The invention disclosed herein relates to solid propellant formulations, which exhibit good processing properties, good safety characteristics, desirable combustion properties, good safety. characteristics and excellent mechanical attributes. The solid propellant formulations disclosed. herein burn at a rate of about 0.5 in/s at 1000 psi and show no pressure slope break up to 8000 psi. The solid propellant formulations of the disclosed invention incorporate oxidizers of varying particle size to avoid a pressure slope break. The solid propellant formulations of the present invention avoid the use of large-size ammonium perchlorate (AP) particles having particle size in the range of 200-400 &mgr;m to avoid the pressure slope break problem, which typically occurs at about 2500 psi to 3500 psi. In addition, the formulations avoid using exotic burn rate catalysts such as superfine iron oxide, chromic oxide, catocene, or carboranes, because some of these catalysts are toxic and hazardous to the environment and give poor IM effects. Preferably, the formulations incorporate aluminum oxide having a surface area of about 85 to about 115 m2/g as the burn rate catalyst.