I did...look at the previous page of this thread: https://www.ar15.com/forums/industry/Bearing-Delay-Upper-Receiver-Assembly-updates-information-and-resources/817-303326/&page=4
You would have to ask MEAN if they will sell you a spare barrel or extension but doubt it.  Your end goal is do an SD build but they are already working with I think https://hitecarms.com  on a SD setup.  So they may want to do their own internal testing first.

Not fair to say that.  I'm on my 3rd ejector spring on my MEAN in less than 2000 rounds.  Nothing is perfect.  
I have stated many times that I was never impressed with the out of the box recoil impulse of the CMMG Banshee or Dissent.  Better than straight blowback but like 60% there compared to straight blowback but a tuned CMMG RDB can match the MP5 with a 'better' cyclic rate than the MP5.  Most people running CMMG's Banshee's don't care about tuning until they start to fail and most don't know what smooth is as they haven't shot anything better side by side.

The CMMG Dissent fixes the failing ejector spring problems since they finally went with a fixed ejector eliminating that from the maintenance schedule and point of failure.  I would be ecstatic if MEAN did the same.

Read the MEAN manual which clearly calls out wear item parts, like the ejector spring, ejector retention pin, extractor spring as well as the ball bearings.  
Nothing lasts for ever and it is to be expected for any delayed system where parts are impinging on each other.
My tuned hybrid Dissent has not missed a beat since I built it which uses a fixed ejector.  I run this full auto and suppressed with a tuneable full auto cyclic rate.
The CMMG delay comes from the angled lugs on the bolt and the lugs in the barrel extension which are standard.  Several people have made their own CMMG compatible barrels including myself.  
I have a custom stainless CMMG RDB barrel with over 50K rounds on it and there is no detectable wear on the extension and if there was some, I could swap it.  You can buy spare bolts and BCG's from CMMG.  Can't say the same for MEAN yet but yes, you can buy the lifters.  
Extra barrels are not yet available for the MEAN and now look at all the proprietary parts in the BCG for the MEAN.  
I would say my MEAN with the K lifter is slightly softer than my tuned hybrid CMMG Dissent but the ejector I have in there is fixed and will never fail and doesn't have a maintenance schedule that is clearly an advantage over the MEAN.

For me my order of preference 'today' is:
1.  My tuned hybrid CMMG Dissent with the fixed ejector and custom made carrier extension for tuning w/ buffers and springs as well as to trip the auto sear documented here: https://c3junkie.com/?page_id=1733
2.  MEAN Arms is only second since it still uses an ejector spring that is inline with the recoil impulse and I'm already on my 3rd one in under 2000 rounds.
3.  CMMG Banshee and deal with the ejector spring failures as well.

Now if we are talking semi auto only and not full auto like I want my preference would probably be for someone that didn't want to go with any custom parts
1.  JP-5
2.  CMMG Dissent  - I would move that to #1 if you are OK with custom parts or if you have a SBR lower since the JP-5 is using a proprietary upper/lower receiver length.


ETA...At last month's SMG match, I ran my hybrid CMMG Dissent which ran 100%.  2 guys brought their MEAN uppers.  Both had around 300 rounds on them before the match.  1 guy ran his for only 1 stage with no issues.  The other guy ran all 4 stages with his MEAN and it was a disaster.  I was the RO for him and saw several times where he had a live round facing back at him which was really weird as well as some FTE's.  

Well hell amphibian!!! Thanks, I had no idea there was an integral coming out. Looks like all I need is some patience and to shoot the CMMG until the extractor fails and then buy another mean arms uppers.

that plan works for me, time to sell off all the other crap I've accumulated for these builds.

CMMG's typically don't have EXTRACTOR failures...it is the EJECTOR SPRING that fails....
and again, the MEAN isn't immune either.  I'm on my 3rd EJECTOR SPRING on my MEAN in less than 2000 rounds of full auto / suppressed.

My hybrid Dissent build utilizes a fixed ejector which removes that point of failure.
I believe you are running full auto suppressed with a RLL?  I would wait till you have several thousand rounds through your MEAN before buying more...although, I'd be happy to sell you my MEAN upper if you want.

This past weekend Zack Smith won the PCC division at the Rio Salado 33rd Annual Spring Steel using the Bearing Delay system!

I appreciate your dedication Amphibian. You saved me a lot of headache and heartache, by explaining the short falls of both the Mean and CMMG RDB systems. I'm looking forward to your completed write up on your custom Dissent and will probably go that direction if it is possible for me. Right now I'm really liking my 90% set up with the 9mm RDB bolt and barrel, Tubbs 300blk flat wire spring, and 5007 Hydraulic buffer. I allowed my wife to shoot it so she could compare it to her blowback AR-V and she didn't want to give me my weapon back. It was really a night and day difference.

Shot the local steel challenge match in PCC optic division with the Mean upper. There were 64 shooters and the top ten overall were dominated by the 22LR classes. Including my 10th place finish in rimfire rifle optic class. At 73 I don't expect to beat those way younger. However, with the Mean I was able to take 11th place only slightly slower than my 22LR  performance. Used the Endomags downloaded to 28 rounds with no problems.

I have abandoned using Glock mags at the local subgun match. Just don't get reliability when it was not engineered for Glock. 28 rounds would put me at a disadvantage against higher capacity guns so I am waiting for the 40 round Exomags. After testing I will post my results.

After a lot of back and forth with Amphibian on his current CMMG project I have decided to stick with my Mean upper. His ability to re-engineer has me in awe but I think we have different goals in what we want from FA fire as I do not shoot suppressed for example.

While I do enjoy running suppressed like 90% of the time.  I built several of my hybrid Dissent fixed ejector builds for SMG competitors that only like to shoot un-suppressed.  A couple of my friends ran my builds 100% in the past few matches.  I think unsuppressed is easier to deal with as it doesn't get fouled up as fast as suppressed does.  Although I ran my last match 100% switching to grease vs oil with zero cleaning and 100% suppressed.  BTW, I am running Colt mags in my hybrid Dissent full auto build now as it runs the flat point bullets I got from American Reloading reliably while my Endomags, Glock and Scorpion mag setups do not run them reliably.

There was a slight chance the 40 round Exomags would arrive in time for our monthly Subgun match tomorrow June 9th. That is not the case as I was informed some additional tweaks need to be made to the molds so there will be an additional delay. With the extreme high temperatures in the Nevada desert our monthly Subgun match is suspended for the months of July and August. Hoping that I will have the 40 round Exomags in time for the September match.

It seems I missed the pre-order deadline to qualify to have my Exomag order doubled. Would have placed it earlier if I had known.

@tt350z
@amphibian
@subgunner

Any updates on your MEAN experience?

I sold mine with a $500 loss.  If I had known they were going to release the production model with the same spring loaded ejector as the CMMG Banshee I wouldn't have gotten it.  The earlier prototype that they had at a previous Shot Shot didn't use the same spring loaded ejector like the production model and was hoping that it would be that way.  I should have waited to see what it really looked like.  I did give it a chance though and after swapping ejector spring 3 times in under 1200 rounds, I was done.  

I am not the only one either, I know two other people with the same issues.  However we are all running full auto if that makes a difference.  

Now if they release a 'Gen2' with a fixed ejector, I would give it a try as it was smooth when it worked.

@tortilla-flats

Still running perfectly. Zero malfunctions. Zero parts replaced. It’s been loaned to new shooters so they have something to compete with. Maintenance has just been some lube once in a while. I haven’t wiped down the BCG in like 2k rounds. Mines only used for USPSA/multi-gun. No full auto or suppressed.

Which upper are you using? Could you put a link in for slow types like me

@towerofpower94

MEAN Arms bearing delay upper

Thank you, sir