Anyone else use a crash box sometime?

Yes back in the day I ran (I hate to say it but I ran a Minice M22) I would grind every tooth off the brass blocker ring and every third tooth off the syncro this would allow clutchless up shifts but to down shift you did need you to double clutch or it would not go in very well. After half a season you would have to pull the trans and go through it most of the remaining teeth would be sharp as a razor and they snap off then and the trans was toast.