64Springer
75 Cal.
The problem I see with the 209 set ups is that they are too high.I do have a few 209's that I've been sitting on for a few years. If I can find a nipple system for my New Englander that would be a good option. I already have one for the Hawken in the house, but I don't shoot that one. Its belongs to my wife and she said I can't play with it.
Sometimes it puts the nipple/hammer angle out of alignment.
And the taller the 209 system is, the less the hammer gets to travel. Less travel means the hammer is no longer picking up speed. Less speed means less force applied to the primer.