I have a bunch of rockets with the teabag-style attachment for a rubber shock cord. I've had a couple fail but generally this technique has been reliable for me. In some applications, though, I've wanted to change out the teabag-style recovery system. I do this when: - Narrow bt or want more space in bt for chute - Heavy residue in bt from ejection charges makes new teabag gluing suspect This works best with cardboard CRs, I have not tried it with a sleeve style CR. 1. I bought a 1/8" standard Drill bit from Irwin that is 12" long. It is not a concrete-style bit, those wouldn't work as well. $5. 2. Pick the spot you want to drill a hole in the aft CR, I aim for halfway between the MMT and BT but not interfering with motor hook. 3. Hand-spin the bit to cut a hole in CR. 4. Carefully slide bit further through aft CR until contacting the foreward CR. 5. Ensure the bit is plumb with the rocket - you want the holes in line with each other and the BT. 6. Spin the bit again to cut a hole in the forward CR. 7. Ream the hole with the bit, clear fibers and remove. 8. Put some CA glue on your kevlar thread and roll out straight. The goal is to stiffen the kevlar thread into a needle. I found 6" to be enough. 9. Once thread is dry and straight, thread through the two holes. Patience is key. 10. continue to feed kevlar through the rocket, trim the CA'ed section of kevlar off, tie a loop to accept some elastic. 11. Pull kevlar from the aft end of the rocket until the kevlar line is below the top of the BT. This eliminates the kevlar causing a zipper on ejection. 12. Cut kevlar to appropriate length at aft end of rocket. Tie a loop over a spare motor tube, remove spare motor tube, and slide the looped kevlar over the motor tube on your rocket. 13. Put a dab of glue ove rthe aft 1/8"hole with the kevlar running through it to control ejection gases. So that's it. I found this retrofit to be helpful, hope someone can benefit from this.