Just push them flush and not with the skirt into the rifling at all. With a pcp things are different, but a springer relies on the pressure build before it overcomes the force to push the pellet into the rifling. In my own FAC TX200 i used the ball end of the pell seat to just 'click' the skirt into the rifling. Net result was a loss of 80 fps, in .177, and this has been seen by 2 other local shooters as well. I saw one using the pell seat and I asked him to fire his gun over the chronograph, with and without seating. His gun lost almost exactly the same 80 fps. Both of these guns were shooting 900 fps and dropped to 820. This was very early in my springer history, but I have also seen some low power springers, 500 to 600 fps range, that actually benefited, powerwise, from the seating.