Well I found out today that the ammo I reloaded many years ago for my mini14 won't chamber in a tight chambered AR. Good thing I only sold 0 rounds of my factory ammo so far. And I was this close to selling the mini14. To try and compensate for the mini14s f'ed up head spacing I loaded the ammo to fill the void. Yeah bad plan. I should have set the dies up with go, no-go gauges. Oh well. But that was 20 years ago and I didn't know about go, no-go gauges. But I know that if a round will go into battery on my FN upper it will chamber in any 5.56 or 223 gun.