I have been seating my .223 rounds with my 22-250 bullet seating die. It seems to work fine(better than the .223 die)...should I be doing this?

The 22-250 neck shoulder junction is about .110" (deeper) longer than the 223. So the larger 22-250 die could allow the case to be off center as the bullet started into the neck as it would be unsupported at the start. You could get some major runout, which hampers accuracy. Do you have a runout gauge so you could load a few with each die and see if there is a differance?

I can also see the bullet tiping sidways a little too much and hit the shoulder area of the die and kink the neck. The 22-250 body area is a bit bigger than the 223 and it would happen quicker than in a 223 seating die.

Ok. I will pay attention for those things. It seems to be working great so far. I will see how accurate they are. The Hornady seating die I have is just no good for me.

What seems to be the trouble?

I keep flattening my brass with it LOL. Their is nothing wrong with the die, im just used to Lee dies.

IC,..... well the only thing I can think of is that some dies have a crimp feature. You may need to back the die off the shell holder a little. Otherwise I'm not quite sure what you mean by flattening the brass.