If it were ME.
I'd do in this order:
1.) Get out of the SCAR 5.56 and into a 7.62 one.
2.) Sell the SCAR, pick up an SLR-106FR and share ammo with your other 5.56 weapons (sounds like you have a few)
3.) Trade SCAR for an SGL-31 side-folder and buy a lot of ammo.