I’ve been loading .44 magnum, .357 mag, and a little bit of 45-70 for a few years. I finally got my act together and assembled the necessary components to add .223 to the flock, mainly to feed my new-to-me M77. First 50 of many- 55 grain Hornady SP over 25 grains of IMR4320, Winchester primers, de-crimped nickel Federal brass. I have lots of uncrimped stuff, but the nickel plated stuff is once fired and looks so slick

Might be a camera angle but that round in your hand does not look kosher.
That a ring by the bottom of the neck? Looks kine a bulge,if so you are in for clambering problems.

It is a trick of the light. As a matter of fact, I chambered that very round (along with a few other random samples) to make sure it fed, loaded, and ejected cleanly.