AR15 receiver extension.  Buffer spring is a polished DPMS LR-308 buffer spring.  Buffer is a regular AR15 Carbine buffer (3.0 oz, 3.250" long).  At first, it wanted to catch, but would slip off, and the empty mag is what's forcing the bolt catch up.   It wouldn't stay, on it's own. If I manually hold that bolt stop in, and ease the BCG there, the bolt stop catches the BCG body, and it's nowhere near close enough to catch the face of the bolt.

 

That receiver extension has an internal depth of 7.000".  

 

 

 

So, OP, please confirm the internal depth of your receiver extension, buffer and spring removed.  A tape measure is more then sufficient for a close-enough reading.  Just insert until it bottoms, and make the reading at the top of the receiver extension where it meets the lower receiver.  It's 7.000", and it'snot7 5/8", which is what you need to run the Armalite AR-10 Carbine Recoil System. 

The guy at UTG hooked me up with a permanent 25% of mil discount, too.  

Edited July 26, 2018 by 98Z5V

[98Z5V]

23 hours ago, D.R.D. said:

It is 7 5/8" I researched before I purchased it, then measured it.  It was made specifically for .308.  Yes, the bolt locks back, no problem.  

 

I'm waiting on the confirmation of these statements, collectively.  Unpossible.

This is your link to the product, that you posted:

https://www.opticsplanet.com/leapers-utg-pro-6-position-mil-spec-extension-tube-for-308.html

Nowhere in there does it list the internal length specs, or any length specs. The phonecall I had with them today verified (to me) that they only make one receiver extension.

In that, you never measured it when you got it. There's no way you did.  You relied on an ad from a company, and you assumed that it was right for you - and you didn't verify it.

You can fix your cycling issue - whether you made that thing lock back or not, by hand, my pics above show how that happened... You can fix this with one of three specific parts. 

1. Armalite AR-10 Carbine receiver extension, Armalite part # 10207025

2. VLTOR RE-10/A5SR; their 6-position receiver extension, 7 5/8" internal depth. 

https://www.vltor.com/shop/featured/re-10a5sr-a5-receiver-extension/

"The RE-10/A5SR Receiver Extension is a 6-position receiver extension designed to work with the VLTOR A5 buffer system.

This receiver extension is designed to work with Mil-Spec dimensioned M4/AR-15 type collapsible stocks. It also can be utilized as a replacement receiver extension for the AR-10 rifle."

3.  VLTOR RE-A5; their 7-position receiver extension, 7 5/8" internal depth.

https://www.vltor.com/shop/ar/re-a5-a5-receiver-extension/

"The RE-A5 Receiver Extension is a 7-position receiver extension tube designed to work with the VLTOR A5 buffer system.

This receiver extension is slightly longer than the traditional M4 receiver extension and is designed to work with Mil-Spec dimensioned M4/AR-15 type collapsible stocks.

This receiver extension tube can also can be utilized as a replacement receiver extension for the AR-10 rifle. Please email TechSupport@Vltor.com for additional information."

There are zero other products on the market that are confirmed to fix your situation. Zero.  There are no guaranteed solutions, besides those three that I just gave you. None.

You can roll the dice, gamble on whatever you want to gamble on, waste your money - and come back here and ask us how to fix it. And we'll have solutions...

But any one of those three will solve the problem, I guarantee that.

Edited July 26, 2018 by 98Z5V

[suzukiray]

This is an outside possibility but it DID happen to me once with a new build. First time out, first shot BANG, wouldn't chamber the next round. Manually chambered another, BANG, wouldn't chamber another round.

Long story short, and the ONLY time I've ever seen it, it had sheared the roll pin in the gas block holding the gas tube. I changed it right there and never another issue.

[D.R.D.]

This one?   https://www.midwayusa.com/product/1003409554/vltor-a5-recoil-system-carbine-receiver-extension-buffer-tube-7-position-mil-spec-diameter-ar-15-aluminum-black

I did in fact measure it when I first received it - but I only measured the exterior length, and compared it to a AR15 receiver extension tube.  I didn't measure the internal depth.  Figured I was good to go, especially when it seemed to lock back when built.  

What about dropping in one of these:  http://heavybuffers.com/car10xh.html  Would I be able to use my Armalite spring, or have to use the Heavy Buffer's spring?

 

 

[98Z5V]

2 hours ago, D.R.D. said:

This one?   https://www.midwayusa.com/product/1003409554/vltor-a5-recoil-system-carbine-receiver-extension-buffer-tube-7-position-mil-spec-diameter-ar-15-aluminum-black

That's what you need to fix what you currently have.

[D.R.D.]

Ok, so here's what I've got.

Bolt seems to go all the way back, mag & bolt catches engage properly when manually pulled back. 

Check out the gas tube position.

External length of the tube is just shy of 8"

Internal length seems to come in at 7 1/4"

What about dropping in one of these:  http://heavybuffers.com/car10xh.html  Would I be able to use my Armalite spring, or have to use the Heavy Buffer's spring?

Aren't there slightly shorter springs that I could use instead of the current one to solve the same issues?

[98Z5V]

That certainly doesn't look like a receiver extension that is 7 5/8"-ish internal depth.

You are aware of this chart from Slash, I'd hope:

Click it to make it bigger.  That buffer you are linking is 2.500" long.  If you run that with your (now fixed) recoil system, you will crash the hell out of your BCG into your lower receiver.

The cycling issues you had before were from a wrong-combination of components.  The buffer was right.  The Spring was right.  The receiver extension had a 7.000" internal depth.  THAT was the problem.  You need to get one of the receiver extensions I told you about, above, further up in the thread, to correct this issue.

I can tell you this - a 7.000" internal depth extension, a 2.500" buffer, and the EA1095 spring - doesn't work too well. I don't know where you found en extension that looks to be 7.25"... Just get the correct extension, and you'll have a great recoil system.  Armalite or VLTOR, pick it.  Nobody else makes it. Nobody.

Quote

Yes, the Armalite 

H3 buffer and the EA1095 spring in a UTG PRO tube

Edited July 28, 2018 by 98Z5V

[survivalshop]

Or get a DPMS 308 Buffer & Spring & leave the Receiver Extension in place .  

[98Z5V]

1 hour ago, survivalshop said:

Or get a DPMS 308 Buffer & Spring & leave the Receiver Extension in place .  

You'll need to find a 2.500" buffer that weighs about 5.4oz, don't just use a DPMS LR308 buffer - it's to light.  That buffer from Slash would do it.

Where you're at right now with it - H3 buffer + EA1095 spring, the cheaper route is to get the correct extension for those parts.

[survivalshop]

7 hours ago, 98Z5V said:

You'll need to find a 2.500" buffer that weighs about 5.4oz, don't just use a DPMS LR308 buffer - it's to light.  That buffer from Slash would do it.

Where you're at right now with it - H3 buffer + EA1095 spring, the cheaper route is to get the correct extension for those parts.

Why is it too light ?  Its matched with a stronger Spring , its just a different system , works fine in tens of thousands of DPMS LR Rifles ., just like the Armalite system does , just two ways of going at it . They are both fine , when the correct components are used .

DPMS 308 Carbine Buffer - $ 28.95 , 308 Carbine Buffer Spring - $ 5.99 , my math is not good , but thats around $ 35 .& you don't have to disassemble any thing , just pop the Buffer & Spring out . Armalite has their Buffer system for $ 55 , which does include the Receiver Extension , Buffer & Spring , End plate & Castile Nut , but all you need it the Receiver Extension , Ok I'm sure they are in stock somewhere .

[98Z5V]

3 hours ago, survivalshop said:

Why is it too light ?  Its matched with a stronger Spring , its just a different system , works fine in tens of thousands of DPMS LR Rifles ., just like the Armalite system does , just two ways of going at it . They are both fine , when the correct components are used .

DPMS 308 Carbine Buffer - $ 28.95 , 308 Carbine Buffer Spring - $ 5.99 , my math is not good , but thats around $ 35 .& you don't have to disassemble any thing , just pop the Buffer & Spring out . Armalite has their Buffer system for $ 55 , which does include the Receiver Extension , Buffer & Spring , End plate & Castile Nut , but all you need it the Receiver Extension , Ok I'm sure they are in stock somewhere .

What was the design of the rifle?  5.4oz rifle buffer.  How did they shrink that 5.200" rifle buffer down to a 3.250" buffer, and still get it at the same weight?

Tungsten.

Don't argue with me - tell Eugene Stoner he's the one that's wrong... I didn't invent it, here.  I just make sure people can run it, and run it well.

Eugene Stoner = John Browning = God.  They are all equal in my eyes.  Refuse it if you want. 

Edited July 30, 2018 by 98Z5V

[survivalshop]

4 hours ago, 98Z5V said:

What was the design of the rifle?  5.4oz rifle buffer.  How did they shrink that 5.200" rifle buffer down to a 3.250" buffer, and still get it at the same weight?

Tungsten.

Don't argue with me - tell Eugene Stoner he's the one that's wrong... I didn't invent it, here.  I just make sure people can run it, and run it well.

Eugene Stoner = John Browning = God.  They are all equal in my eyes.  Refuse it if you want. 

Where is it that I said Mr Stoner was wrong ?  Just more then one way to accomplish proper operation . There is a lot that goes into what weight  Spring  & there lengths is correct for proper function of a DI operated Action , its a balance of components . I never said there is one way better then the other , you are , I just pointed out , it might be an easier way to get the rifle with the correct components to see if it takes care of the issue he is having . I don't care one way or the other which system he choses , I'm not an Armalite pusher or a DPMS , I don't bow to one or the other , they both work , thats plain & the amount of DPMS LR 308 type Rifles out there prove it , I would be safe to say , thousands more then AR 10 in the same configuration ( Carbine ) , so to sit here & say that the Armalite system is superior to the DPMS system , is not proven by any facts .

 That is Stoners design & DPMS is DPMS's design , you cant say they don't work , you can only say you like one or the other . ?

[D.R.D.]

I spoke with Clint at Heavy Buffers as well.  He agrees with what 98Z5V wrote.  Given the recoil of 168-178gr loads, and an effective break, I wouldn't want to go lighter than 5.4 oz. on that buffer.  So, I ordered the Vltor extension.  It will be in next week.

 

 

[98Z5V]

7 hours ago, survivalshop said:

Where is it that I said Mr Stoner was wrong ? 

Ah, you didn't say that; I didn't mean to imply that. 

The entire operating system (gas system, recoil system, BCG weight, etc.) was designed with the buffer weight of 5.4oz because it worked.

Somewhere along the way, buffers got lighter and springs changed, and not necessarily for the better.  Do they work?  Yeah, they'll function.  Are they ideal?  Usually not.  I think that the primary changes were made based on budget - looking at the DPMS LR beginning.  Would you buy the parts from Armalite, or make your own, and make them different so you don't get your pans sued off?  "Sure, grab that AR15 receiver extension and let's make that thing work..."

The specialty springs are the icing on the cake (Tubb flat wire, Sprinco Orange, Wolff XP Springs, and I'm sure more).  Then again, even using one of those is "fixing the system" when it wasn't ideal, no?

2 hours ago, D.R.D. said:

I spoke with Clint at Heavy Buffers as well. 

I wish he came around more - he's a goldmine of information.  And a good guy. 

Edited July 30, 2018 by 98Z5V

[survivalshop]

Most say a 16" 308AR barrel with a rifle length gas system will not work also.

Your right , DPMS went about the Buffer system a different way to get around Armalites Patent or their threat of a law suit. I'm also sure Clint knows a lot , but he is also selling those heavy Buffers , what did you expect him to say !

[blue109]

No issue with DPMS buffers/springs in milspec extensions...but then again I dont torque or stake castle nuts either ?

[D.R.D.]

Alright, so I got the Vltor A5 extended (7 5/8") tube.  It turned out it was only 1/8" longer than the UTG Pro I had on before.

Now this is happening.  It's not even ejecting.  I even opened up the gas block all the way.  No dice.  Tried 5 different mags.  Multiple settings withe the gas block too.  No cycling.   Considering the heavier buffer to slow the cycling, but I can't help feeling like even though the bolt can lock back, there's not enough room in that tube for the H3 buffer &  EA1095 spring.   So even if I put in the XH Carbine Buffer, it's still the same 3.250" as the H3.

One additional things I noticed:  If I insert a mag loaded with two rounds, chamber a round, then pull back the charging handle a 1/2" to check that the round was chambered, the next round won't fire - as if the bolt won't go all the way forward again and the firing pin doesn't connect with the primer.  I simply hear a click.  

This whole thing is frustrating, especially since it's shooting sub MOA.  Might as well have a bolt-gun at this point. LOL!

[D.R.D.]

So then, I guess I wondering if there is any risk to doing nay damage to the receiver or BCG if I put this:

https://dsgarms.com/armec0040  with the H3 Buffer

or this:

https://www.kakindustry.com/lr308-carbine-buffer-heavy with the  EA1095 spring

or the shorter spring and .308 carbine buffer?

...all would be running in the Vltor A5 7 5/8" tube.

[98Z5V]

5 hours ago, D.R.D. said:

Alright, so I got the Vltor A5 extended (7 5/8") tube.  It turned out it was only 1/8" longer than the UTG Pro I had on before.

Now this is happening.  It's not even ejecting.  I even opened up the gas block all the way.  No dice.  Tried 5 different mags.  Multiple settings withe the gas block too.  No cycling.   Considering the heavier buffer to slow the cycling, but I can't help feeling like even though the bolt can lock back, there's not enough room in that tube for the H3 buffer &  EA1095 spring.   So even if I put in the XH Carbine Buffer, it's still the same 3.250" as the H3.

One additional things I noticed:  If I insert a mag loaded with two rounds, chamber a round, then pull back the charging handle a 1/2" to check that the round was chambered, the next round won't fire - as if the bolt won't go all the way forward again and the firing pin doesn't connect with the primer.  I simply hear a click.  

This whole thing is frustrating, especially since it's shooting sub MOA.  Might as well have a bolt-gun at this point. LOL!

 

Is this thing lubed, heavily?

The two things I bolded above.  That's not even possible.  If you have the correct VLTOR tube(s) - there are two you can get, and one that's wrong. 

The UTG Pro you bought before was 7" internal depth, and I verified that with them on the phone - it's all they make.  That's AR15 Carbine Receiver Extension, right there, only.

It's not possible for you to have a VLTOR A5 tube that's only 1/8" more in internal depth.  Something bad is going on here.

The two VLTORs that with work correctly are the VLTOR RE-10/A5SR.  That's a six-position tube.  Then, you can use the VLTOR RE-A5. That's a seven-position tube. Which one did you buy, directly by model number?

 

[D.R.D.]

This is the one I ordered:  Product #: 348370

https://www.midwayusa.com/product/348370/vltor-a5-recoil-system-carbine-receiver-extension-buffer-tube-7-position-mil-spec-diameter-ar-15-aluminum-black?utm_medium=email&utm_source=service&utm_campaign=order-confirmation&utm_content=product-description-link

 

 

[D.R.D.]

The attached image is of the UTG Pro.  I measured the Vltor side-by-side before putting it on, and it was only ~5/8" deeper.  

Both are very well lubed, as is the spring.

[98Z5V]

Then you need to re-measure that internal depth.  It's not 1/8" longer than a 7" tube.

[98Z5V]

1 minute ago, D.R.D. said:

The attached image is of the UTG Pro.  I measured the Vltor side-by-side before putting it on, and it was only ~5/8" deeper.  

Both are very well lubed, as is the spring.

What's the story here?  1/8" longer, 5/8" longer?...

[D.R.D.]

You're looking at the UTG.  Regardless what they told you on the phone, you can plainly see it's 7 11/16" internal depth.

The Vltor measured a tiny bit over 7 3/4"

 

[98Z5V]

Good luck, man.  Call UTG if you don't believe me. Do you even know what part you got in the mail, from a 3rd party vendor?

I hope you get this sorted out, i really do. I hate trying to "beg" information out of people.  Hope you figure it out. 

Edited August 23, 2018 by 98Z5V