Marshall,
You are right on the money when you said that the .30-30 is based on the .38-50, the father of the .32-40 & .38-55. The .38-50 is 2.00" long and when Winchester engineers reduced the neck diameter to hold a 160 grain .30 caliber "metal patched" bullet in 1894, the cartridge case grew to 2.03" in length. Thus the .30 Winchester Smokeless was born. A.K.A. the .30 Winchester, .30 W.C.F., .30-30 W.C.F., .30-30, & .30-6-100.
The last reference was illustrated in the Dec. 1896 Winchester catalog. It was a "Short Range" cartridge for "small game where the more powerful cartridge is not necessary". It featured a 100 gr. lead bullet over 6 grs. of smokeless powder.
As you can tell, I'm a .30-30 nut!
Pourboy,
The .30-30 and N.R.A. Cowboy shooting go together like ducks and water. I personally like 200 grain bullets on the rams for a little more insurance. I can get slightly over 2,000 f.p.s. using slow burning H414, W760 or Hodgdon's 4350 Extreme.
For 170-180 grain bullets, 36-37 grs. of any of these powders is tough to beat in the .30-30. Accuracy wise, I have found nothing better in 22 years of .30-30 cast bullet shooting!
Good luck on those silhouettes!