My first suggestion is go to the Z-Hat home page and look at the .375 Hawk data and I think the Scoville/Rifle Hawk article is there. Also the 3 & 4 Barnes manuals. Z-Hat has a CD with a bunch of load data and most of it is pressure tested from the fellow that started North Fork Precision. My loads are IMR 4895 and RL-15. IMR 4320 will work also.
On top of this I have it in a Rem. 760 pump. My max. loaded length is 3.25" because of the ejection port size. A bolt gun will let you load longer.
The .411 Hawk duplicates, on a '06 hull, the 400/450 rimmed British cart. Want to hunt elk in the pole patches and buffalo with the same gun?
