I've been trying to improve the reliability of my 1lb core burners and also get as much kick out of them as possible. Currently I work with a formula which is as follows:
C (Willow AF): 31%
The KNO3 is ground to a fine powder and I simply screen everything together. When I ram this into my purchased spiral wound tubes they work pretty well but not quite as powerful as I think they could be. I know many people use 60:30:10 so I know my mixture could be hotter.
I've had some CATO's in the past using the hotter ratios so I went back to my tried and tested 55:31:14. Now tTo reduce dust and to see if I get a performance boost I wet the green mix like I do when I granulate BP. I then used a fine grater to create the granules, let it dry and rammed another engine. I don't add any dextrin and the granules are fairly weak which is no problem, I only need to keep them for a few hours anyway.
This motor CATO's even though I was very careful to ram it just as well. The plug and nozzle held, it simply split the tube open and made a fairly decent bang! I was also careful not to light the core all the way up, I specifically only ignited maybe the first 30% using blackmatch after a visco fuse. This was exactly how I fused the successful motor.
I've read a few places that the wetting process does increase the strength of the mixture but this seems excessive. Any other thoughts on what it could be? Does anyone here recommend convoluted paper tubes and know where to get them? I presume I could work with hotter mixes if I got stronger tubes.