One thing I like about AT motors is I can leave the BP out of an RMS or remove it from a SU motor but still have delay smoke.Stuffing a -0 with wadding and taping it over tightly is another commonly recommended trick. I've not had consistent results with that either. Need to try that again too. Will probably ground test either technique before I try flights with it again, as I had two mishaps in three or four attempts before.
I am not sure about the new AT SU motors with the plastic ejection charge wells but I assume I can still remove the BP but keep the smoke ?
-- kjh