This design is a 3D model, that you can download for free from Thingiverse and print, of the Estes BNC-30D nose cone (part number 070244) that is designed to fit Estes BT-30 tubing. There are three models – the nose cone, the nose cone without the shoulder attached, and the end cap with a hole for the use of a screw eye or an eye bolt.

Estes models that were designed for this nose cone:
Kit # Kit Name
K-1 / 1201 Scout
K-15 Sprite
TK-4 / 0804 Hornet
0878 Scout III
1959 Scout II

You can download that model along with other models that fit Estes BT-5, BT-20, BT-50, BT-55, BT-60, BT-65, and BT-80 tubing.
https://www.thingiverse.com/thing:5191290