I made it a point a long time ago when I noticed all the reloader ammo out there for sale and decided that I'd never buy or shoot ammo that comes in a plastic baggie with a sticky label.
I agree on case size differences. It's my understanding also that the SAAMI dimensions of the two are the same. The difference is in chamber dimensions for the 5.56 vs 223 (the 5.56 chamber has a different and slightly longer lede area for expansion). Also, the cases on the 5.56 are annealed...
It is scary to say the least. I had some old WWII 45 ball ammo that I'd started to dewat and did basically the same. Used a single stage arm and a deprimer attachment. Slow steady action - gentle.... But the first few were like with goggles and standback precaution....
Buy two of these - Woodworker's Supply | EBCO PRODUCTS® STEEL WORKBENCH LEGS and then a 4X8 sheet of good plywood (I used 7 ply sanded) and cut it lengthwise into two 2X8' sections and affix both sandwiched to the legs. Add 1X2" around the front three edges and a 1X6" back board. Run some 1X4s...
Back when (Before Ubama) I bought a bunch of Aguila Super Colibri....little 22 LRs with primer-only for plinking. Makes about as much noise as a regular 22LR using my AAC Element II can....
Could be a problem with extractor tensioning. I had a problem like that on one of my guns. Weigand Combat Handguns, Inc has an extractor tensioning insert for difference calibers that's used with your trigger pull gauge, AND they have an extractor tensioning tool that is used to adjust the...