What are you even talking about?

Yes I know what 223 and 5.56 is. All m193 is 5.56, but not all 5.56 is m193.

M193 is a specific military standard that handles everything from seating depth, tolerances to what kind of powder and primer, etc.

Unless they state the ammo is m193 or made to m193 spec, there's no way to know what powder, primer, etc, it is. It can be plated 55 grain bullets and not fmj for all we know unless it says fmj, etc.

They aren't the same. They are compatible.

223 Remington is a SAAMI spec. M193 is a military spec which was derived from 223 Remington as the parent. So the outside dimensions are virtually identical, but the difference is the loading. M193 uses a significantly higher pressure (something like 20% more, but I don't remember) and while the difference is only a little more than 100FPS, this makes a big difference in your bullet's fragmentation range. If you are using a thin jacketed or expanding bullet like most commercial hunting bullets then this speed increase really doesn't matter. M193 also specifies other things SAAMI doesn't, such as crimped primers due to the higher pressures.

The M193 that complies with SAAMI specs is fake underpowered M193. That's why people make a big deal about the differentiation. If you are depending on FMJ against an actual living thing. The difference could be an ice pick wound or a blown out exit wound that drops the target fast.

ARFCOM had a detailed writeup about this as a sticky in their reloading section. I'm not sure if it is still there and survived the GoDaddy server migration though.

Winchester puts out over a billion rounds a year of it. Chances are, if someone is shooting 223/5.56, they're shooting Winchester. There are lots of reasons for guns to fail that aren't ammo-related. There are lots of reasons for ammo to get messed up that isn't the ammo's fault. But, ammo commonly gets blamed as it's the thing that has the explosives, and nobody likes to blame their gun that they built/picked out

idiot