Looking to get a belt fed 5.56 upper to run on some post sample lowers. Price isn't really a major factor but reliability is. I'd rather not have to tweak it 87 times to run correctly.

Um, my understanding is that there is only one, the ares/fightlite.

which may or may not require tweeking, but I would give a gen 6 a try with the metal insert

I've got an old circa 2004 original Shrike with the modified steel 249 feed tray and other than the initial break in and had to do no tweaking.

and I destroyed a gen 5 receiver and had to get a replacement.

There are more threads on shrikes not working than working.

I think the Fightlite MCR060 is pretty much the only option worth considering. They have come a long way as far as quality and reliability goes, might also be why they rebranded (formerly Ares Shrike).
I would recommend picking up the latest, Gen 6 upper. I intend to pick one up eventually, its just not at the top of my priority list at the moment.
https://dealernfa.com/fightlite-mcr060/

You could do a Valkyrie belt fed but it requires cutting the lower, it doesn't easily switch between belt and mag fed, and does not have a removable barrel.

Also, if you have access to post sample maybe consider a M249/MK46? You will have $4k invested in a MCR upper, for around $8k you can have a post sample M249

Hoping Freedom Ordnance will come out with a 556 belt fed...

Actually got mine in 2006.  Here is a video of the day I got it.  
https://www.youtube.com/watch?v=RpeF89tq7-Q

I'm well aware of more post of them not working.  As their are always more posts about bad vs good news.
I guess myself and my friend in the video that passed away were lucky as we both didn't do any tinkering.  We were one of the first few so maybe ours were hand tuned.  I don't know.
After my first 20K or so rounds the impact lug of my carrier did shear off.  Ares did replace at no cost to me.  I never went heavier than an H2 buffer either.

That is the only part that broke on mine but as to the original posters question, I had to do no tweaking.

This is sound advice if you can get a demo letter.

Could also consider a closed bolt MGA m249 clone that uses a HK fcg, use a post sample HK trigger box. Or a semiauto FN 249S with a registered bolt carrier.

Are you running 855 or 193 ammo in that vid?

Does anyone have one on a Olympic Arms PAWS Lower?

Was wondering if there are any fit issues with the FrightLite MCR060?

Also how does it run with the A5 buffer system or must you use the carbine tube set up?

I've been playing around with the 9mm CMMG Guard's radially delayed blowback setup trying to get it to run as smooth as possible and comparing to an MP5.  Both in full auto.
The smoothest configuration I've found was: A5 tube + hydraulic '9mm' Blitzkrieg/Kynshot buffer + 556 Tubb flat wire spring.
That '9mm' buffer happens to be the same length compressed as an A5 buffer so I've been running this in all my other center fire caliber configurations.  Works with them all except for 7.62x39 for some reason.
I have some pictures and info on this here: http://c3junkie.com/?page_id=538

For the Shrike, I use: A5 tube + hydraulic '9mm' Blitzkrieg/Kynshot buffer + 308 Tubb flat wire spring
This made a huge difference, I can now pull singles with the Shrike and it smoothed it out.
Here is some test data for my Shrike and this buffer configuration:
12.5"  M855 630 RPM
16" barrel M855 693 RPM16" barrel M193 661 RPM

I have two Olympic receivers of similar vintage to the Oly/PAWs receivers.

My Shrike would not fit on either of them initially.  One of the receivers made a trip through M60Joe and US Anodizing and now the Shrike fits that receiver.

The other Oly I have pretty much ever other upper fits without much issue but the Shrike was a no-go.

I don't shoot my Shrike on either Oly though and it lives in a custom magwell-less / SAW box only receiver I made and is paired up with one of the couple lighting links I have.

I run mine with MGI Rate Reducing Buffer and a Sprinco "Red" enhanced spring.    I tried one of the kynshot hydraulics as well as a colt hydraulic and didn't have success with either.

The kyshot I had reliability issue with a failure to strip rounds and short stroking.  I even cut the buffers hydraulic piston down shorter and TIG welded the end plate back onto the piston so the compression was shorter and still had no luck.

The Colt unit  broke and spewed its guts and oil out after a couple belts.   I have a second NIB Colt hydraulic buffer but its just a conversation piece at this point.

To be fair the MGI nested springs that go between the sliding weights disintigrated in a couple thousand rounds as well, but I replaced the springs with stronger spring and its been running for years ever since.

I am tempted to go back and try another hydraulic setup, but mine runs about 800ish RPM and has good reliability so it just never moved to the top of the list to mess with.

can you give me more details please?

The MGI buffer is mechanical. Instead of thin rubber discs between the tungsten weights there are holes drilled into the tungsten weights with springs inside the holes. So when the buffer starts to go back, initially the carrier only needs to move the buffer casing and on tungsten weight. As the springs inside compress, another tungsten weight is moved. As I recall the MGI buffer is 7.2 oz.  But the carrier doesn't have to start all the mass to move at once.

Scott

There are nested spring between the three traditional tungsten weights inside the buffer.  In my estimation the MGI OEM springs were pretty light for the duty they are asked to perform and ultimately died in a couple thousand rounds, resulting in the tungsten weights inside the buffer body locking up with little bits of broken spring bits.

The idea of the springs is to keep the tungsten weights at the back of the buffer and also keep the bumper extended.  When the buffer starts to move rearward the weights slowly slide forward compressing the springs and smoothing the recoil curve.  Then when the buffer hits the back of the buffer tube the extended recoil bumped compresses the springs (softening the recoil) and also launches the weights forward which in theory also reduces the rearward recoil.

When the bolt slams home the buffer weights are then again allowed to compress the springs and eventually bottom out keeping bolt bounce in check as they would in a traditional buffer.

Here is a pic of an MGI unit disassembled.

https://www.ar15.com/forums/ar-15/L-A-R-B-Linear-Alignment-Recoil-Buffer-Thoughts/118-716043/&page=4   <----this guy had a MGI spring failure as well.

You can see in the pic how small and thin the wire diameter of the nested springs are.



My personal take is that the "recoil reducing" properties are somewhat dubious in effectiveness, but there is a marginal rate reducing property associated with this arrangement beyond the increase in buffer mass.

For me I went with the MGI for the increased buffer mass and the hope to minimize the chance of bolt carrier key impact damage that seemed prevalent to my Shrike's vintage with folks who ran heavy buffers.  The hope being the spring nested weights would reduce the impact spike on the carrier key vs. just a standard heavy buffer and which seems to have worked out fine for me thus far.

Ultimately, I started getting classic bolt bounce symptoms at some point and when I took the gun apart it was obvious that the buffer wasnt working properly anymore and had no anti-bounce properties left given the weights were locked/frozen inside the buffer  body.

I took it apart, cleaned out all the spring bits, and then replaced the nested springs with some more robust springs that came out of one of those "misc spring multi-packs" from home depot.  I probably ended up doubling the spring wire diameter in the process.

Ever since the spring swap the buffer has run without issues for years.

perfect, thanks!

I had the spring break in one of my MGI buffers also:


I was using mine for just the mass aspect also but never in the Shrike.

I never went heavier than an H2 (4.5 oz) with the Shrike and had the impact lug of my carrier get sheared off.  Geoff (inventor of the Shrike) warned me about going too heavy as it puts more stress on the impact lug and op rod.  He told me mine broke due to bad heat treat.  I know they recommend the H3 and other have had success with much heavier buffers but I've just always been leery of it.

As mentioned previously, I'm using the 9mm Hydraulic that is 5.8oz but I think the Hydraulic action is buffering the shock vs a mechanical weight buffer.
With the setup mentioned previously, my Shrike is now a dream to shoot in the 600's and pulling singles easily.

You're running a buffer designed for 9mm on your shrike/MCR?

I've got more details at this link: http://c3junkie.com/?page_id=430
comparing various buffers.

Tuning data here: http://c3junkie.com/?page_id=654

Thanks.  I've got an MCR that's having trouble feeding when using the belt.  Is that most likely a buffer weight/spring problem?  I've got the Mark Genovesse piece in there and I'm using M855.  Mags run flawlessly.  Just feeding issues with the belt.

When you say M855, are you referring to Lake City M885 not some imported M855 right?
I've noticed that some imported brass cased ammo is a little tighter in the links than domestic brass cased ammo which then in turn requires more force to strip rounds off the links.
I have an early Shrike. Got mine in Oct 2006: https://www.youtube.com/watch?v=RpeF89tq7-Q
Mine has the modified M249 SAW feed tray.  I've never resorted to lubing links or stretching them either but I also only use brass cased ammo.  I don't use Mark's feed ramp either.  
All that said, I've never had feeding issues with mine.  
I did have a bolt carrier shear off on me after a lot of rounds and I never went heavier than an H2 buffer back then.  
They replaced my carrier and said mine had a bad heat treat.
The owner of Ares reminded me that when you go heavy on the buffer (on a piston system), you are putting more stress on the op rod and impact lug on the carrier so I have always been leery of going heavier than an H2 (4.5 oz)....although mine probably was just a bad heat treat as you see many posts of people using MGI buffers that are 6.8 oz.

While the hydraulic is heavier than an H2, I personally think that the hydraulic action is absorbing some shock.

I've always wanted my Shrike to run smoother and slower and using my combination of an A5 buffer tube + 9mm Hydraulic Kynshot (A5 length buffer) + 308 flat spring gets me in the 600's and is smooth.

I don't know what buffer weight/spring you are using now and I don't know what is going on with your feeding issue.  In the event that your setup is cycling too fast, my combo may work for you since it is certainly slower but I have no idea what the root cause of your feeding issue without seeing it first hand.
Me personally, if you cannot get it to run with the Ares / Fightlight recommended buffer/spring/ammo, you need to work that out with them.  Once you know it is working with their 'validated' configuration then deviate to something more of your liking in regards to cyclic rate and smoothness.

I'm using Lake City and the buffer spring was supplied by Ares.  Offhand, not sure about the buffer.

Recently I bought some dry lube (haven't used it yet) and am looking into getting a link stretcher.

IME, you need at least an H2 (4.5 oz) for the Shrike to run reliably on belts.  
When Gen is your MCR?

I personally think you shouldn't need a link stretcher, I've never used one....especially if you are running LC M855.

I'll check the buffer weight when I get home.

Not sure which gen.  Bought it right before they changed from Ares to Fightlite.

I really appreciate your help.

It's rifle-length and I have a Spike's T-2 buffer.

As a test I hand-cycled about 10 rounds.  Pulling the handle all the way to the rear and letting it go consistently produced FTFs.  It took a second pull to the rear to get the ammo to chamber.

What is rifle length? Your spring? Buffer tube?
The Spikes T2 uses tungsten powder which may be a bit softer in its dead blow hammer effect than an H2 that uses solid weights.  I would try a real H2 or H3

It's got an Ace Skeleton stock.  Buffer tube came with it.  The spring is what Ares supplied.  And there's a spacer for rifle-length stocks that they also supplied.  Apparently almost everyone but me runs a collapsible.

I'll try a different buffer.  Seems like a heavier spring might also be in order.

@amphibian

After realizing I had a 5oz buffer (well, 4.9oz) and some different springs in the spares parts bin, I did some testing.  The heavier buffer didn't do much.  The carbine springs on hand (Sprinco blue & red, and a .308 orange) were all shorter and less coils than the factory spring.  The one rifle-length spring (Sprinco M16 green) on hand is 5-6 coils longer than factory in it went.  Between the spring and the buffer it consistently hand-cycled the rounds in a 10 round test.

Guess it's time to get 'er back out to the range.  It doesn't seem so stiff that FTEs should be an issue.  Knock on wood.

Posts like this are the reason that after 4 years I have still yet to pull the trigger on purchasing a MCR. I cant fathom spending $4-5k for a upper and only be able to run one specific type of ammo, or not cycling properly because you didn't use the EXACT spring and buffer combination. There is a reason why after a decade this upper still is not in service by any major militaries or government agencies. Very cool concept and allows lower tier MG owners to scratch the belt fed itch but sure as hell doesn't compare to an actually military grade belt fed.

Lately I have been thinking I would rather go with M27 IAR inspired build. Cheaper, more reliable, and no need to swap out springs, buffers, bolt catch.

I ended up buying the "latest gen" Fightlite upper last year. Haven't shot it yet but will try and put some rounds through it in the next couple weeks. I got a pallet of Magtech linked 55gr 5.56. Will be pretty upset if it doesnt function

Sorry for the crappy update but that's where I'm at now

To each their own.  It's not like I'm limited to one rifle.  Once it's running right it'll be money well spent.  If the rifle-length spring and a heavier buffer clear up the issues that's hardly a big deal in my book.

Sprinco Orange has quite a bit more stored energy even though it's shorter and has fewer coils.  It takes about 27lb to fully retract the Sprinco Orange spring in my (formerly) BumpSAW.

Thanks!  I'll make sure to take that one to the range next time in case the green spring doesn't do the trick.

What do you mean by you destroyed the receiver?

I'm so jealous of you guys that have working Shrikes!  Mine has been nothing but problems.  Got mine around 2009-2010 I recall.  Went through the suggested break-in and then it worked pretty good.  Over the years I have had sporadic success with mine.  No problem running mags but belts are a whole different issue!  Early on I was using .223 ammo as Ares wasn't pushing M855 which depending on the FUDDS running your range might not be allowed.  I get a belt to fire flawlessly and then the next belt jams.  All kinds of .223 & Prvi Partisan M193 with sporadic success.  Left it alone for years and then started a few months back as I am now belt-fed-LESS!  A belt of .223 runs and the next belt jams.  Ares now Fightlite advises me to use M855.  M855 ran a couple of belts perfect and then starting jamming again.  Using AE M855.  Had a few hundred AE 556 55 grainers and had some success for a few belts and then the jamming again.  Switched back to 62 grain M855 and sporadic success again.  Had it out a couple of days ago and run a 100 round belt of AE M855 out of a 100 round Nutsack and it ran perfect.  Grabbed a loose belt just shy of 100 rounds and let it hang and had 3 jams before I could finish the belt.  Ares/Fightlite states it is capable of firing with a 100 round belt hanging.  Not in my experience!  Loaded another 100 round give or take belt and fired it off RAMBO style with the belt laid across my arm and more jams.  Packed up after that out of frustration. I'm a pretty stubborn guy but I'm starting to give up on this thing!  With this experience I just can't justify spending the doe for a GEN 6....I am just not convinced and I have read the horror stories of owners and their experiences with CS.....

What buffer / spring are you running?
Sorry you have are having so many sporadic problems.  Is it lubed up?  Any wear marks on the carrier?

Your post reminded me I did a video of mine doing the 100 round belt hanging.  This was back in 2007 with my early Shrike.  
Just posted it up here:
Shrike 100 round hanging belt pull

Ares Defense supplied spring and whatever buffer Ares told me to use.  Maybe a Colt H3?  Oiled up, no unusual wear, Colt lower.  I thought I had it licked when I bought some Federal AE M855 but jams with that ammo also.....The only wear I see is on the feed-tray which as I am sure you know is aluminum and the links are steel.  I wonder who at Ares thought that was a good idea?

As mentioned mine is using a modified 249 SAW tray.  Later Ares wasnt able to acquire enough of them so starting doing them out of Aluminum that a lot of people bitched about them gouging.  Mark Genovese made a plastic/polymer feed ramp to fix it that got great reviews but sounds like he isn't making them anymore....I thought all the current FightLite models had steel trays now.

However, I'm not clear as to what kind of jam you are having.  Stovepipe?  Feeding?
How is your extractor and ejector spring?

You name the jam and I get them.  AND, have you priced a steel replacement feed-tray from Fightlite?  Extractor & spring fine and mostly feed issues not so much stove pipes.  Runs perfect with mags!  Naturally I bought this belt-fed to shoot belts.

Yeah...I know like $500...that is why a lot of people were using Mark's feed guide and not spending the crazy amount for the feed tray.
They used to do end of the year Christmas sales which included them but I don't recall getting the email last year.

I actually have 2 Shrike's.  I was one of the early depositors.  I got tired of waiting and got my money back and a local friend got his in one of the early batches and I bought his NIB from him.  
Later Ares, offered the original depositors intro pricing so I got a second one to use for spare parts and have never fired it.  It has the aluminum feed tray.  I'm tempted to shoot it to see if I run into any issues.
I'm fortunate that I've had no issues with mine other than the carrier shearing off which Ares said was due to a bad heat treat.  After break in, it has run 100%.

I know of two other local guys with them and theirs have also been 100%.

I envy you!  Those feed trays you speak of are not being made anymore and I didn't get a year-end sale invite either!  As far as I'm concerned, Ares/Fightlite should ship all owners a new steel feed-tray as a repair!!!

Wow that sucks you've had so much trouble, after break-in mine works great. I've got a shrike upper and an mcr, I only shoot the mcr though its like serial 450 or so just before the change to fightlite.

does the upper mess up the lowers ?

NO!  Just took my Shrike upper off my Colt M16A1 without any problems as I ran my rifle in it's original form without a hitch....

Don’t forget the spacer behind the buffer and buffer spring. Otherwise the carrier hits the receiver extension support of your lower. Ask me how I know....

a spacer ?

For using the Shrike's carbine buffer/spring setup in a rifle receiver extension. It just renders it the same length as a carbine receiver extension.

Ok never mind. It says the spacer goes in carbine extensions.

Yes.

https://fightlite.com/mcr-carbine-stock-spacer