There are a few other subtle differences too. If you use the priming device on a RCBS, you may have to ream the inside hole of the shell holder so the primer punch will fit. Also, the head thickness varies from brand to brand. This won't be a problem with pistol cases but with rifle cases, a thick shell holder won't let the case go into the die far enough to set the shoulder back properly. I have an assortment of shell holders and dies. I ground the tops of all my shell holders so I have a little adjustment without the die hitting the shell holder. Other than that, they're pretty much interchangable.
