Not hard, just different. Look at a good 'how to' book. There are some things you have to watch out for. Lubing cases is essential.

Often bullet seating is done by chamfering the mouth, depending on the bullet. Crimping is different, sometimes there is no crimping.

Like mentioned before, case length is important.
It can complicate headspace, which needs to be understood in bottle neck, rimless cartridges because it's different either than rimmed or cartridges like the 9mm that headspace on the mouth of the case.

Also, rifle cartridges can fail in ways that you don't see in straight wall pistol cartridges.

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