I've read that you should not crimp .223 because it can cause a pressure build up that will damage the upper receiver on an AR-15. I'm considering doing it because I'm having an issue with slightly over sized casing necks when I reload .223. It's become an issue because I'm finding that after case prep some of the necks are so over-sized that the bullet will actually drop all the way through the neck into the casing when I seat the bullet. Very messy, and even more annoying. Then I have a wasted casing that has a live primer in it. On that note, I'm afraid to run a casing that has a live primer through my decapper because I'm afraid it will go off. Is there any way to save a live primer in a bad casing? So back to my original question- can you safely put a mild crimp on a .223?