I have many .223 semi-auto rifles and have no problems at all with the standard dies. I would go out and get a case length gauge and set the dies to minimum on the gauge. I don't have a problem with it as long as I set the dies up properly for the semi rifles. Now I forgot that when reloading for my .308 CMMG Mk3 .308, and loaded about 400rds that wouldn't chamber. They were too long. I resized the loaded ammo with a shoulder bump die and this time I remembered to use a case length gauge to set the die. It worked out just fine.