Heartland Meats sirloin steaks

Dinner. Grilled two 4.5 oz. sirloin steaks. Good, a little chewy. Did I overcook them? I pulled them off at 140 degrees internal tempurature, just like Cook's Illustrated's grilling cookbook recommends for medium doneness.

The steaks were pretty cheap, though. I remember their filet mignons were good but very pricey. Maybe the NY strip is worth a try?