For those that want to know.
http://www.reloadingroom.com/page31.html
Originally developed in 1972 by Wyoming pistolero Steve Herrett and Bob Milek, the .30 Herrett was designed specifically to be a highly effective big game cartridge in the 10" barrel of a Thompson Center Contender pistol. After 20+ years, the Contender is still the only firearm chambered for the .30 Herrett (available as a regular chambering or from Fox Ridge Outfitters, the T/C Custom outlet), but the combination is still a good one. Small enough to have excellent loading density yet large enough to give good velocity, the .30 Herrett is to the .30-30 what the .308 is to the .30-06. In other words, nearly indistinguishable results from a smaller, more efficient package. For the past few years I've used it for most of my deer hunting, and I consider it to be just about ideal for most pistol hunting applications.
If you doubt that, compare the .30 Herrett and the .30-30 calibers in the Contender. The Hornady Handbook, Fourth Edition lists both in their section of reloading data for the Contender. With the same 110, 130 and 150-grain bullets, the Herrett delivers up to 400 fps more than the .30-30 when both are shot in 10" barrels. Lighter bullets show the most added velocity. In a 14" barrel, the larger .30-30 case regains a small velocity advantage, especially with heavier bullets, but the difference is negligible. From a 20" carbine, the .30-30 launches a 110-grain bullet at 2,600 fps, only 200 fps more than .30 Herrett wrings from a tube only half that length. From my 14" T/C barrel, the stubby Herrett round gets 2575 fps, virtually identical to .30-30 carbine performance. The increased loading density of the smaller round when using faster powders gives the Herrett an efficiency edge. Plus, the Contender can use sleek, pointed bullets with high ballistic coefficients, a distinct advantage over most .30-30 rifles.