Originally Posted by Royatl

The Mini-Brutes were first on sale at NARAM-13 in August 1971, but they had been shown over the spring at the various model rocket conventions as MPC introduced their Minirocs and Minijets.

The "Shorty" motors were phased out over the next year.

Also, I think you mean Sprite (the tumble recovery, ring-tailed rocket) not Sprint (the low drag form factor rocket which used standard motors.