There are a number of techniques to ”improve” cylinder shell burst powder, or at least substitute for commercial black powder at lower cost with equal effect. Perchlorate polverone (made by substituting potassium perchlorate for saltpetre, weight-for-weight, in your usual polverone formula) can be used. A friend of mine had good success using a mixture of 1/3 perchlorate polverone, 1/3 regular polverone, and 1/3 commercial 2FA. He used it in the normal size canulle for a given size of shell and spiked and pasted the shells as usual. He got excellent break patterns, at least as good as with all commercial powder. “Burst strengtheners” typically consisting of a granulated slow flash powder can be added to polverone and the mixed granules used in lieu of 2FA. A typical “forte nitro” might be: Barium nitrate 10 Dark aluminum 5 Sulphur 2-1/2 Dextrine 1 Damp with water granulate through window screen and allow to dry. Mix 2 or 3 parts polverone with 1 part of these granules use the mixture in place of black powder as burst. Slow flash powders like the above, using barium nitrate or saltpetre as oxidizers, can also be used in flash bags. They are less harsh than regular salute flash and are drossy enough that (properly proportioned) such flash bags can be used with color stars and won”t blow them blind.