The older plastic nose cone had a small nib at the shoulder. This prevented the nose cone from seating all the way into the tube.
The second picture shows the fit after shaving off the nib.
I never liked this small round shock cord attachment. It always seemed weak.
It was cut off and a hole was drilled by spinning a #11 blade in the shoulder plastic.
TIP: Save an old blade or two for jobs like this. You wouldn't want to ruin a new sharp blade by spinning it into plastic.
The nose cone weights were a little surprising.
The plastic cone weighed in at .43 oz.
The balsa cone and screw eye together weighed .37 oz!