Loading the Short Ten by Pete Lester

[Paul Harm]

Man, that's a shame, those cost a little bit. Those are made by Rockey Mountain and are turned from a solid piece of brass, so they're thicker than the Magtecks. They have a smaller internal volume, so that may contribute to you being able to use smokeless powders. Maybe the end was too small a diameter and allowed the shell to expand too much and crack. That would just be my guess. I found a thicker OS card gave me a hole in the pattern. Other guys had more luck. That was a 2005 Accurate reloaders guide. Here's a brief synopsis of the article:
The fundamental difference between a shotshell cartridge and a center fire rifle cartridge is that the efficiency of the shotshell is 100% dependent on the round itself. All the "resistive forces" must be generated within the confines of the round itself, no assistance is provided by the gun [the bullet meeting the rifling ]. The maximum peak pressure is reached long before the base of the shot/wad assembly has left the case. This means the efficiency re ignition and subsequent increase in pressure, is totally controlled by the integral configuration and assembly of the round itself. These constitute the main inertial mass [ shot mass ], the initial internal volume [ wad design ], the collapsing of the wad, plus the displacing of the internal assembly and the unfolding of the crimp. Crimping is certainly is one of the most importantly aspects of the shotshell reloading process. The influence of the crimp on ballistics is often ignored and assumed to be of lesser importance that primers and wad make/design. The fact is that the effect of the crimp-strength can totally overshadow the influence of other components and parameters. this is controlled by the following:

crimp depth

condition of the case

wad

wad tension

It is always wise to use a strong a crimp as possible.
Back to me - usually a roll crimp has lower pressures and I would think a card just glued in wouldn't have hardly any resistive forces so pressures would be even lower - too low. Black powder is a different animal so we can do things with it that doesn't work so well with nitro powders. The military has had all brass shells but they're roll crimped. I don't think they are worried about reloading them.

[Ron Scott]

Originally Posted by Paul Harm

Maybe the end was too small a diameter and allowed the shell to expand too much and crack.

Thank you for taking the time to retype all that info -- I appreciate it.

Regarding your theory about the end being too small. I don't think so because, 1) the black powder loads didn't crack the hull & 2) the overshot wad in both cases fit perfectly. But wow that I think about it, I used a different lot of brass hulls for the smokeless loads. Maybe they are harder than the first ones -- I could try annealing them. It would be worth testing because the load otherwise worked great. I'll keep you posted.