I also just picked up a SIG556 and I'm about to start giving it a workout to see how it handles.
USSA-1

Good shooting with the Sig. 556. I have run mine hard. I'm sure you'll run yours harder. (I'm a softy)

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Did have a squib round earlier this year, (previous post), NOT the Sig's fault. Did some barrel damage.
Sig made it right anyway, and it hasn't missed a beat since.
If you get the chance to try Wolf ammo, let me know how yours did, mine can be finicky with Wolf, but nothing else.