I'm getting reasonably consistent half-MOA groups with FGMM out of my LMT MRP, and thus far the only cleaning I've done is to de-gunk the receiver and bolt area after shooting it suppressed. It's a 5.56 chamber (possibly custom dimensions) not Wylde though. It's on about 500 rounds, and thus far nothing but bullets have passed down the barrel. Accuracy has neither improved nor worsened over that period.
Both "breaking in" and cleaning barrels for accuracy are myths in the context of field shooting. Even if they made a difference, and there's no evidence they do, it's clearly a much smaller difference than other issues that apply in the field (positional stability, wind, mirage, etc.)