hey guys yet another shrike/mcr question, trying to tune my ROF using the info I've found on the forum, one thing I'm not quite sure of is which spring to use with the a5 buffer and tube... anyone have any feedback on the best springs to get to play with rof?  also are they carbine or rifle length springs the a5 system uses normally?

See my last post on this thread..currently, second to the last.
https://www.ar15.com/forums/Armory/Best-belt-fed-5-56-upper-/23-489762/

Thanks for the reply amphibian, I appreciate it. one question, does the tubbs flat wire 308 spring have more or less power than the original spring ares provided?

Check out this link by David Tubb: https://www.youtube.com/watch?v=8fMVZbrnvu8&t=153s
If you don't have the patience to watch the video, Joshv06 documented all the load sensor values:

A2 (old) - 7.6lb closed, 14.5lb open A2 (new) - 9.1lb closed, 16.7lb open
Tubb Flatwire - 10.5lb closed, 16.3lb open
Tubb .308 Flatwire - 13lb closed, 16.7lb open
SpringCo White ? (standard) - 8.3lb closed, 16.3lb open
SpringCo Red (extra) - 10.5lb closed, 18.4lb open
SpringCo Orange (increased) - 13.9lb closed, 24.8lb open

Note that all those values were obtained by shoving those springs into a CARBINE length buffer tube in the video link above.

Notice how there is only 3.7 lbs difference between the BCG being open or closed on the 308 Tubb spring....this equates to a smoother operation and slower RoF.

The Ares spring is not the same but similar to the Springco Orange spring.  So it will have more force to strip rounds off the belt but will also have a higher RoF.

I have never resorted to lubing or stretching links for my Shrike.  However, I have noticed that all the non-domestic 223/556 I have inserted into links takes more force than does LC or other American made 223/556 ammo.  I pretty much just run M193 or M855.

I think if you plan on running foreign made ammo then you may be better off sticking to the Ares spring.

Also mentioned in the other thread, while I've never had to do any tweaking with my Shrike, I did have a failure on my bolt carrier where the impact lug sheared off.  I never went heavier than an H2 buffer (4.5 oz) at that time.

I know some people run the MGI buffer with the Shrike which is 6.8 oz.  I personally would never do that after having a carrier fail on me with the 4.5 oz H2 buffer.

I am now running the Blitzkrieg/Kynshot 9mm buffer which is 5.9 oz....yes, heavier than the 4.5 oz H2 but I believe that the hydraulic action of this buffer absorbs some of the shock of the initial recoil impulse...
Remember that in all these 'front piston' systems that when you add more weight to the carrier or buffer that the impact lug of the carrier and op rod is going to take more abuse.

I've bent op rods of various piston uppers in heavy full auto and like previously mentioned sheared the impact lug off the Shrike.

With the 'stationary piston' of the standard AR gas system, if you go too heavy on the buffer, you aren't going to break anything.  Worst case is it just won't cycle.