I got the 2016 brass inserts and they are too tight for the 2018's.I did adapt them though with not much trouble.I first screwed a field point into the brass adaptor and chucked the field point in a small drill press.You could also use a drill.I turned on the drill press and used a small mill file to reduce the diameter of the insert.You need to go easy and check it often.I kept a short section of shaft handy to test for fit,one left over when I cut my shafts to length.Stop the drill press check the fit,hit with the file where needed.
It took a few minutes per insert and I can't remember the exact finished weight but app.95 grs and they were all only tenths of grs apart in weight.It was well worth doing.I like the brass inserts.