dmurphy317
but IMR has a powder, Trail Boss,targeted at the cowboy actionblack powder revolver/cartridge rifle market.
I have seen several ads for this powder in magazines... but I for some reason thought it was a nitro powder...
Trail Boss is designed specifically for low velocity lead bullet loads suitable for Cowboy Action shooting. It is primarily a pistol powder, but has some application in rifle. It is based on a whole new technology which allows very high loading density, good flow through powder measures, stability in severe temperature variation and most importantly, additional safety to the handloader.
Here is some additional information from Hodgdon on the powder...
http://www.imrpowder.com/data/rifle/trailboss-oct2005.php
All the information that I have found indicates it to be a regular "smokeless" powder. And if you look at this loading table volume for volume it would not be close... A suggested load for a 45-70 government with a 300 grain bullet is 14 grains (by weight) of Trail Boss,