Yes I am saying the cap is hard to get on so that you are sure it makes good contact with the plug. There must be no gap in there or you will get RFI. The plug caps are new - I just got them back from C&H. The plugs are new.
Other people have used this type of cap for years. Its the same type of cap as used on most mag engines except the shield is supplied with a pigtail to ground the ignition. A magneto is already grounded.
I just wonder if someone has found some kind of substance that would help this from creating RFI. Maybe a conductive grease like is used on heat sinks would be better?