I have seen some experimental formulations of modified or hybridized composite propellants enhanced in the performance through the addition of powerful nitramines, namely RDX, HMX and lately the CL-20. But I doubt if they were used actually in big boosters for launching rockets to space.These recipes don’t exactly fit the strictly category of the composite or double based propellants but more of a LOVA gun propellants but with the metal fuel.
One basic formulation range I recently "re discovered" from my files.
AP, 80-100um( oxidizer)
18-22AP 10-15 um ( oxidizer)
18-22RDX/CL-20 1.7-3.0um( oxidizer)
8-10AN( oxidizer)
10-15Polymeric binder
6-65Aluminum fuel
20-24Plasticizer
4-16Cure catalyst 0.03-0.06
Burn Rate Catalyst 0.2-0.5
Bonding Agent 0.06-0.12
Stabilizer 0.3-0.4
Curative 0.9-1,9
Cross Linker 0.3-0.35
A basic nitramine containing LOVA gun propellant look like this.
HMX(2 microns particle size)
75 HTTP( block copolymer)
11.867Of Propylene oxide& Ethylene oxide Trimethylolpropane
3.167Lysine diisocyanate methyl ester
9.9675Titanyl acetyl acetonate 0.025
That's the problem with hearing information second-hand, I suppose. You never know for sure who is right.