Re: 300 RUM Ack Imp
The Tomahawk is the 300 Remington Ultra Mag improved, from Dave Manson reamers. 35 degree shoulder. Ray Romain out of Brockport PA has built several of them, and I believe was a big part in designing the reamer. He built mine.
It shoots best with ball powders like H 870 (which might not be available anymore), and 220 to 240 SMK's. The ball powders are best when used in cool weather 50* and colder. Hotter weather can cause problems with ball powders. Retumbo is also a good powder for it. You can start with 300 RUM loads and slowly work up. It works best with barrels 32" and longer!
Hope this helps,
"A tie is as good as a loss, and no one remembers second place."