This is my primer seating tool of choice
when I'm reloading with a single stage press. It is a huge improvement over the standard swing type priming arm that comes
with most presses. This little gizmo has been around for a long time (I've had mine for over 30 years). It's hard
to beat because it installs the primer on the down stroke of the press handle, and it allows you to really "feel" the primers seat.
When you're seating a primer, the angle of the press handle is almost level so that you have a jillion times more press
leverage. Not that you need the extra power, but this is what lets you feel the primer as it's being seated. I've never seen any
auto priming mechanism (those that come with reloading presses) that could provide consistent primer seating feel that even
comes close to the way that this unit performs. This is a great tool, and it costs less than $30. I wouldn't
want to be without it.