The BATFE will argue this point with you. For reference, look at air bags.
From ATF Explosives Newsletter June 1997:
"In order to obtain the explosive material used in the airbag initiators and produce the initiator for installation into an airbag unit, a license as a manufacturer of low explosives is needed. If manufactured initiators are purchased from an out-of-state source for installation into an airbag device, a Federal user of low explosives permit is required. Once the explosive material has been incorporated into the airbag device, it may be exempted from regulation."