Maybe contact Apogee customer service?
is this a standard BT-20 (I am guessing yes)
also take a look at the specs for the nose cone on the Apogee site, did they SAY the outer diameter was not a match? If not, I’d say they owe you some replacements. At least if you let them know they can update it on their site so no one else has to go down same rabbit hole.
I just looked at the web site, and the yellow nose cone outside diameter is listed as 0.736”
Plastic Nose Cone for 18mm Model Rocket body tubes
which IS also the listed outside diameter of the BT-20.
Made from high-quality kraft paper, with a white overwrap. You can write on the tube with a pencil, or color them with markers. Very tight spiral seams, so it is easy to get a smooth surface finish. Compatible with Estes BT-20 tubes and nose cones.
curious if this is a manufacturer QC Problem or the manufacturer mold maker just messed up. In any case, would be curious to see what Apogee says when you contact them.
straight trails (unless you build like me, then I wish you a straight trajectory with cool corkscrew trails!)