How to increase burning speed of nitrocellulose?

Material: 98% sulfuric acid, nitric acid concentration requirements 95%, cotton. preparation: volume take 25ML nitric acid into 100ML beaker again injected 45ML sulfuric acid, mixed uniform. reaction liquid placed ice water bath cooling to 10 ° C.2 grams around cotton tear. voted into mixed acid. makes its completely mixed acid invasion didn’t. invasion bubble 20min (reaction temperature super 30 ° c) off waste acid. with water washing rough NC at least 3, drying, that products containing nitrogen volume up to 14% burst speed >5000m/s