Best Rifle Duo

I have been thinking about this for a while - which is the best rifle duo currently available? By duo I mean a 5.56x45 version and a 7.62x51 version (at least one smaller, the other bigger caliber) in a virtually identical platform…

KAC SR15 IWS and EMC?
LMT MRP and MWS?
FN SCAR 16S and 17S?
HK MR556 and MR762?
Colt 6920 and SP901?
Arsenal/SGL 5.45 and 7.62 AKs?
Any other combo…

Spooky

LMT is probably the most versatile with all the barrel combos you can imagine.

Any news on the Colt SP901 (7.62 NATO)?

I forgot about the Colt offering - I’ll add a 6920 and SP901 to the list…

I don’t know if or when it will be available but I would say the Scar 17s with the 5.56 conversion.