Its pretty simple NO shoulder fired weapon on the planet will contain that much psi. HS-6 has a HUGE % of nitroglycerin and is usually used in very small amounts in 9mm and 40cal. Plus some shotshells.

It has NEVER been a recommended smokeless powder and never will be for a SML but if they would have used a recommended powder im sure it wouldnt have been so dramatic. Im sure the extreme effect was their intention otherwise they would have used a commonly used SML powder.

Ive seen a brand new Encore explode just as badly using subs. It appears to be an APP product.

http://www.youtube.com/watch?v=wtY1bT4Hh2g

How about a 500S&W because of a intentional over charge and a squib load.

At about 1:33 into the video
http://www.youtube.com/watch?v=sJv9VuXyjyQ

You cant fix stupid and if you are not upto the task of reloading CF ammo corectly, you are not upto using a approved SML either.