When reloading for a semi-auto proper case resizing is of utmost importance, that's one important issue. With a bolt gun it's easy to 'feel' when a round isn't chambering correctly. On a semi that round can easily get stuck as it's almost chambered. That can ruin your day if out & about.
I don't like absolutes with the crimp or no crimp debate. You do need good bullet tension to avoid any setback. Much/most of the time, normal bullet-to-case fit is enough, no special crimp. I have some 30cal 147 FMJ military bullets that are a bit loose in many cases. I've loaded some of these in 30-06 & 300WSM cases. I did give them a touch of crimp to hold them tight.
One can open a can of worms with talk about the Lee 'factory crimp die'. Yes, most any seating die can be adjusted to provide crimp. The Lee FCD does it as a separate step and is more forgiving with variations in case length. The Lee FCD is also infinitely adjustable, you can adjust it so you add little to almost no crimp. When I feel the need to crimp, I like to do it as an additional step. There are many tools for reloading one may find useful and the next guy will pass.
Read up on your prospective reloading project. Only load up a smaller amount until you test the loads. Always cross check your data from several sources.