I always insert the core seated jacket in the die and then follow it with the punch. I’s kinda of a fine line between bullet in, up comes press as finger moves out of the way.
Of course, if things do not go as they should, your finger gets intruduced to the concentrated pressure generated by tip of that punch.
I do it this way because with the 30 point up, I can use my body to apply the pressure on the handle rather than just my arm and shoulder.
Which brings up a point that no body has talked about in this thread.
Several years ago, a very well known bullet maker and Hall of Fame Shooters gave details on seating cores to where the core seated jacket is undersized from the finis diameter of the bullet. The idea was, there is always a small amount of spring back with the jacket, which is a copper alloy. However, the lead core has zero spring back. If the seated core is the same size as the finished bullet, it could produce a loose core.
Or something like that.
I tried it. I put just enough core pressure on the seated jacket so the core seated jacket was a tenth under the final bullet size.
They were the worst shooting bullet I ever made. So I continued seating the cores where they have a certain “feel” coming out of the core seating punch, (and of course the correct length), and they are the same size as the finished shank on the bullet, which is .3081.
When I insert it into the point up die, it sticks enough so I can get my finger out of the way.