Re: SMc Cartridge Developement.
Now I'm on the spot! Well, I'm no engineer, and not bashful....
The essence of what they are doing is the use of a hemispherical shoulder on a short wide case, which apparently gives them a velocity boost for a given charge(efficient) due to a myriad of engineering priciples I cannot accurately represent here, though they are in the two articles published to date.
One of the guys is a retired engineer from Morton Thiokol. Their thrust seems to be that of ignition efficiency, as relates to primer shock waves, shoulder design, and burn thru the shear zones of dynamic powder charge. Whew!
Tyey're working with Norma for pressure validation and brass, and the data published to date indcates a gain similar to moly coat except the magnitude is greater. Same charge=greater velocity & less pressure w/ their design. Or option 'B' Equal the pressure and go like hell... Their data suggests that there lies a threshold on the low end below which little gain is found, and possibly on the top end as well except the pressure will still remain less per equal load. It is a helluva load to digest.
The powders they've been working with are very slow [img]images/icons/cool.gif[/img] and some of the calibers relatively small(6mm), but as I recall up to .308 or maybe bigger. Sidebar: Their analysis of case shape found the 45 degree shoulder the most efficient other than their own design. Their additional consideration being VERY fat case design due to the above mentioned shear issue. I don't know if this will become useful application or just theoetical research. Interesting nonetheless, particularly in regards the subject of this site.