This treads a fine line between scratch and kit, I think. It's more or less a copy of a design by Gerald Wallace (Bohica) discussed here and here. Specifically his 13mm version, but mine has an 18mm motor mount; also I used one each 5055, 5060, 5070, and 5080 rings, which is what it says on his diagram, but in fact he used (for one version, at least) 5060, 5070, and 2 x 5080. It's not clear to me what Wallace used for launch lugs. I chose to put one 1/8" lug on a standoff near the center of gravity, high enough that the rod will clear the 5060 ring and go through 1/8" holes punched in the 5070 and 5080 rings. (Without a standoff, the two smaller rings would have needed gaps cut out of them, and I didn't like that idea.) Finish is Duplicolor Metal Specks red, rings are Rustoleum 2X gloss black, and there is a Testors trim tape line around the front end of the body tube.
I started off with Bohica’s Dead Ringer, on a B6-4. Have I flown this rocket before? Yes. On B6? Yes. How many times? Six. Was it stable every time? Yes. Was it stable today? Yes. Really? NO.
Did I check the shock cord before launch? Yes. Did it look healthy? No. Did I give it a tug and say, okay, it’ll work? Yes. Did it? Yes. Really? NO.
I recovered both body and nose cone, it’ll fly again. Maybe I’ll add a touch of nose weight. Weird, though, it’s always been stable on that motor before.