Ill take your earlier comment about me giving advice as a joke and answer you.
If you have your follower that is hollow and then have a bar with a angle on it that slides through the middle you could have holes at the right spacings on each end of the follower.
You would then load your pins then springs into the follower holes and hold them down with a shim, insert your follower into the cylinder and withdraw the shim, you then push the centre angled bit into the follower and this will push the pins and springs up in to the chamber, you then rotate the follower to trap them up and push through as normal with the pinned plug.
Look through the hpc catalogue to see it in the flesh as it were
I made one almost the exact same then found it in the hpc cat, i wasnt a happy bunny when i realised yet another idea was already being sold
